WARM SPITZER PHOTOMETRY OF THE TRANSITING EXOPLANETS CoRoT-1 AND CoRoT-2 AT SECONDARY ECLIPSE
- Planetary Systems Laboratory, NASA's Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
- Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States)
- Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States)
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 05844 (United States)
- Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States)
- Department of Physics, Principia College, Elsah, IL 62028 (United States)
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)
We measure secondary eclipses of the hot giant exoplanets CoRoT-1 at 3.6 and 4.5 {mu}m, and CoRoT-2 at 3.6 {mu}m, both using Warm Spitzer. We find that the Warm Spitzer mission is working very well for exoplanet science. For consistency of our analysis we also re-analyze archival cryogenic Spitzer data for secondary eclipses of CoRoT-2 at 4.5 and 8 {mu}m. We compare the total data for both planets, including optical eclipse measurements by the CoRoT mission, and ground-based eclipse measurements at 2 {mu}m, to existing models. Both planets exhibit stronger eclipses at 4.5 than at 3.6 {mu}m, which is often indicative of an atmospheric temperature inversion. The spectrum of CoRoT-1 is best reproduced by a 2460 K blackbody, due either to a high altitude layer that strongly absorbs stellar irradiance, or an isothermal region in the planetary atmosphere. The spectrum of CoRoT-2 is unusual because the 8 {mu}m contrast is anomalously low. Non-inverted atmospheres could potentially produce the CoRoT-2 spectrum if the planet exhibits line emission from CO at 4.5 {mu}m, caused by tidal-induced mass loss. However, the viability of that hypothesis is questionable because the emitting region cannot be more than about 30% larger than the planet's transit radius, based on the ingress and egress times at eclipse. An alternative possibility to account for the spectrum of CoRoT-2 is an additional opacity source that acts strongly at wavelengths less than 5 {mu}m, heating the upper atmosphere while allowing the deeper atmosphere seen at 8 {mu}m to remain cooler. We obtain a similar result as Gillon et al. for the phase of the secondary eclipse of CoRoT-2, implying an eccentric orbit with e cos({omega}) = -0.0030 {+-} 0.0004.
- OSTI ID:
- 21567652
- Journal Information:
- Astrophysical Journal, Vol. 726, Issue 2; Other Information: DOI: 10.1088/0004-637X/726/2/95; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
WARM SPITZER PHOTOMETRY OF THREE HOT JUPITERS: HAT-P-3b, HAT-P-4b AND HAT-P-12b
SPITZER INFRARED OBSERVATIONS AND INDEPENDENT VALIDATION OF THE TRANSITING SUPER-EARTH CoRoT-7 b