By Wes Traub
Exoplanet science took several big steps forward this quarter, with the number of planets and candidates now totaling over three times the number we had a year ago. Exoplanet planning for future missions also entered a new phase with the startup of a science definition team for WFIRST, and community decisions to actively prepare for a mid-decade review in 2015 leading to an exoplanet direct imaging mission in the 2020s, as recommended by Astro2010. Here is my view of these and other events of note…
The ExoPAG had a decisive meeting, ExoPAG-3, on the weekend before the January AAS. (Recall that ExoPAG stands for Exoplanet Exploration Program Analysis Group.) We heard a lot of soul-searching talks and comments on the recommendations of Astro2010 regarding exoplanets, and in particular how the exoplanet community should present itself at the mid-decade point (~2015) when the DSIAC (Decadal Survey Implementation Advisory Committee) will meet to decide on mid-decade adjustments to the current plan, including any recommendation for ramped-up technology development for the expected exoplanet direct-imaging mission in the 2020s. The community present at ExoPAG-3 made a key decision to focus near-term efforts, from now until 2015, on two types of direct-imaging systems, internal and external coronagraphs. Interferometers are not to be considered in the 2015 down-select of direct-imaging techniques. Two SAGs (study analysis groups) were initiated in these areas, the Coronagraph and Starshade SAGs. In support of this group decision, the Exoplanet Exploration Program stated that it will plan to fund two DRM (design reference mission) studies in FY13, one each for internal and external coronagraphs, with two ISWGs (Interim Science Working Groups) to be competitively selected and funded by the end of 2012; this announcement was met with widespread approval by those present. Accordingly, another SAG was commissioned to generate the science requirements for the 2020s mission, and to draft ground rules of the DRM studies. The notional schedule is this: concept studies begin in January 2013; concept study reports completed and submitted to NASA in January 2014; Senior Review of the reports, including face to face discussions with the panel, in summer 2014; Senior Review panel submits report to NASA summarizing their findings and recommendations for the architecture downselect, December 2014; this report and the resultant NASA decision sent to the DSIAC, in 2015.
A second important decision at the ExoPAG meeting was to formally work with the traditional UVOIR (ultra-violet, optical, infrared) community to jointly define a telescope that could serve the interests of both groups in the 2020s. Several ExoPAG members met with the newly-appointed COPAG (Cosmic Origins Program Analysis Group), after ExoPAG-3, to initiate discussions on a joint approach to a telescope for the 2020s. A second face-to-face meeting of subgroups from the ExoPAG and COPAG are tentatively scheduled to start serious work on the telescope issue in early May. Watch the ExoPAG web site http://exep.jpl.nasa.gov/ExoPAG/ for details, and plan to participate if you can help address the issues.
On a pure science note, I am happy to report that the long-awaited paper on the results of the Keck Interferometer Nuller observations of exozodi emission from around some two dozen nearby stars was submitted to the ApJ in January. Rafael Millan-Gabet is the lead author, with 10 co-authors.
The second release of Kepler data, another much-anticipated paper, was made public a few days later, in early February. This paper lists 1235 planetary candidate, around 997 host stars, from the first 4 months of observing. Bill Borucki is the lead author, with 65 co-authors.
The most dramatic finding from the Kepler data is the 6-planet system transiting Kepler-11, all packed into a radius of 0.46 AU. Jack Lissauer is the lead author, with 38 co-authors.
The EChO (Exoplanet Characterization Observatory) proposal was chosen by ESA, as one of four candidates, in its first Assessment Phase downselect toward its third (M3) medium-class mission. A total of 47 proposals were submitted. The PI is Giovanna Tinetti, at University College London. The competition for the M1 and M2 slots, between Euclid, PLATO, and Solar Orbiter, will be decided by ESA in October this year.
Meanwhile, WFIRST is being pursued in the US, with the SDT (Science Definition Team) having been selected in December 2010, and meeting face to face in January (at GSFC) and March (at NExScI in Pasadena). (Recall that WFIRST stands for Wide-Field Infrared Survey Telescope.) The WFIRST SDT is chartered with the difficult tasks of generating an interim report by June 2011 on two topics: (a) a DRM for a WFIRST mission that assumes Euclid is selected by ESA and launches in this decade; and (b) a preliminary framework for negotiation with ESA a combined WFIRST/Euclid mission that accomplishes all the goals of WFIRST and Euclid. A final report is requested of the SDT in 2012, reflecting ESA’s decision on Euclid.
Science and society got reacquainted again, briefly, at the AAAS meeting in Washington DC in February. At a well-attended 3-hour session on a Sunday afternoon, Jennifer Wiseman (splitting her time between GSFC and the AAAS) led a session to consider the effect on society, including the major religions, of the discovery that life exists on a nearby exoplanet. Opinions were split between those that thought it would be a “Copernicus moment”, and those that thought most people already believe in aliens and angels.
There are two exoplanet meetings of general interest coming up soon. “Signposts of Exoplanets” (i.e., debris disks and exozodi disks) is 12-14 April at GSFC, organized by Marc Kuchner, with information at http://science.gsfc.nasa.gov/667/conferences/signposts.html . And “Exploring Strange New Worlds: From Giant Planets to Super Earths” will be held on 1-6 May in Flagstaff, organized by Chas Beichman and friends from NExScI and ExEP (you know by now: the NASA Exoplanet Science Institute, and the Exoplanet Exploration Program). The URL is http://nexsci.caltech.edu/conferences/Flagstaff/.