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NEOWISE: New Data Release, Implications

The Wide-field Infrared Survey Explorer (WISE) has been featured often in these pages, usually in terms of brown dwarfs and the possibility of uncovering a small star or brown dwarf closer than Proxima Centauri. But while we still have no evidence of such, we do have abundant data on brown dwarfs, as well as a useful compendium of objects that come close to the Earth.

For WISE, launched in 2009 and placed into hibernation in 2011 upon completion of its primary mission, was reactivated in 2013 as NEOWISE. The goal is now the observation of asteroids and comets both near and far by way of characterizing their size and composition.

Amy Mainzer (JPL), NEOWISE principal investigator, points to the mission’s success:

“NEOWISE continues to expand our catalog and knowledge of these elusive and important objects. In total, NEOWISE has now characterized sizes and reflectivities of over 1,300 near-Earth objects since the spacecraft was launched, offering an invaluable resource for understanding the physical properties of this population, and studying what they are made of and where they have come from.”

The WISE/NEOWISE archive is publicly available through IRSA, the NASA/IPAC Infrared Science Archive. The animation below shows detections during NEOWISE’s four years of operation under the current mission parameters. All told, 2.5 million infrared images were collected during the fourth year and are now combined with the prior three years of NEOWISE data in the archive. 10.3 million sets of images are available, and a database of more than 76 billion source detections extracted from those images. The April, 2018 NEOWISE data release can be found here.

Image: This movie shows the progression of NASA’s Near-Earth Object Wide-field Survey Explorer (NEOWISE) investigation for the mission’s first four years following its restart in December 2013. Green dots represent near-Earth objects. Gray dots represent all other asteroids which are mainly in the main asteroid belt between Mars and Jupiter. Yellow squares represent comets. Credit: NASA/JPL-Caltech/PSI.

Obtaining measurements of the diameters and albedo of near-Earth objects through infrared observation, NEOWISE has, in its four years of tracking asteroids and comets, scanned the skies a total of eight times, observing 29,375 objects, a total that includes 788 near-Earth objects and 136 comets since the WISE to NEOWISE transition. Ten of these objects have been classified as PHAs, or potentially hazardous asteroids, based on both their size and the proximity of their approach to Earth’s orbit. In fact, the first PHA found by WISE was 2013 YP139, discovered a mere six days after observations resumed in December, 2013.

We’re now well into the ninth sky coverage period for NEOWISE, with the mission extended through June of 2018. Although potentially hazardous asteroids obviously get greater attention, not all of the mission’s news has been made among this population. In mid-2017, for example, we learned that mission scientists had found about seven times more long-period comets measuring at least one kilometer across than had previously been predicted. Long-period comets take more than 200 years to complete a single revolution of the Sun.

That was a finding with interesting implications:

“The number of comets speaks to the amount of material left over from the solar system’s formation,” said James Bauer, lead author of the study and now a research professor at the University of Maryland, College Park. “We now know that there are more relatively large chunks of ancient material coming from the Oort Cloud than we thought.”

Although discovered in the NEOWISE era, the paper on this work actually draws on data produced during the original WISE mission, an example of how the spacecraft continues to let us examine objects both near and far, including those that have been perturbed out of their orbits in the Oort Cloud, pristine material from the Solar System’s era of formation. That there are so many more long-period comets than predicted would seem to reinforce the idea that cometary delivery of icy materials from the outer Solar System must have been common.

The paper on the long-period cometary population is Bauer et al., “Debiasing the NEOWISE Cryogenic Mission Comet Populations,” Astronomical Journal Vol. 154, No. 2 (July 2017). Abstract available.


Comments on this entry are closed.

  • Harry R Ray April 24, 2018, 9:51

    Talking about new data releases and “implications”: “SETI with GAIA: The observational signatures of nearly complete Dyson spheres.” by Zacrisson E., Korn A., Wherhahn A., Reiter J. TYC 6111-1162, a F(6-9)dwarf star’s spectroscopic distance is TWICE that derived from itd CURRENT(i.e. PRE-tommorow)Gaia parallax. NATURAL EXPLANATION: Astrometric solution has been compromised by an unseen binary companion like a white dwarf near the neutron star mass threshold(i.e.~1 Msun): NON-NATURAL SOLUTION: NEARLY COMPLETE DYSON SPHERE! HST should be able to detect such a white dwarf with its STIS UV instrument. ALSO: Fermi is HOPEFULLY)temporarily down, but Swift and Chandra MAY be able to detect X-ray emission from such a putative white dwarf star, should it actually exist.

    • Michael C. Fidler April 24, 2018, 10:28

      It’s just an intergalactic wormhole surrounded by a Dyson Sphere made to look like a F6-9 Dwarf!!!

    • Harry R Ray April 24, 2018, 10:36

      Sorry, I meant TYC 6111-1162-1. ALSO: The http://www.reddit.com/r/KIC8462852 sub-reddit folks have ALREADY OPENED a sub-reddit for THIS STAR, so they must think that it is a REALLY BIG DEAL! Not me, but we’ll just have to wait and see.

      • ljk April 24, 2018, 11:57


        SETI with Gaia: The observational signatures of nearly complete Dyson spheres

        Erik Zackrisson, Andreas J. Korn, Ansgar Wehrhahn, Johannes Reiter

        (Submitted on 23 Apr 2018)

        A star enshrouded in a Dyson sphere with high covering fraction may manifest itself as an optically subluminous object with a spectrophotometric distance estimate significantly in excess of its parallax distance.

        Using this criterion, the Gaia mission will in coming years allow for Dyson-sphere searches that are complementary to searches based on waste-heat signatures at infrared wavelengths. A limited search of this type is also possible at the current time, by combining Gaia parallax distances with spectrophotometric distances from ground-based surveys.

        Here, we discuss the merits and shortcomings of this technique and carry out a limited search for Dyson-sphere candidates in the sample of stars common to Gaia Data Release 1 and RAVE Data Release 5.

        We find that a small fraction of stars indeed display distance discrepancies of the type expected for nearly complete Dyson spheres.

        To shed light on the properties of objects in this outlier population, we present follow-up high-resolution spectroscopy for one of these stars, the late F-type dwarf TYC 6111-1162-1.

        The spectrophotometric distance of this object is about twice that derived from its Gaia parallax, and there is no detectable infrared excess. While our analysis largely confirms the stellar parameters and the spectrophotometric distance inferred by RAVE, a plausible explanation for the discrepant distance estimates of this object is that the astrometric solution has been compromised by an unseen binary companion, possibly a rather massive white dwarf (≈1 M ⊙ ). This scenario can be further tested through upcoming Gaia data releases.

        Comments: 9 pages, 4 figures; comments welcome

        Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

        Cite as: arXiv:1804.08351 [astro-ph.SR]
        (or arXiv:1804.08351v1 [astro-ph.SR] for this version)

        Submission history

        From: Erik Zackrisson [view email]

        [v1] Mon, 23 Apr 2018 11:49:47 GMT (339kb)


        We are like ants at a human construction site, with barely a clue as to what is going on around us or why.

        • Harry R Ray April 25, 2018, 9:22

          “we are like ants at a human construction site, with barely a clue as to what is going on around us or why.” To find out JUST HOW TRUE this statement is, check out Ben Montet’s(of Boyajian’s Star fame)latest tweet.

        • Harry R Ray April 25, 2018, 9:26

          OOPS: Not the latest anymore. Scroll down to his April 19 tweet.

          • ljk April 25, 2018, 11:30

            I presume you mean this one:

            Ben Montet‏ @benmontet · Apr 19

            What? A claim of a *188 YEAR* (not a typo) rotation period in Przybylski’s star?! What? How?



            • Harry R Ray April 26, 2018, 9:18

              You betcha! Actually, this one may not be THAT UNunderstandable(have I just created a NEW WORD here?). A comment posted on the http://www.reddit.com/r/Przybylski‘s Star sub-reddit states that ANOTHER HIGHLY MAGNETIZED star appears to have a 50 year rotation rate. However, after HOURS of searching on the internet, I have yet to find remarks of any kind concerning it, let alone the star’s official designation. Help, anyone?

    • Antonio April 26, 2018, 8:29
  • Michael C. Fidler April 24, 2018, 10:11

    It is fascinating that 65 million years ago the most intelligent species were wiped out by a long period comet that shook the earth to its core. Within less then one and a half percent of the age of earth we have evolved to the level of understanding to what is required to keep us and the earth safe from this happening again. Could mass extinctions be the only way life can evolve to advanced intelligence?

    00.01445 x 4,500,000,000 years = 65,025,000 years

    • ljk April 24, 2018, 12:43

      That is very interesting to note, but it makes me wonder why all the previous mass extinctions on Earth did not produce another highly intelligent species?

      Or did they….


    • Robin Datta April 25, 2018, 17:28

      Mass extinctions prune the tree, making way for new branches. It takes a lot of specific factors acting together to allow the synergistic development of intelligence and the capability for its expression.

      There were four mass extinctions on earth prior to the one that ended the time of the dinosaurs. As far as we know, those four extinctions were not followed by the evolution of civilization-building intelligence.

      • ljk April 26, 2018, 9:30

        This is why we so badly need to find extraterrestrial life. We only have data points from one planet so far.

        So does it take five mass extinctions to create an intelligent, tool building and using species on a terrestrial type planet? Or is Earth the exception and not the rule?

        And how about the evolution of life in general? Does it also take several billion years to go from microorganisms to complex multicellular creatures? Or again is Earth the exception and life elsewhere has evolved even faster? Or slower?

      • Michael C. Fidler April 26, 2018, 10:14

        Yes, but the point is the dinosaurs were not fast enough or small enough or smart enough to hide and take over the earth. Each time a mass extinction has taken place something new and better comes along. This may be the case on other exoplanets also so eventually intelligence species should evolve. Still cannot see a short arm T-Rex flying a starship, but you never know!

  • Bob April 24, 2018, 13:33

    Has there been any discussion of leveraging NEOWISE in the search for Batygin and Brown’s ninth planet? I assume it’s been pointed in the plane of the ecliptic, so the data taken to date would not be applicable. It would need to be dedicated to the portion of sky proposed by Batygin and Brown. But is this outside the scope of a possible second extended mission?

    • John walker April 24, 2018, 14:47

      Negative results of Catalina Survey and Panstarrs data analyses suggest Planet 9 to be near its apoapsis and beyond (NEO)WISE detection limit. https://2.bp.blogspot.com/-_LyEwG4UkPQ/Vp_6haMekPI/AAAAAAAANpw/6ocvJi6yqi8/s1600/Capture.PNG

      • ljk April 25, 2018, 9:21

        Would TESS be able to do anything about finding Planet X either during its current run or in an extended later mission?

        • John walker April 25, 2018, 14:45

          No. Same reason. Too faint. Batygin and Brown themselves are using the 8meter Subaru Telescope to search. Regarding Planet 9 a note of caution, recent simulations and the OSSOS Survey suggest B&B’s central claim of TNO periapsis clustering may actually be a result of observation bias.

  • Michael C. Fidler April 26, 2018, 11:18

    Something that makes me wonder on asteroids and comet impacts to earth – the last large one may have only been some 13,000 years ago. The latest count is 180 craters on land but there would of been three times (540 more!) impacts in the oceans. Started looking around and found a study of a large ocean impact feature next to the Falkland islands, then found another report of possible impact causing the unusual Drake Passage and very volcanically active South Sandwich Islands arc. This caused the freezing over of Antarctica from when the land bridge to South America was destroyed and the Antarctic Circumpolar Current (ACC) was established 33 million years ago.
    Even the Chicxulub crater caused major changes on the opposite side of the Earth due to Antipodal focusing of seismic waves. So what would large impacts cause in the thin Oceanic crust? It would be very interesting to model a large super earth with a oceanic ridge system and see how over time large impacts would rework its structure. The thin floating crust would cause a large rock tsunami to expand out from the impact – not just the ejecta from the comet but the seismic wave that would be generated and the Antipodal focusing of seismic waves on the opposite side of the planet. Could many of the volcanic systems, fault systems and large arcs systems ) observed on earth’s oceans and continents be the result of large asteroids and comets impacts that reshaped the surface geologic structure of our planet?


  • Gary Wilson May 6, 2018, 14:50

    What then, is the central project of our civilization? I don’t believe we have one. But the most important project of our civilization may well become spacefaring as a way of bringing in the necessary materials to sustain life on a biologically degraded planet. Care for the planet should be the central project of our civilization but we haven’t reached the level of maturation necessary to understand that as a species. We arose as a hunter gatherer species and developed technical skills necessary to vastly increase our population, but no concurrent maturation of the understanding our impact on the planet occurred. Spacefaring cannot provide a route to maturity, conservation and preservation of the Earth.

  • ljk June 15, 2018, 9:57

    Two years of stonewalling: What happened when a scientist filed a public records request for NASA code.

    Retraction Watch readers may know Nathan Myhrvold, who holds a PhD in physics, as the former chief technology officer at Microsoft, or as the author of Modernist Cuisine. They may also recall that he questioned a pair of papers in Nature about dinosaurs. In that vein, he has also been raising concerns about papers describing the sizes of asteroids. (Not everyone shares those concerns; the authors of the original papers don’t, and astronomer Phil Plait said Myrhvold was wrong in 2016.)

    Last month, Myhrvold published a peer-reviewed paper as part of his critique. The final version of that paper went live today, as did a story about the science in The New York Times and a detailed explanation by Myrhvold in Medium. As the discussion over the results continues, here he shares his experience trying to obtain details about the methodology the authors used.