Spitzer Space Telescope Mww-1 Warm Spitzer and Astrobiology Presented to NASA Astrobiology Institute Planetary System Formation Focus Group Michael Werner Spitzer Project Scientist JPL/Caltech January 7, 2009

Spitzer Space Telescope Mww-2 What is Warm Spitzer? Around mid-April, 2009, Spitzer’s liquid Helium cryogen will be depleted The telescope will quickly warm up to ~25-to-30K. –At this temperature, IRAC Bands 1&2 at 3.6 and 4.5um should operate with unchanged sensitivity –Telescope should still be in focus, with no loss of image quality After a ~six-week checkout period, we will begin the Warm Spitzer science mission with IRAC Bands 1+2 –We are currently approved for the first 2 years of this program –10,350 hours of large Exploration Science programs have been selected for execution during these two years. Additionally, 300 hours of discretionary time are allocated to exoplanet studies –1500 hours of smaller GO programs for the first Warm Mission year will be selected following proposal submission in February 2009 We will present to the 2010 Senior Review the case for continuation of Warm Spitzer until its [communication-limited] end of life at the end of 2013

Spitzer Space Telescope Mww-3 How Warm Spitzer Addresses Astrobiology Goals Astrobiology Goal #1 – (Habitable Planets) – is addressed directly by two selected programs: –Detecting the Transits of Nearby Super-Earths PI M. Gillon, Geneva University (100 hours) –Confirmation and Characterization of Kepler Mission Exoplanets PI D. Charbonneau, Harvard (800 hours)

Spitzer Space Telescope Mww-4 Detecting the Transits of SuperEarths Objective: Identify SuperEarths which transit nearby, bright stars Starts with the HARPS data base [K<7;now approaching 40 and growing] of solar type stars with radial velocity planets having minimum masses in range 2-20 Earth masses and probabilities ~2.5-to-15% of being in transiting orbits. Will observe best candidates with Spitzer hoping to detect 2 +/1 transits. If transit is detected, net result will be direct determination of size, mass, density, and perhaps – via models - composition of Super Earths. Identified planets will be natural targets for JWST spectroscopy to study atmospheric composition.

Spitzer Space Telescope Mww-5 Confirmation and Characterization of Kepler Mission Exoplanets Objective: 1. Study atmospheres of new classes of exoplanets found by Kepler; 2. Prove planetary nature of Kepler-detected rocky exoplanets For objective #1, will observe secondary eclipse* depths for ~20 planetary systems – cooler Jupiters, hot Neptunes, and the hottest SuperEarths – to determine temperatures and constrain albedos. –Observations will also constrain or determine orbital eccentricities, allowing assessment of tidal dissipation and other dynamical effects For objective #2, will follow up ~40 Kepler candidates with shallow transits* that could be caused by SuperEarths, including some in habitable zone. Will measure transit depths to see if they are the same in visible and IR in order to eliminate false positives. –Results will be improved statistics on the frequency of rocky planets around sun-like stars [*transit = planet in front of star; secondary eclipse = planet behind star]

Spitzer Space Telescope Mww-6 How Warm Spitzer Addresses Astrobiology Goal, cont. Goal #1 is addressed indirectly by three programs: –Dynamic Studies of Exoplanet Atmospheres PI H.Knutson, Harvard (1138 hours) Will observe secondary eclipses for all accessible transiting planets and determine phase curves for five of the most interesting objects. Focus is on Hot Jupiters –The Spitzer Exoplanetary Atmosphere Survey PI J.Harrington, Central Florida (200 hours) Target of Opportunity program to measure eclipses and transits of newly discovered transiting planets These programs are aimed at studying the atmospheres and interiors of Hot Jupiters but seem likely to yield insights relevant to terrestrial planets

Spitzer Space Telescope Mww-7 How Warm Spitzer Addresses Astrobiology Goals, cont. Goal #1 (continued) –Young Stellar Object Variability PI J Stauffer, IPAC (550 hours) Comprehensive study of YSO variability which should yield information about disk structure and evolution and thus inform studies of terrestrial planets; e.g. by identifying structures in the inner disks of YSOs possibly caused by forming/migrating exoplanets Goals #4 and #6 – (Evolution and future of life) – are indirectly addressed by one program: –The Warm Spitzer NEO Survey PI D.Trilling, Northern Arizona (500 hours) Size determinations for about 500 Near Earth Objects, including some as small as ~100m. Will provide insights into possible role of NEOs, including extinct cometary nuclei, into bringing organics to Earth, as well as key information relevant to hazard assessment.

Spitzer Space Telescope Mww-8 Conclusions Selected Warm Spitzer Exploration programs will make major contributions – both direct and by setting a framework for further studies - towards meeting Astrobiology goals, by: –Providing data on properties of SuperEarths –Identifying SuperEarths for detailed study by JWST –Supporting determination of eta-sub-Earth by eliminating false positives from Kepler data base –Contributing greatly to our general understanding of exoplanetary systems –Characterizing aspects of YSO variability which may relate to terrestrial planet formation and frequency –Supporting assessment of potential role of NEOs as facilitators of or threats to terrestrial life GO Programs to be selected in 2010 and 2011 may provide additional contributions to Astrobiology As of now these activities will continue through mid-2011 –Extension beyond then, ideally through end of 2013, will depend on actual results from Warm Spitzer, and on evaluation of Warm Spitzer in 2010 Senior Review.