IAU: COROT’s Unusual Catch and More

by Paul Gilster on May 26, 2008

Yesterday’s high-tension arrival on Mars raises inescapable thoughts about future missions. Even the fastest spacecraft we can build today take years to reach the outer planets (New Horizons won’t reach Pluto/Charon until 2015), and targets deep in the Kuiper Belt, much less the Oort Cloud, conjure up potential missions longer than a human lifetime. Imagine the arrival of a robotic interstellar probe around, say, Epsilon Eridani, not a few years after launch, but a few generations. How would the team feel that took that final handoff from previous researchers, people who had invested their lives in a mission whose end they knew they would never see?

Thus we make the segue back into interstellar matters, with today’s Phoenix operations still very much in mind. And I want to go quickly to the recent COROT announcement, for the doughty spacecraft has been hard at work observing its sixth star field, a sweep of some 12,000 stars that began in early May. The team presented two new planets at the IAU symposium on transiting planets in Boston, which just concluded on Friday the 23rd. Both are gas giants in the ‘hot Jupiter’ category, but two other COROT objects are even more interesting (and thanks to Vincenzo Liguori for another early heads-up on COROT news).

For the object called COROT-exo-3b may well be a cross between a brown dwarf and a planet. With a mass some twenty times Jupiter’s (based on ground-based follow-up observations) and a radius somewhat less than Jupiter’s, it is said to be twice as dense as platinum. Another potential signature may mark the existence of an exoplanet a mere 1.7 times Earth’s radius, although that one has yet to be confirmed.

Based on all the Boston results, you have to believe that what Greg Laughlin calls ‘transit fever’ is catching hold. Here I have to quote the UC-Santa Cruz astronomer, recently back from the abovementioned IAU meeting. Calling this the most exciting conference he ever attended, Laughlin adds:

Planetary transits are no longer the big deal of the future. They’re the big deal of the right here right now. Spitzer, Epoxi, MOST, HST and CoRoT are firing on all cylinders. The ground-based surveys are delivering bizarre worlds by the dozen. And we’re clearly in the midst of very rapid improvement of our understanding of the atmospheres and interiors of the planets that are being discovered.

The HARPS planet survey alone, tracking solar-type stars of classes F, G and K, has not only been accumulating data and tightening the profiles of existing planets, but has forty-five additional candidates in the hopper, not counting red dwarf possibilities. I’ve often said that we are in the golden age of planetary discovery, but it’s clearly an age that is only beginning as we not only tighten up our transit methods but improve our radial velocity techniques to find ever less massive worlds. Can a terrestrial-class world around a Sun-like star be that many years away?

John Hunt May 26, 2008 at 17:08

> Imagine the arrival of a robotic interstellar probe around, say, Epsilon Eridani, not a few years after launch, but a few generations. How would the team feel that took that final handoff from previous researchers, people who had invested their lives in a mission whose end they knew they would never see?

I really don’t see NASA or anyone else constructing an interstellar mission that would take generations to complete if the purpose is only for science return. The straight forward reason for this is because, after the launch, technology will advance to the place where, in a few years, we’ll be able to produce a yet faster craft which would overtake the previous craft. So the Wait Equation will dictate when we’ll launch such a mission.

However, this all changes if the purpose for the interstellar mission was not for science return but for the “preserving of humanity” by including components (e.g. frozen embryos, stem cells, etc) which could produce humanity upon arrival.

In this case the team and countries launching such a mission wouldn’t care so much about getting back science return within the lifetime of the team but rather just successfully launching the craft in order to produce an “insurance policy” for humanity. If we destroy ourselves with grey goo, a super virus, a stable black hole, or Terminators, at least humanity still has a chance of surviving in the form of that interstellar mission. The Wait Equation would not apply since insurance is still considered a good buy even if catastrophy didn’t happen.

Also, if you are going to be spending billions, for which purpose would you rather spend it:
– to “insure the survival of humanity” or
– to “get a close look at yet another planet”?
There is no fundamental imperative for the second but there is for the first.

> Can a terrestrial-class world around a Sun-like star be that many years away?

I think that we all agree that the answer is an enthusiastic, “No”! And this moment will probably mark the beginning of a growing movement for an interstellar mission.

But this opens an interesting question. When we find this planet how far away will it be? If COROT has surveyed 72,000 or so stars and hasn’t yet found our planet, when it is finally found, how far away will it be? I’m thinking it might be 50+ light years away. For an interstellar mission, this is a tremendous distance. And when future missions find more such planets, how far will be the first one that has oxygen or methane in it’s atmosphere or shows a photosynthetic signature? It could be 100+ or more light years away. It would be very difficult to convince NASA, et al to launch a science mission to that distance and time.

However, we’ll likely discover nearby Mars-like planets or semi-habitable moons around large planets. Given what we’ve got in our solar system, I bet we’ll find a planet or moon with frozen water ice within 10 light years. For an interstellar mission, this might be our target.

Administrator May 26, 2008 at 18:30

John, re waiting for faster transport, you might enjoy “Barnard’s Star and the ‘Wait Equation,’” originally posted here:

http://www.centauri-dreams.org/?p=915

All about when to launch, with reference to some earlier work (and, of course, to the A.E. van Vogt classic “Far Centaurus”).

One scenario for a multiple-generation robotic mission: The delivery of an assembler package that could set up a full-fledged observatory within the destination star system — imagine a system with a particularly interesting Earth-like world. You’re right that a basic science-based flyby wouldn’t make sense given the progress we’re making in observing exoplanets, unless transport gets quite cheap (highly dubious!). But I can think of other scenarios for waiting out the long trip.

Adam May 27, 2008 at 6:11

Hi All

It’s a bit odd how they’re making out a 20 Jupiter mass brown dwarf out to be somehow freakish – modelling of brown dwarfs has shown them to be denser than platinum for years. Heck even 0.1 solar mass red dwarf stars are denser than platinum. I suppose the unusual way it was found – by transit, not by optical imaging – is news-worthy, but there will be more to come.

dad2059 May 27, 2008 at 6:38

Mr. Hunt makes a valid and interesting point that’s probably very obvious and one I don’t think of when we have discussions about interstellar missions.

Must be that touch of 11 year-old kid I still have in me. I like adventure for adventure’s sake!

Danlo May 27, 2008 at 7:03

Have we realy checked our closest neighbouring stars enough?

I remember reading a book (don´t remember either the name of the book or the author, but maybee it was Arthur :)) where they discovered a habitable planet around a close red dwarf I think. The planet had not been seen before because of an interstellar cloud (or something like that) and the common red dwarf-star had never been payed much attention.

I think they referred to the star as “Lucifer” in that book.. anyone else read it?

Administrator May 27, 2008 at 8:27

Adam, agreed — what’s interesting here is the possible ‘missing link’ between brown dwarf and planet idea, rather than the density itself.

andy May 27, 2008 at 8:34

I think the issue is that even when taking compression into account, a 20 Jupiter mass brown dwarf is predicted to be larger than this object: COROT-Exo-3b’s radius is too small.

James M. Essig May 27, 2008 at 15:58

Hi Folks;

This is another great discussion.

It occurred to me and others before I was even born that non-relativistic huge manned space craft could be used to send humanity out all over the currently observable universe.

Take for instance a craft with a terminal velocity of only 10s to 100s of kilometers/second. The craft could be huge, on the scale of a small planetary moon and set rotating for artificial gravity. A huge non-volatile supply of nuclear fusion fuel could be carried on board for nuclear fusion generated electrical power to power the station. A dewar style layered arrangement of electromagnetic energy reflecting materials could reduce the radiative losses to space. The craft could be constructed of materials of extreme strength such as carbon fiber reinforced materials or even from carbon nanotubes.

The craft could have micropods or small ships that would drop off humans to various worlds as the craft passed by or in proximity to these planets.

Assuming maximum craft velocities of 0.001 C, the crafts could be used to populate regions of our universe with a radius of 10 million LY in 10 billion years. If we are lucky enough to eventually see a slowing of the expansion rate of our universe, in one trillion years, we could populate out to 1 billion LY.

Such an undertaking would be done in part for spiritual reasons and would be a huge undertaking of future human civilization. I think that as we reach out and explore our solar systems planets and moons with robotic space craft, along with anticipated profound discoveries, the whole human race is going to come down with cabin fever and a wonderllust to reach out and explore ever further abroad. The Phoenix probe may be just what is required to jump start all of this.

Thanks;

Jim

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