Finding Habitable Transiting SuperEarth Exoplanets, and Characterizing their Atmospheres Using the James Webb Space Telescope
Drake Deming (Goddard)
Monday 21st September 2009, 12:00pm
Pratt conference room, 60 Garden Street
Doppler and transit surveys are finding extrasolar planets of ever smaller mass and radius, and are now sampling the domain of superEarths. An all-sky transit survey (e.g., TESS) targeted to the brightest
stars would find the most favorable cases for photometric and spectroscopic characterization using the James Webb Space Telescope (JWST). We couple the simulated yield of TESS to a sensitivity model for
the MIRI and NIRSpec instruments on JWST, focusing on the TESS planets with radii between Earth and
Neptune. These simulations consider secondary eclipse filter photometry using JWST/MIRI, comparing the 11- and 15 micron bands to measure CO2 absorption in superEarths, as well as JWST/NIRSpec spectroscopy of water absorption from 1.7- to 3.0 microns, and CO2 absorption at 4.3 microns. The results show that JWST will be capable of characterizing dozens of TESS superEarths with temperatures above the habitable range, using both MIRI and NIRspec. TESS should discover about eight nearby habitable transiting superEarths, all orbiting lower main sequence stars. The principal sources of uncertainty in the prospects for JWST characterization of habitable superEarths are superEarth frequency and the nature of superEarth atmospheres. Based on our estimating these uncertainties, JWST should be able to measure the temperature, and identify molecular absorptions (water, CO2) in 1 to 4 nearby habitable TESS superEarths orbiting lower main sequence stars.