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KIC 8462852: Where Are We After Eight Months?

The unusual star designated KIC 8462852, and now widely known as ‘Tabby’s Star,’ continues to be an enigma. As discussed in numerous articles in these pages, KIC 8462852 shows anomalous lightcurves that remain a mystery. Recently Michael Hippke explored a related question: Was the star dimming over time, as postulated by Louisiana State’s Bradley Schaefer? The two sharply disagreed (references below), leading Hippke and co-author Daniel Angerhausen to re-examine their conclusions. Now, with further collaboration from Keivan Stassun and Michael Lund (both at Vanderbilt University) and LeHigh University’s Joshua Pepper, Hippke and Angerhausen have a new paper out, peer-reviewed and accepted for publication by The Astrophysical Journal. What follows are Michael Hippke’s thoughts over the controversy as it stands today, with the dimming of KIC 8462852 again in doubt.

by Michael Hippke

hippke-photo

Tabetha Boyajian et al. released a paper on the preprint platform astro-ph in September 2015, which quickly got the Internet up to speed. Planet Hunters, an open community that searches data from the Kepler space telescope, found this unusual star that is now known as “Tabby’s Star”. It is observed to undergo irregularly shaped, aperiodic dips in flux of up to ~20%, much more than expected for any orbiting planets.

Media interest skyrocketed in October, when Jason Wright et al. released a preprint in which they discussed — among many other possibilities — the idea that the dips could originate from an alien race building a mega-size construction around the star, perhaps in the form of a “Dyson sphere”. Could it really be true that we found the first ever evidence of a powerful extraterrestrial civilization? A controversial discussion quickly ensued.

Further examination in other electromagnetic wavelengths only brought disappointing null results. The star was unremarkable in the infrared, showed no sign of artificial laser pulses, or radio emissions. The only somehow realistic astrophysical explanation was offered by Bodman & Quillan, who suggest the presence of a large family of comets, and which as of today are considered to be the “best” explanation.

comets-converging-on-star

Image: Cascading comets around a distant star (NASA/JPL/Caltech).

In January 2016, Bradley Schaefer released a preprint that examined historical photographic glass plates from the Harvard Observatory taken since 1889. His results seemed to show that “Tabby’s Star” had dimmed by 20% since that time, which was interpreted by many in the media as an indication of a quickly proceeding alien construction.

This was about the time when Daniel Angerhausen (an experienced astrophysicist at the NASA Goddard Space Flight Center) and I got interested. Our basic thought was: “If this were true, it would be the greatest thing in history!” We wanted to see the evidence with our own eyes, because honestly, we had big hopes ourselves. Initially. We think it is very human to be wanting to be part of something big, or at least seeing it happen. So, we had hopes that something big had been found, and we had the chance to see it happen.

So we dug into the Kepler data and found them rock-solid. These strange dips were really there! Also, we downloaded the historic Harvard data and plotted them. Schaefer had binned them in 5-year intervals, but behind these bins, there were actually over a thousand individual data points. When we plotted these on our screen, and overlaid a linear trend, we became very disappointed. The Harvard plates have an uncertainty (over 100 years) of order 0.1 to 0.2mag, and this was also visually evident. We had serious doubts that this dimming trend was valid.

We selected some comparison stars, which had similar scatter and trends, and decided that we would release our findings as a preprint on astro-ph. KIC 8462852 is a very special case not only scientifically but also in the way it was discussed in the community. It became one of the most publicly discussed astronomical objects. Many articles on this fascinating object (including its original detection) were published on astro-ph before peer review and some even called it a revolution in scientific discussion, making it real time and on various social media channels involving the public.

Bradley Schaefer himself gave at least 2 interviews on the day his (at that time not peer-reviewed) manuscript came out. Following his own arguments that “putting up unchecked and false claims is bad all the way around”, we had no other choice than putting our doubts on his results out immediately, so that the community, the involved media and the interested public did not have to wait many months for the formal rebuttal. We also decided to do this to keep the discussion public and have interested laymen follow it; we even gave a recipe to reproduce the data using the publicly available Harvard DASCH [Digital Access to a Sky Century @ Harvard] data for the interested reader [see KIC 8462852: No Dimming After All?].

The immediate reactions to our preprint were overwhelmingly negative, just as most of the other publications on KIC 8462852 have been. In retrospect, we attribute this to two very human factors. The first was that some of our previous assumptions and methods were indeed inconsistent and the choice of some comparison stars questionable. But errors are human, and everybody makes them at times! While we believe that these errors did reduce the clarity of our result, we still believed that the result itself was correct. This view was not shared by Bradley Schaefer, who published his reply on Centauri Dreams [see Bradley Schaefer: A Response to Michael Hippke]. The other issue we see was that most readers wanted to believe that this thing was real. Schaefer was an authority, while Hippke was described as a “novice”, and “proof by authority” seemed to weigh in.

As this time, we decided to do two things. First of all, we cut all media connections. Second, we started collecting all issues and questions raised by Schaefer, and many others in the community and here on Centauri Dreams. “Tabby’s Star” started off as a community project, and it continued to be one! The pure number of emails we received was enormous. Our favourite mail, which was received via hand-written paper mail actually, was by an American who said that he was once captured by these aliens himself and is a first-hand witness!

Most feedback was incredibly helpful, however. We gained several co-authors who contributed several more analyses, statistical tools and better ways to select comparison stars. We also got an invitation to the ASTROPLATE conference in Prague, where Michael Hippke met most of the glass photography community. We spent a whole week discussing calibration techniques, scanners, and fungus (one of the reasons why digitization of these plates is so important!). These fungi are actually called “gold disease” owing to their look on the glass. We enjoyed long evening talks about the millions of plates that still await their scientific use, and after all of this, had the chance to discuss our own findings in a presentation and discussion.

During all this, and afterwards, we continued the peer-review process at the Astrophysical Journal. We have published several papers in this journal before, and, as always, it was a very professional process. Yet, they appointed two referees instead of the usual one, and we went through several rounds of question-and-answer to nail down every detail. This took considerable time. Now the paper has been accepted for publication (and is updated on astro-ph). From the feedback we got, and given the much more detailed than usual review process, the study is probably one of the most solid and waterproof papers we ever published. We believe that it is established beyond any reasonable doubt that no dimming can be found within the uncertainties of 0.2mag per century.

Now, what does that mean for the mystery? Are there no aliens after all? Probably not! Still, the day-long dips found by Kepler are real. Something seems to be transiting in front of this star. And we still have no idea what it is!

The cool message here, however, is that we now for the first time in human history have technology that can at least in theory detect such things, with upcoming missions such as JWST and PLATO. To solve the mystery, there are now several more projects under way. The American Association of Variable Star Observers (AAVSO) has collected thousands of amateur astronomer observations to discover new dips. Others, such as the Las Cumbres Observatory Global Telescope (LCOGT) have joined the effort. Observing further dips in different colors can reveal information about the chemistry of the transiting object, which might confirm or reject a cometary origin. Who knows, perhaps these telescopes have already captured some exciting new data, and any day researchers might publish a paper that solves the mystery!

The paper is Hippke et al., “A statistical analysis of the accuracy of the digitized magnitudes of photometric plates on the time scale of decades with an application to the century-long light curve of KIC 8462852,” accepted at the Astrophysical Journal (preprint). A Vanderbilt news release is also available.

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Comments on this entry are closed.

  • Tim Van Putten May 10, 2016, 9:14

    This is not as confusing in the Electric star model. The variability in light output is possibly linked to the electrical flow through the star.

    • Thomas Tarrants May 10, 2016, 15:37

      So why this star in particular and not the others?
      Why not stick to real physics? Magic/EU may always be a sufficient explanation, but never a necessary one.

    • Moebius May 11, 2016, 3:11

      The Electric star model is not science, it’s wrong from any angle you approach it and can be disproved by elementary physics.

      A good read for those who are still not convinced that “electric star” pseudo-scientists have no idea what they’re talking about:
      http://www.tim-thompson.com/electric-sun.html

  • EricSECT May 10, 2016, 9:17

    So….. probably NOT a century long fade for Tabby’s Star. OK, good data point.

    Still…. How best to explain the ginormous dimming events, 750 days apart and with no IR excess? I do not favor the comet swarm hypothesis, it seems contrived. I instead lean towards Dirk Bontes’ idea in a previous CD post:

    https://www.smashwords.com/books/view/632855.

    To summarize: “….In Cepheids the light is temporarily blocked inside the star itself by a layer of completely ionized helium, preventing some light from escaping from the star.
    My solution is that in KIC 8462852 something similar is at work, though the star itself is not a Cepheid.
    Cepheids and various other types of star are in the instability strip of the Herzsprung-Russell diagram and KIC 8462852 is in a position on the Main Sequence of this diagram that is very close to this instability strip.”

    My take is that his proposal makes sense, I can’t shoot any holes in it. Any one else? Supporting evidence of this proposal would be to find similar stars doing the same thing.

    • LaszloM May 13, 2016, 17:58

      The process you describe is very well known. However, stellar pulsation doesn’t work (and it actually cannot work) the way the dimmings happen in this star. The description is oversimplified, what happens is that in the partial ionization zone of helium or hydrogen acts as a valve mechanism. Atoms (or less ionized ions) have a larger cross section and thus higher opacity and trap more light temporarily, creating excess heating and outward expansion. When the temperature is high enough to ionize the particles, the opacity drops, more light can get out, and the star can contract. BUT, this happens continuously and in a clockwork fashion. What’s more, the period of expansion-contraction (and thus dimming and brightening) very strongly depends on the stellar sctructure, and A-F stars pulsate in a matter of days and hours, much faster than the dimmings in Tabby’s star. Here is what a pulsating light curve looks like:
      http://inspirehep.net/record/882499/files/fig1.png

      • EricSECT May 16, 2016, 10:35

        LaszloM wrote:
        “…this happens continuously and in a clockwork fashion. What’s more, the period of expansion-contraction (and thus dimming and brightening) very strongly depends on the stellar sctructure, and A-F stars pulsate in a matter of days and hours, much faster than the dimmings in Tabby’s star.”

        Agree: This is a true statement for all our other known variable stars. I am no astronomer and have only a basic grasp of the physics. And agree: There is no regular and periodic flux change for Tabby’s. But…. Perhaps Tabby’s is just on the cusp of instability, just at the point in life where it is about to transition from a stable, non-variable star into a variable (perhaps this evolution takes on the order of 10,000 years?). More than likely, flux does not immediately go into a regular and periodic change of flux. Probably sputters and fizzes for thousands of years, chaotic. Have we watched any other star make this transition to compare?

        I would like to hear Dirk Bontes speak up and defend his proposal.

        • A little fish May 16, 2016, 16:38

          A magnetic reversal is a chaotic transition, during this event the magnetic field is more or less intense on some area, the magnetic poles moves, the magnetic field lines are very intermixed…
          But, i dont know how the magnetic reversal of a star work, i have wrong ?

          If i’m right, with all this chaos, some area of the atmosphere should be more or less ionized than others, resulting in a inhomogeneous and inequal opacity of the star atmoshpere.

          And, if the opacity is inhomogeneous, with the 0.88 day rotation of the star, we expect to see something on the ligth curve when some opacity different area come on front of the star.

          No ? I’m wrong ? I miss something ?

        • LaszloM May 17, 2016, 9:58

          I don’t think stars would do that, even at the edges of the instability strip. (A lot of delta Scutis don’t reach even 20% in their pulsation amplitudes.) The amplitudes diminish towards the edges: at the blue edge the partial ionization zone gets close to the surface, so there is no more envelope to move. At the red edge, the driving layer gets deep enough into the convective layer that convective motions inhibit global pulsations. So even if the pulsation would stutter, the overall amplitudes were small. Anyway, none of the (pulsating and non-pulsating) A-F stars with similar physical parameters observed with Kepler show similar dips, so this feature would be still unique. We have a relatively good handle on the theory behind stellar pulsation: the only difference is that Tabby’s star would throw a wrench into stellar astrophysics instead of the physics of circumstellar material…

  • Planetsam May 10, 2016, 9:33

    As one of the Planet Hunters members who found this object and co-author on the paper, I’m glad so many in the scientific community have taken an interest and I enjoy reading the research being done. It’s great when you find something that no one was expecting, which was the whole point of Planet Hunters.

    That said I feel a little disappointed with the media focus on aliens and how it has brought out the rather crazier enthusiasts. Don’t take it to heart Michael, there are people who want to believe and they will attack anything that contradicts that, but that isn’t how science works.

    • Abe Hoekstra September 12, 2016, 9:30

      Hi Sam, how are you doing? You are not only one of the members who found the eclipses in the lightcurve of KID 8462852, you are the first one as well, and I think you deserve a lot more credit for that, as the Planet Hunters community has chosen to largely ignore those i.e. you and me – who were there from the beginning, which is not right imho. Without you Planet Hunters wouldn’t have a scientific paper, and I am still disappointed by the lack of gratitude they have shown you and me, whereas others now reap the rewards of our hard work.

  • Alex Tolley May 10, 2016, 9:46

    Good to see that Science as a process is working. Schaefer was making the extraordinary claim that needed extraordinary proof. This claim now seems to be falsified.
    I’d be interested to hear whether Schaefer accepts the new analysis.

    Something seems to be transiting in front of this star. And we still have no idea what it is!

    That seems a little strong. We do have an idea, several in fact, although the comet hypothesis seems the best fit to the known data so far. New observations should be able to further constrain teh possibilities and shed light on the phenomenon.

    • Paul Carr May 10, 2016, 12:42

      I consider the controversy still alive. We need some sanity checks and more data. I understand there are some Russian plates that have been measured – just a few, but possibly quite interesting. It would seem to my untrained eye that the available contemporary measurements are above Schaefer’s trend line, but of course he made no claim that the dimming would continue. Even if real, it could just be a very long period variability that is not well understood.

      • Michael Hippke May 10, 2016, 15:17

        Yes, I encourage everybody to double check all data (publicly available) and results. During the last weeks, new data came available which I couldn’t add to the paper as the refereeing was already in progress.

        There is photometry from APPLAUSE (https://www.plate-archive.org/applause/) which has 103 datapoints from the German Observatory Bamberg. I met Harry and Tuuvi in Prague, and we examined the data together. There are some calibration issues, but these data are also flat within 0.2mag between 1915 and 1981.

        I also met Helena Roshchina in Prague, and she kindly offered to digitize the Pulkova plates. There are 10 plates which are also flat within 0.2 mag between 1922 and 2001. These data are available here: http://za-neptunie.livejournal.com/229749.html

        For Sonneberg – it’s all on DVDs and will take some time to copy & extract. Honestly, I’m not sure if that’s even worth the effort any more?

  • Harry R Ray May 10, 2016, 10:20

    The drift that I am getting here is that ALL photographic plates(i.e., not JUST the DASCHE plates, but the Sonneberg plates as well) are unreliable except for MAJOR dimmings(0.5 magnitudes or greater. Hippke et al, correct me if I am wrong. The big issue I had with the DASCH plates was the break period with no data, leaving the leaving the INTERPRETATION of the early and late data pretty much in the eye of the beholder. The Sonneberg plates have only about a half-century of data, but with NO BREAK, so that the interpretation data is null and void. If the Sonneberg plates are ALSO unreliable, then the comet interpretation is back in play, with the possible EXCEPTION of the “Q8” lightcurve(as most readers know, Einiac and I have a lively debate going on this one). Perhaps Hippke et al can now turn their attention to this particular part of the kepler data and come up withs a NATURAL explanation for this increadibly SMOOTH lightcurve with an “ingress” that is twice as long as its “egress”> I put quotation marks around those words because they don’t even apply if the natural cause is INTERNAL(like the ionization of Helium, which was recently put forward by a reader, and which I now tenf to FAVOR unless someone in the professional scientific community can REFUTE it).

  • David Grinspoon May 10, 2016, 10:35

    I’ll look forward to reading this paper. But I don’t think that the lack of radio signals or laser pulses are “disappointing” or have much bearing on the question of whether or not the unusual dimmings are due to an artificial construction. It was certainly worth looking for these, but it was best regarded a long shot, not as a way to test the artificial nature of the obscuring objects, and the thought that such signals should be *expected* from a system with technological activity is rather silly and laden with questionable assumptions. Likewise, the question of long term secular dimming is important but not really a crucial determinant of the “megastructures” hypothesis.

    • Jim Strom May 10, 2016, 12:55

      Disappointing, perhaps in the sense that the stakes were potentially so high, but not disappointing in view of the realistic expectation, since any “leakage” or blackbody radiation from a structure would probably be isotropic and too weak to be detectable.

      • Eniac May 10, 2016, 22:51

        Some fields of research are intrinsically disappointing, yet the research is still useful in pushing back the boundaries of what we know and see vs. what we precisely know, but can’t see. Expanding that boundary is useful, and there is also that very slight, exciting chance that we might be proven wrong. Disproving Einstein’s theory of relativity is one such frustrating endeavor. Finding alien life is another.

        • Michael May 12, 2016, 3:10

          ‘Disproving Einstein’s theory of relativity is one such frustrating endeavor.’

          This will be difficult because it is based on Maxwell’s theorems, if relativity falls so does maxwell’s, no sign of that yet. They may be a discontinuity in the theorem at extreme gravities which we have not calculated yet and where all the troubles are.

  • Gary Northfield May 10, 2016, 11:18

    I’m seeing lots of headlines surrounding this paper screaming that the idea of aliens is dead and buried thanks to these findings. But, all I’m reading is a counter-argument to the 100 year fading. In fact the big dips are still completely unexplained! Talk about muddying the waters.

    • Eniac May 10, 2016, 22:58

      The muddying was all done by Schaefer, who brought up the perceived dimming and somehow concluded from it that the very real dips cannot have been caused by comets. Without reasoning about the dips or comets themselves, at all. Incredible that so many fell for it.

      • Nam Nguyen August 26, 2016, 15:58

        What about the gradual 4 year dimming observed by Kepler? Is that still real?

    • Michael T May 11, 2016, 4:39

      I absolutely agree. I understand that the dimming was meant to indicate the gradual building of a Dyson Sphere, but that seems to assume that the speculated artifact IS a Dyson Sphere, or if it is, that it was just recently under construction.

      I would say that earthlings are not yet an authority on Dyson Sphere project management :-)

      There could well be a natural dimming (if any) PLUS an artifact (or 2 natural processes).

  • DJ Kaplan May 10, 2016, 12:20

    I think that ETC can and should be considered realistically as one of many possible explanations.

    The problem is that many ETC enthusiasts “want to believe” in an alien presence, so they tend to ignore conflicting evidence.

  • Mark Zambelli May 10, 2016, 12:27

    Personally, I find it a wonderful thing to witness this ongoing mystery and to have near realtime responses from researchers. Amazing.

  • Paul Carr May 10, 2016, 12:32

    What we really need is to catch it in the act. So far, no joy, although this might have happened when the star transitioning from morning to evening last Winter. It does seem that several amateur astronomers are keeping a close watch on it, and their measured “B” magnitudes are mostly very consistent with each other, right around 12.38 or so, maybe pls or minus 0.02. They are also observing in other bands, such as V and R.

    I downloaded all the AAVSO’s data to date for the star, which they began collecting last fall. I have it filtered to B in this spreadsheet: https://docs.google.com/spreadsheets/d/1CsuNyFH1bLpZKDvhHCJIoCA7_IZAigY-8eshUeS93vs/edit?usp=sharing

    You can easily download it yourself at http://aavso.org.

    My question is why is this dimmer than the value reported in Boyajian et. al., of 12.26? Is this because the latter accounts for extinction?

    • Michael Hippke May 10, 2016, 15:22

      AAVSO has a different zeropoint compared to the DASCH data, so a different nominal B magnitude is not at all a sign of a dimming.

      The AAVSO data can be extremly valuable, but you have to be extra cautious with it. There is for example a one night-long dip near the beginning, which seems significant. However, in that night two observers provided data, and only one saw a dip, the other had the star as constant. So it’s probably an artefact.

  • James Stilwell May 10, 2016, 12:38

    Seems to me that Webster Cash should be contacted and asked to put KIC 846 on the list of target stars for the exoplanet star-shade launch in 2024. The star -shade is one of the greatest ideas in motion anywhere in science.

    Someone on this site last year mentioned that a planet 11 times the size of Jupiter could account for the 15-22% dips in the star’s light curve. Such a huge planet might have an Earth twin and Mars twin satellites and others accounting for the lesser dips. The star-shade might solve the mystery, and if positive results come might get KIC 846 put on the list of objects to explore for the JWST.

    Mission impossible? Too bad KIC 846 is 1500 ly away. Such is life.

    • Lepton May 10, 2016, 14:13

      Well, who knows! If it’s proved as unfriendly alien home world, maybe 1500ly is not bad after all. :-)

    • Michael May 11, 2016, 3:39

      No planet can get that size unless it is super heated to bloated dimensions and even then it will be evapourating at huge rate, what is more likely is a ringed structure which can block out a lot more light for a lot less mass.

  • Daniel de França Diniz Rocha May 10, 2016, 13:11

    The thing about the dimming of the light and aliens is about them building the Dyson sphere, right? But, with a likely ancient civilization, it’s probable that they had already achieved what they wanted for millions of years.

    But, aside from aliens, what if that is an star with an extremely low period of rotation plus a very short solar cycle. It would be such that plasma would tend to be extremely aligned and catastrophic events of sunspots gathering in many pairs would happen.

    • Harry R Ray May 11, 2016, 9:30

      What most people STILL fail to realize is that if the dimming WAS real, it would make the chances of a non-natural explanation FAR LESS LIKELY! You would have to invoke TWO EXTREMELY CONTRIVED SCENARIOS OPERATING SIMULTANEOUSLY to pull it off! ONE: To build a megastructure THAT QUICKLY(completion time between 15 years and five centuries) would require EXTREMELY RAPIDLY SELF-REPLICATING Von Neumann machines DECONSTRUCTING an entire solar system from rocky planets to Kuiper belts to Oort clouds AND leave ABSOLUTELY NO TRACE OF DUST which would glow in the infra-red. TWO: We would be watching thid at approximately the MID-POINT of the construction project! ET dreamers should actually be OVERJOYED at this result, instead of being so “depressed”! If you remember, I was one of the very few readers(if ANY)who ACTUALLY came to the DEFENCE of HIPPKE when the shtf. NOW, I feel very VINDICATED!

      • Harry R Ray May 12, 2016, 9:36

        KIC8462852 makes one complete rotation every 0.88 days. This is faster than normal, NOT slower than normal.

        • Michael May 12, 2016, 14:58

          For an F- type is surprisingly normal.

      • Nam Nguyen August 26, 2016, 19:12

        Suppose you belong to the Proxima B civilization who don’t have knowledge about electricity but who can build sophisticated optical telescope to have observed the night sight of the Earth for 500 years straight.

        Based the records archived for 500 years, would you say the hypothesis that the recent night light seen on the 3rd planet from the Sun is due to an intelligent life (and not a natural phenomenon) is too contrived, you being a Proxima B scientist in this hypothetical situation?

  • DavidB May 10, 2016, 15:20

    Paul Carr,
    Yes, not properly accounting for extinction
    could be a factor, but also not all blue filters are quite the same.
    There is Blue, and then there are calibrated Blues such as Johnson-Cousin Blue.
    The Blue filters sold to amateurs tend not to be calibrated compared to
    the ones in professional observatories so differences of a tenth of a magnitude can be expected.
    For more information see https://www.astro.umd.edu/~ssm/ASTR620/mags.html

    • Paul Carr May 23, 2016, 15:57

      I am still trying to understand what AAVSO observers do – many of them are very highly regarded, and their director Stella Kafka is a widely published photometric professional. Their APASS catalog is what is used by DASCH. My understanding is that: 1 – when they publish a validated “B” magnitude, that is is the Johnson B, and 2 – they use the APASS catalog for comparison and check stars. It’s not just just a raw photometric measurement, but a relative magnitude vs. the cataloged comparison stars..

  • Keith Cooper May 10, 2016, 17:18

    I don’t have any issues with the conclusions of this peer-reviewed paper, but I do think one problem – and I’m glad this seems to have been recognised by Hippke and company in the process of writing their paper – was that the discussion was initially taking place in the context of pre-prints that hadn’t been peer-reviewed at the time. When this happens it does change the way scientific discussion occurs, and I’m not sure it’s for the best. Laymen in the media take it as gospel and print lurid headlines that veer one way and then the next with each pre-print. More scientifically-minded commentators who might not be experts in this field have no guide to whether anything that is being said in the pre-prints is correct. That’s not to say peer-reviewed published papers can’t be wrong, but they have that added layer of scrutiny. So I’m glad that Hippke and his co-authors have had their paper published.

    The other thing that bothers me is the tone, particularly in the press release that has accompanied the publication of the Hippke paper. I think everyone recognises that the ET hypothesis is a long-shot, but decrying anyone who even considers it as an ‘ET lover’ as the press release does is condescending and unhelpful, while the statement from Hippke that “there are probably no aliens after all” seems misleading to me, implying that refuting the claims of a century-long dip automatically rules out the ET hypothesis, when it does no such thing since the ET hypothesis pre-dates Schaefer’s claims of additional dimming.

    So I’m glad papers are finally getting published on this subject, but it seems to me that hyperbole and soundbites are still ruling the day.

    • Robert G May 11, 2016, 7:29

      As well as learning about the star system, there is also a learning process going on here about how to handle publishing and discussing results in a networked world with a very short news cycle. Think about what has happened here: people have been combing through a fairly big dataset and discovered something strange and suggestive; one of the things which makes it as interesting as it is is the apparent uniqueness of it within the data we have. In the coming years (even just the next 5-10 years), we will find ourselves with datasets orders of magnitude larger, such as Gaia, James Webb, etc., not to mention the Moore’s law effects on radio SETI processing. These will obviously have their own strange outliers as well. If we come across data which looks plausibly like ET it will be a huge news event. Given our increase in capability we are likely to start finding such data again and again. I think we can all draw some conclusions about peer reviewing, preprints, press releases and journalists in a speculative frenzy from how this has played out.

    • Ashley Baldwin May 11, 2016, 15:57

      A very good comment. I think the term “peer review” is a concept alien ( pardon the pun) outside acedemia . Having seen the ensuing arguments it’s easy to see why scientific papers need a “referee”. Falsifiability is the bedrock of good science and also key to separating belief concepts , however well presented , from true science. If you are going to make extreme claims it would be worrying if they were NOT subject to intense scrutiny. That is the scientific method. Not perfect of course but better than believing something because it suits you . I’ve always enjoyed reading arxiv and regretted something similar didn’t exist in own profession of medicine . Having seen this “mystery” unfold I’m not so certain any more . I’m still confident it is a scientific phenomenon causing these mostly real observations . And boy ! Would I like to see it proven as Dyson sphere . That said the multiple comets doesn’t do it for me either. It sounds like something made up to fit the fact after the event rather than the way it should be , the other way round . I always remember that contact binaries are the commonest false positive for Kepler and other transit photometry missions . When something appears that is at first inexplicable the two things that come to mind are either a common thing presenting in an atypical way or else one of many rare things . With this in mind and using Okam’s good old razor Im still going to stick with my initial thought on first reading about this . It’s a contact binary . One that by some means or another is presenting in an odd way. No idea how or why but peer reviewed science has repeatedly shown this so I think I’m on safe ground though I’m happy to proven wrong by something far less prosaic.

      • Eniac May 14, 2016, 12:16

        It sounds like something made up to fit the fact after the event rather than the way it should be , the other way round

        I think it fits perfectly into the scientific method to explain observations after they are made. Yes, in some fields of science (like particle physics), predictions have become so accurate that surprising observations do not happen anymore. That does not mean that this is “as it should be”. Astronomy is still full of discoveries in need of explanation, just like this particular star.

        • Alex Tolley May 14, 2016, 19:38

          The new data coming out of the LHC is sursprising and unanticipated. If it proves out, we will have evidence of new particles that are outside the standard model. We’ll know this year (after the animal “sabotage”). [ Shades of Adam’s pan dimensional beings that look like mice . ]

          • Eniac May 15, 2016, 12:33

            I did not know that. Let’s hope it proves out…

  • Jim Strom May 10, 2016, 23:28

    Good points. Ideally, when a second researcher realizes he or she has results contradicting a first researcher, it would be nice if they kept the good of science in mind and communicated in private, collegially. Don’t journals sometimes publish contradictary results in the same issue? It’s always about finding the truth, and negative contributions can be just as important as positive ones.

    • Robert G May 11, 2016, 10:06

      Absolutely, for actual reviewed and publish-complete papers. Multiple viewpoints on the same information at the same time would provide thoughtful context for journos and their readership.

      For what its worth, I think people working on material like this need to have a careful philosophical moment about preprint servers in particular. If they were publishing results about a new spectroscopic technique for measuring metallicity, it would be one thing. There is something very, very special about discoveries implying alien intelligence though. If confirmed, it would be the biggest news story since sharpened flint. Too many false positives are going to create (earn?) a credibility problem though. This might cause knock on problems on the day some really, really strong evidence comes along.

      I don’t want this to sound too negative though. If astronomers of all people didn’t have their hearts leap into their throats on finding something like this, we might suspect THEM of being extraterrestrial! :)

      • Robert G May 11, 2016, 10:10

        Clarification: when I say ‘too many false positives’, what I meant was, ‘too many gigantic newspaper/newssite media splashes’, not too much discussion of things that might or might not be the real deal.

      • Alex Tolley May 11, 2016, 13:12

        Nasa has been a big abuser of this. Starting with “Life on Mars” ALH84001, and then the major debacle with the “Mono Lake Arsenic using microbes”.

        We have seen the rise of PR storms from institutions hyping lab results that prove less than meets te eye and even later falsified.

        I get why scientists take this approach to ensure they are not scooped, but the result has been a horrible pollution of the scientific method.

        Interesting observations are one thing, but making extravagant claims is another. As has been noted, peer review isn’t anywhere near as good as it should be, but at least it is a check before making claims.

        I agree that the star dimming or not doesn’t necessarily equate with ETI structures. What we do need is more and better observations of the star to characterize it. Rather than alien structures, the explanation might add to the bestiary of objects.

  • Paul Carr May 10, 2016, 23:42

    Yeah it’s been a while since I’ve read a press release that wasn’t a complete waste of bandwidth.

  • Zachary May 10, 2016, 23:56

    Can anyone comment on this claim of an “Apparent May 4 dimming of KIC 8462852”?

    See: https://www.reddit.com/r/KIC8462852/comments/4ik3d2/apparent_may_4_dimming_of_kic_8462852/

    Quote:

    “So the observer is Roger Pickard who happens to be Director of the BAA VSS.

    From Mr. Pickard:

    Interesting that you should pick up on that as the AAVSO queried both sets of observations with me as well (on behalf of the PI).

    No, neither have been confirmed by a third party to my knowledge and I’ve been through both sets of observations myself several times but could find nothing wrong. I’ve never recorded anything quite like that before and I like to consider myself an experienced CCD observer.”

  • Michael May 11, 2016, 1:49

    When I first looked at some of the plates I felt the quality was wanting but it was worth a try. At least the plates digitsation is getting some muuch needed attention.

  • Wojciech J May 11, 2016, 5:24

    I don’t have problem with examining claims and refuting unproven theories.

    However I do have a problem with the tone of the statements in the article. From the start the theoretical possibility of alien technological object is dismissed as silly and improbable.
    By comparing serious search for technosignatures to UFO sightings and decreeing that technosignatures are not probable(without giving any reasons why they aren’t probable), Hippke is contributing to faction in discourse that is rather unscientific in my view(in that it dismisses one theory without any objective reason to do so, besides emotional).

    Sure the argument for this sighting being artificial might be not very strong, but I see no reason for it to be dismissed out of hand and paint it as silly or ridiculous.

    There is also the problem of rejecting any evidence or observations that contradict the assumptions of the author, up to a point where we have a doctrine of interpreting everything as non-technological, and getting to stretched out explanations. Which could become a real problem once we have more advanced telescopes and detection techniques.

    As to the comment “showed no sign of artificial laser pulses, or radio emissions”-why should that be? The idea that advanced civilization ahead of millions of years of us would waste its time beaming radio or laser waves at our planet(which they could have observed since eons) is as much credible as the UFO reports Hippke brings up.

    ” The only somehow realistic astrophysical explanation was offered by Bodman & Quillan, who suggest the presence of a large family of comets, and which as of today are considered to be the “best” explanation.”

    Wasn’t that idea disputed as it would require “648,000 comets – each 200 kilometers or 124 miles wide ” ?

    • Project Studio May 11, 2016, 11:25

      Yes I agree.
      Statistical evidence that trend in the decrease of magnitude over one hundred years is within noise band does not disprove (or prove the trend).
      Even if the ~ .02 decrease in magnitude over one hundred years is an artifact of the plates, it has no bearing on explanations regarding the odd transiting phenomena.
      Yet some comments seem to contend otherwise.

      • Eniac May 14, 2016, 12:20

        Well, the fundamental problem here is that perfectly good explanations exist and the “dimming” was illegitimately used to cast doubt on them in the first place. Now that the dimming is done away with, let’s forget the whole red herring and get back to the comets…

    • Mark Zambelli May 11, 2016, 12:23

      I don’t know what article you refer to but it doesn’t seem to be the one above. There isn’t a mention of comparisons to UFOs at (nor should there be, especially here at CD). Hippke hasn’t been as dismissive as you attest to, so I’m unsure I know where you get that from… infact, I read a measured response to the Schaefer claims, not an overt derision of the (slim) possibilty that the dips are artificial. We are entitled to hold a small chance the dips could be artificial and the article doesn’t say otherwise, as I read it.

  • Sascha Wageringel May 11, 2016, 8:55

    It seems to me, globally, one one hand we have romantics who want to “believe” (mostly public) and on the other hand naysayers who turn down any connection of odd observations to ETI down out of habit (mostly scientific). We are walking a fine line here. We must refrain from jumping to conclusions. I think this is one of the great educational challenges before us.

    I am not too disappointed by these findings because for one i had my hopes not up that much initially. But i am all for investigating such findings. I also would say the “best” explaination is severely lacking for a variety of reasons., but can’t come up with anything better. ETI is still really, really low on the probability list.

    With the Kepler data probability for planets inhabited by life has improved a great deal. And nothing else was to be expected. Why should our system be the great exception? Thist is an extraordinary claim right there.

    We’ll find it and i think we’ll find it soon. Probably not a technological signature but something like the a spectral signature of plants (which is a far more likely calibre than a DS).

    Enthusiasm is nothing bad, but if you really take this seriously you have to accept a “no” and you have to do the observations and do those accurately.

    • Wojciech J May 12, 2016, 4:29

      “Probably not a technological signature but something like the a spectral signature of plants (which is a far more likely calibre than a DS).”
      I believe that this won’t be definitive for some time, as there are many false possible false positives for biomarkers resulting from eccentric natural processes.
      However I believe that if we will start detecting biomarkers(hopefully) then the search for technosignatures will be treated with less ridicule.

  • Harry R Ray May 11, 2016, 10:36

    UPDATE: Schaefer’s initial response to the accepted Hippke paper is that he cannot verify their data, whatever that means.

  • Leonard Hunter May 11, 2016, 12:12

    “The star was unremarkable in the infrared, showed no sign of artificial laser pulses, or radio emissions”

    I would think that neutrino detection would be more revealing as to if there is anything artificial happening. After all even if it is comets, those could be considered to be raw materials being used for an artificial construct.

    • Mark Zambelli May 12, 2016, 15:29

      I’m sure when we develop tech that advanced we could have a look (remember, we’re not that far on from detecting the half a dozen or so neutrinos from SN1987a… and that was a supernova!)… wonder what we’d see?

      • Michael May 13, 2016, 15:18

        A SN emits an enormous amount of neutrinos, a staggering amount, that is the reason why we seen some!

  • John May 11, 2016, 12:17

    What if Tabby’s star is a beacon!? Placed there by aliens to filter out inteligent life and communicate with.

    • Daniel Högberg May 11, 2016, 16:14

      John, thats an interesting theory, even though Im very skeptic.
      Does anybody here know if a mathematician has looked at the dimming sequence in the miniscule chance that some mathematical logic may be present? Prim-numbers perhaps? ;D

      • Harry R Ray May 12, 2016, 9:43

        The ONLY THING IN THE 4 years of flux measurements that might even POSSIBLY be a non-natural transmission of information is what appears to be an EXACTLY 2 to 1 ratio for the INGRESS part and the EGRESS part of the “Q8” light curve, although this is MOST LIKELY JUST A CO-INCEDENCE!

  • Michael May 11, 2016, 14:18

    There is a way that aliens could create a beacon if they had a close in planet that was tidally locked with no atmosphere. If they converted all available light energy on the day side into creating a magnetic field it would create a ion current loop to the star which would in turn generate two hot spots on the star that could be observed at great distances.

  • Andrew Palfreyman May 11, 2016, 15:29

    Has any sort of periodicity been detected in the apparent luminosity? Does the star shine apparently unblocked, and then there’s a period of this crazy stuff, and then again it shines unblocked once again? If so, what’s the period (tells us about the orbital radius of the blocker)? And do the blocking patterns look the same each time around?

  • Paul Carr May 11, 2016, 20:36

    This was at least conceptually considered even before we knew about Tabby’s Star.

    http://arxiv.org/abs/1510.04606

  • Paul Carr May 11, 2016, 20:38

    BTW, folks, there was an intriguing hint last week that Tabby’s Star is still at it. a reliable and experienced observer in the UK saw dramatic dimming over a short time span. However, with only one observer, we can’t rule out equipment problems without more investigation. Be assured that skilled astronomers are on the case.

    • Andrew Norman May 12, 2016, 19:21

      How would that fit with the comet hypothesis? I remember there being some sort of prediction about when we’d see the comets passing in front of the star, again, on an elliptic orbit. Would this fit with those predictions or would it require an even greater number of comets to be hypothesized?

      • Paul Carr May 12, 2016, 21:00

        I don’t know how any of these data fit with the comet hypothesis. I think everyone involved agrees that comets are a lousy hypothesis, but just the only not completely ruled out by the limited data we have so far.

        • Keith Cooper May 13, 2016, 13:38

          I asked Roger Pickard, the observer, and he said the fade was slightly beyond the range seen by Kepler. The star had also returned to normal brightness the following night. The first night he observed it, he says that he did see it slightly fainter than another observer, which he says is odd, but he is a very experienced amateur and really well-respected amongst the UK amateur community, and he stands by his results. I think the more publicity the star gets, the more variable star observers will start following it and hopefully we’ll start to see some corroboration of observations in the future.

          • Paul Carr May 13, 2016, 14:53

            Hopefully, the AAVSO’s photometry experts are investigating. It’s going to be hard to declare a definite, dramatic dimming with only one set of observations.

            I plotted the data here: https://drive.google.com/file/d/0B_LvagsQCx-cSko1RWpTQVpNLXc/view?usp=sharing

            The baseline V magnitude is about 11.85 (as was observed later that day), and although it’s noisy, it seems to drop to about 12.15. This is 31% dimming, which is larger than any even Kepler saw. Why these observations are noticeably noisier than the others I have no idea.

            • EricSECT May 14, 2016, 6:46

              Paul Carr:
              Once again, thanks for the informative “Tabby’s Star for the Perplexed” series on the Wow! Signal podcast. (http://www.wowsignalpodcast.com/). To all: This podcast series is a great format to pass along to friends who are interested but may not have the full background.

              Paul Carr:
              (1) Re: The recent single AAVSO observed 30% dimming: Without digging into the data, I wonder if there are “control” stars that AAVSO monitors as frequently as Tabby’s (and as by as many observers!) so that we might constrain normal scatter by the different observers, perhaps 30% is to be expected. And by a “control” star, I mean a non-variable star, best if of the same F3V class.

              (2) I would like your opinion. Who has had a chance to read Dirk Bontes’ hypothesis on Tabby’s dimming cause?
              https://www.smashwords.com/books/view/632855

              What evidence would disprove Dirk’s idea?

              I think that until we have more data, especially that gathered during the next dimming event, we should concentrate on “natural” explanations, and what we would expect to see as supporting or as contrary evidence. When all the “natural” causes are ruled out…. we are left with the in-explicable.

              Either way it turns out, I eagerly await more data the next dimming event.

              • Paul Carr May 14, 2016, 10:43

                Of course photometry always uses both comparison stars and check stars, and if you download the data you can see how that’s documented. It’s the only way to control for all the variables.

                • EricSECT May 16, 2016, 10:22

                  Paul:
                  Thoughts on Dirk Bontes’ idea?

                  One dimming observation, by one observer, for one night only=Inexplicable. A bad data point.

                  • Paul Carr May 23, 2016, 16:04

                    I haven’t seen any modeling by Dirk Bontes, but I don’t at all see how the Cepheid mechanism can explain Tabby’s Star. Professional modelers would tell you no way is it near the instability “strip” and even if it was, the fact that the star neatly returns to baseline with no overshoot pretty much falsifies that conjecture. there are lots of variable stars within the Kepler field, BTW.

  • DJ Kaplan May 12, 2016, 12:25

    An experiment can only be “disappointing” if you have pre-conceived notions about how it is expected to turn out.

  • David Grinspoon May 13, 2016, 10:52
    • EricSECT May 14, 2016, 7:16

      Excellent article, David Grinspoon. (By the way, do you have a new book out? http://funkyscience.net/home/) We all need to step back, breath deep and talk intelligently and rationally about what we are observing and follow the evidence where ever it may lead.
      Question: Have you read Dirk Bonte’s hypothesis?
      (https://www.smashwords.com/books/view/632855
      Evidence that would support or refute Dirk’s idea?

      One comment on your article at Sky and Telescope: You mentioned “…Whatever the cause of the odd dips in the light from KIC 8462852, it’s clearly not such a Dyson sphere surrounding the whole star.” What evidence refutes a Dyson swarm/sphere? If it is lack of detectable excess infrared (XS IR), consider the following:

      (1) What constraints can we place our our IR detection capability? From Tabby’s, at 1500 ly away….. XS IR could be being emitted, but it’s strength and/or frequency is beneath our detection capability. And/or….Perhaps we ONLY get an IR pulse during a dimming event.
      (2) There is XS IR but it is not detectable because it is direction-ally radiated, away from our line of sight (by an ETI …or a natural cause? Is that even possible?)
      (3) An almost perfect extraction of all available flux energy. Perhaps combined with (1) and (2). There is almost no waste to re-radiate.

      Either way the evidence takes us, it will be exciting next dimming event when AAVSO alerts the big scopes to look closer.

      • David Grinspoon May 16, 2016, 15:16

        Thanks for your comment on my article.
        Yes – I have finished a new book that comes out later this year, entitled “Earth in Human Hands”, it discusses, among other things, the connection between SETI and the Anthropocene (the connection is longevity, and sustainability…) http://www.amazon.com/Earth-Human-Hands-Sapiens-Planet/dp/1455589128

        As for your question about Dyson spheres, swarms, I wasn’t referring to the IR excess but merely the fact that the observed dips don’t seem to be the obvious result of such a structure. One can argue that it might be under construction but it seems very unlikely that we would catch them in the act in that way.

        As I’ve said elsewhere in this thread I don’t see the lack of a secular dimming, if that ends up being the conclusion, as having much bearing on the interpretation of the dips. To me it really says almost nothing about the “alien megastructure” hypothesis, which remains in play, however unlikely.

        Looking forward to learning more from future observations!

  • hiro May 13, 2016, 17:55

    Some artificial rings (1M – 10M km in diameter) around inhabitable rocky planets or some random gas giants orbiting around Tabby’s star from some distance around 10 – 20 AU might be possible and easier to build than a huge ring around the star or a Dyson Sphere. Mining anti-matter not too far from the surface of a star is another possibility too but the process of how is way above my head. However it takes lots of time to verify this “semi-baked postulate”.

  • Rafik Bourne May 15, 2016, 10:13

    “The long-term dimming is alive and well.”

    Can anyone guess who could possibly have said that?

    Looks like other photometry datasets are being analysed and this debate is just hotting up.

    https://www.reddit.com/r/KIC8462852/comments/4jeft1/brad_schaefer_quote_the_longterm_dimming_is_alive/

  • Paul Carr May 15, 2016, 15:04

    Josh Grindlay, PI of DASCH, has stated he’s working on a paper that will set the record straight on the photometry. Whether this will support Schaefer’s thesis I do not know.

  • Harry R Ray May 16, 2016, 9:59

    I just read this on the http://www.phys.org website: “CfA astronomers Mike Dunbar, Glen Pepitas, And Lars Kristensen…used the Submillimeter Array and the James Clerk Maxwell Telescope to search for…dust. They found no signes of it. They can therefore limit the amount of material to…fewer than about eight earth masses throughout the entire system.” To me, this means JUST ONE THING! Eight earth masses of NATURAL dust CANNOT produce a century-long dimming effect for a F3V star! SO: If the “dimming hypothesis is DEFINITIVELY REFUTED to the COMPLETE SATISFACTION OF THE ENTIRE SCIENTIFIC COMMUNITY, Einiac and comets win. If, however, the proposed dimming is proven BEYOND A REASONABLE DOUBT, than the explanation CANNOT BE NATURAL DUST, and either Dirk Bontes wins, or we have FIRST CONTACT! This CLARIFYS things a whole lot, th me anyways.

  • Planetsam/Sam Goodman May 18, 2016, 10:36

    For those who are interested there is now a Kickstarter to fund continuous monitoring of KIC 8462952 by the LCOGT.

    https://www.kickstarter.com/projects/608159144/the-most-mysterious-star-in-the-galaxy

    • Paul Carr May 18, 2016, 15:00

      She very kindly mentions my blog in the writeup, so of course I had to chip in.

      • Harry R Ray May 19, 2016, 9:42

        Paul Carr: I clicked on the website Paul Scott Anderson posted, looked at the LCG to view the 30% “dip”. To my amazement, it looks LINEAR in nature, STARTING at just below 11.8 mags, and then decreasing INCREMENTALLY to 12.2 mags! Does this mean that a WHOLE SERIES of datapoints were taken(and if SO, what IS the number of datapoints taken)showing a swift but INCREMENTAL decrease in luminosity, OR; is thid just an ARTIFACT of the analysis code? RSVP! ALSO: What is YOUR TAKE on the Dunbar et al paper in MY comment posted just above yours and Planetsam/Sam Goodman’s?

        • Paul Carr May 19, 2016, 11:38

          Not sure what you mean by linear in this context. I took a close look at it and it’s quite noisy. I think the smart money is on an instrumentation problem, but too early to dismiss it altogether.

          • Harry R Ray May 20, 2016, 9:34

            What I am SPECIFICALLY asking here, is; did this ONE observer make JUST ONE OBSERVATION, resulting in JUST ONE DATA POINT, which, for some reason appears SMEARED on the graph so that it looks SOMEWHAT linear, OR; did the observer make a SERIES OF OBSERVATIONS OVER THE ENTIRE NIGHT that are represented as a series of POINTS, EACH ONE JUST BELOW THE PREVIOUS ONE, so that ALL OPF THE POINTS APPEAR TO BE LINEAR? If the LATTER is the case, it has HUGE IMPLICATIONS vis a vis the RELIABILITY of the data, which would THEN indicate that KIC8462852 faded THAT ONE NIGHT at the rate of roughly 5% PER HOUR, but then brightened BACK to its original luminosity by the time of the NEXT observation!

  • Paul Scott Anderson May 18, 2016, 18:34
    • EricSECT May 19, 2016, 7:36

      Shades of The Wow! Signal. A dimming event observed at Tabby’s, not corroborated, made by a single individual, even though a fully respected observer. Gotta throw this data point out.

    • Paul Carr May 19, 2016, 14:26

      Here is the clearest plot I could make from the data. The V magnitudes are green, the B are blue, and the red circles are R magnitudes. You can see that everything is back to normal roughly 4 hours later, which is out of family with what Kepler saw. Whatever is causing this, it’s unprecedented in the AAVSO data. BTW, my base epoch was 2457512.5.

      Anyone wants my quick and dirty R script for this, just give me a holler at the Wow! Signal.

      https://drive.google.com/file/d/0B_LvagsQCx-cSWJZckh4ZzN1WTA/view?usp=sharing

  • Paul Carr May 19, 2016, 11:40

    I wouldn’t throw it out until better investigated. Wait and see if it repeats. Viewing of the star is getting better now.

  • Grando Admiraldo Thornax May 19, 2016, 21:57

    I have it on good authority that all the real action is in Fornax. Nice try though, Kepler!

    • Harry R Ray May 20, 2016, 9:38

      Elaborate PLEASE!!!!!!!!!

  • Tom Mazanec May 19, 2016, 22:09

    There is a project you can contribute a few bucks to to monitor this star for its next dimming.
    https://www.kickstarter.com/projects…token=45297e55

    • Michael May 20, 2016, 13:15

      I feel it is moon/s going around a planet that is not transiting the star directly, the moons are orbiting it and are giving off material that forms a temporary disc/ring that occults the star. The moons may be undergoing tidal forces that leads to eruptions like on Io but much much larger. We will have to wait and see what it is but I doubt it is ET, to messy for a construction project.

  • EricSECT May 20, 2016, 15:12

    Thank you!

  • Reinhold Gabloner May 20, 2016, 15:51

    Dear Hippke,
    Why no one ever thought about a bunch of objects in OUR Oort cloud passing coincidentally in the line between our observatory (Kepler) and Tabby’s star? Couldn’t that be the answer for the Kepler data? Maybe if they are large and opaque enough, they could design the star light curve in a way Kepler observed it, without any excess of IR.
    Thx, Reinhold

  • Paul Carr May 23, 2016, 16:06

    There is some new information, but I’m not sure I should share it publicly yet. Suffice it to say that the debate is not over.

    • Paul Gilster May 23, 2016, 16:10

      And more coming up shortly here on Centauri Dreams.

  • Paul Scott Anderson May 23, 2016, 16:12
    • Paul Carr May 23, 2016, 17:16

      The star was too close to the sun to get good observations.

    • Lechuga May 23, 2016, 18:21

      I think Cygnus was blocked by the Sun during that period.

  • JB July 6, 2016, 4:31

    While no astronomer, I am fairly versed in time series analysis. I took the DASCH data for KIC 8462852 and applied an interrupted time-series model with a trend (time) term and a pre/post 1960 term. I did this for the raw dataset, a dataset cleaned similarly to Hippke et al., and a dataset with flagged data removed completely. In every case, the trend term was statistically non-significant while the pre/post 1960 term was significant. While certainly not definitive, these findings support the theory that any differences in brightness over the past century are due solely to a change in equipment around 1960 and not to dimming over time; however, I agree with others that more data are needed. Let me also add that I started these analyses hoping Schaefer was right…

    • Rafik Bourne July 6, 2016, 10:20

      When Dr Schaefer first released his paper I made the same observation.
      There is an apparent step/discontinuity at the time of the Menzel gap.
      A constant gradual long term trend over a Century I think is a poor fit for the data.
      However, we should not automatically assume the sole cause of the discontinuity at the Menzel gap is instruments. Dr Schaefer examined instrument effects in his latest paper by comparing any changes observed for other nearby constant stars. I think he makes a reasonable case that instrument effects/changes during the Menzel gap cannot explain the dimming exhibited by KIC 8462852.
      There could be many causes for the apparent dimming across the Menzel gap, each of which would need to be examined to determine which is most likely. Another possible cause would be an interstellar dust cloud between Earth and KIC 8462852.
      If you examine carefully the two plates included in Dr Schaefer’s latest paper – KIC 8462852 appears to dim compared to most other stars on the plate. However, the star immediately on the right of KIC 8462852 also appears to have dimmed by a similar amount.

  • Paul Carr July 6, 2016, 11:41

    But what about Grindlay’s finding that the Landolt standards exhibit no such behavior?

  • JB July 6, 2016, 19:22

    I should have made it explicit that my findings suggest a significant effect occuring around 1960, but offer no evidence as to what the cause of that effect may be. While an instrumentation effect was the explanation I offered based on my limited knowledge of the data, this is not necessarily the case. There are a number of other possible explanations. The fact that the Landolt standards exhibit no such behavior but that nearby stars do is evidence in favor of an astrophysical effect as opposed to an instrumentation effect. My analysis simply found a step/discontinuity effect at 1960 but no gradual dimming effect. The cause of the effect at 1960 is up for debate. I should have made this more clear.

  • Harry R Ray August 5, 2016, 9:56

    As Schaeffer PREDICTED, t5he long awaited paper by Benjamin T Montet and Joshua D Simon is FINALLY UP ON Arxiv(#1608.01316)! I have ONLY read the abstract but IT IS AN ABSOLUTE SHOCKER: KIC8462852 faded at a rate of TWO PERCENT PER YEAR over the ENTIRE FOUR YEARS OF THE PRIMARY MISSION!!! At this rate, KIC8462852 will no longer be observable in visible light in JUST FIFTY YEARS. I can’t wait for Schaffer’s take(and Hippke’s REBUTTAL-if there IS one)on this!

  • Harry R Ray August 5, 2016, 10:08

    OOPS: Got a little carried away. The TOTAL fade over the 4 years was 3.5%. This would mean an eighty seven point five percent fade in the NEXT CENTURY, and a COMPLETE FADE-OUT in LESS than a century and a half.