Photo of Wes Traub and Steve Unwin
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In a wonderful surprise, the Geneva planet-hunters announced their discovery of an Earth-mass planet orbiting alpha Cen B, a member of the triple system that, at 1.3 pc, is our nearest bright-star neighbor. The planet, alpha Cen Bb, has an m*sin(i) value of 1.13 Earths, and a period of 3.2 days, so it is certainly terrestrial, but it is not habitable-zone material. The detection was made with the HARPS spectrograph in Chile, measuring an amazingly small semi-amplitude of 0.51 m/s. See http://www.nature.com/nature/journal/v491/n7423/full/nature11572.html for details.

Good surprises abound: Olivier Guyon was selected as one of 23 MacArthur Fellows, for his work in "designing telescopes and other astronomical instrumentation that play a critical role in the search for Earth-like planets". The announcement tells you a lot about his professional activities, but to learn about his hobby of casting and polishing telescope mirrors in his backyard in Hilo, you will have to ask him personally.

The Long Beach AAS meeting will have 5 invited exoplanet talks, including 3 prize lectures:

  • Natalie Batalha, "Finding the Next Earth", Plenary lecture, Tues. 8 Jan., 8:30am;
  • Heather Knutson, "Exploring the Diversity of Exoplanetary Atmospheres", Annie Jump Cannon Award lecture, Tues. 8 Jan., 11:40am;
  • John Johnson, "Hot on the Trail of Warm Planets Orbiting Cool M Dwarfs", Newton Lacy Pierce Prize lecture, Tues. 8 Jan., 2:00pm;
  • Eric Ford, "A New View on Planetary Orbital Dynamics", Warner Prize lecture, Wed. 9 Jan., 11:40am;
  • Michael Jura, "The Elemental Compositions of Extrasolar Planetesimals from Spectroscopy of Polluted White Dwarfs", Plenary lecture, Wed. 9 Jan., 3:40pm.

    Congratulations to Natalie, Heather, John, Eric, and Michael!

    There are many other exoplanet events of interest at the Long Beach meeting, so don't forget to check the meeting schedule.

    On a good-news roll, Kepler entered its Extended Mission phase, looking to cap off the first 3.5 year mission with an additional 4 years. Most of the 7.5-year span will be needed if Kepler is to fully sample the habitable zone, which for the Earth-Sun system would take a statistical minimum of 3.5 years of observing, but to go out to Mars, say, would take 3.5*1.52^1.5 or 6.6 years. Let us hope that none of Kepler's three remaining reaction wheels become squeaky wheels, because we have no way to get an astronaut out there to oil them.

    And on the topic of telescopes, NASA announced, and selected in quick order, a Science Definition Team to study astrophysical options for a WFIRST science mission using one of the recently-acquired 2.4-m telescopes, with the same science goals as for the original WFIRST study, but in this case to add an option for an exoplanet direct-imaging coronagraph. The charter for the SDT is at http://exep.jpl.nasa.gov/documents/charter-signed.pdf , and up to date information on its activities is at the WFIRST homepage. The baseline mission to be studied is called the Astrophysics Focused Telescope Assets (AFTA) Design Reference Mission (DRM), and the SDT's report is to be delivered by the end of April 2013.

    To be sure that no asteroid is left unturned, NASA has also announced that it would like to hear other ideas for the use of a 2.4-m telescope, this time from anyone who wishes to submit their thoughts, but on a very short timetable: by 7 January 2013; if this newsletter reaches you before then, there is still time to respond. Details are at http://science.nasa.gov/salso/request-information/ . Oh yes, the name of the brief study that will follow is Study on Applications of Large Space Optics (SALSO), easy to pronounce, but more easily mixed up with a Cuban dance or a tomato-jalapeno dip.

    The CoRoT mission appears to have come to an end, with a computer failure, as reported in Nature. CoRoT was launched in 2006, and has discovered 31 confirmed exoplanets, and about 200 candidates; a dramatic accomplishment. CoRoT also pursued the technique of using stellar oscillations to characterize a star's interior, which was in fact its original purpose, to which exoplanet transits were added before launch. Rest in peace, CoRoT!

    Finally, a sobering report from Santerne et al., writing in A&A recently, citing their RV observations of 46 Kepler candidate planets, all short-period giants, and finding that 35% of these are false positives, e.g., background eclipsing binaries or other objects, but not bona-fide exoplanets. A commentary in Nature summarizes the story.