CSI papers published: Statistical characterization of hot Jupiter atmospheres

Statistical characterization of hot Jupiter atmospheres using Spitzer's secondary eclipses by E. Garhart, CSI member Nikole Lewis, and colleagues; email: nikole.lewis@cornell.edu

We report 78 secondary eclipse depths for a sample of 36 transiting hot Jupiters observed at 3.6- and 4.5 microns using the Spitzer Space Telescope. Our eclipse results for 27 of these planets are new, and include highly irradiated worlds such as KELT-7b, WASP-87b, WASP-76b, and WASP-64b, and important targets for JWST such as WASP-62b. We find that WASP-62b has a slightly eccentric orbit e cos(omega) = 0.00614 +/- 0.00058, and we confirm the eccentricity of HAT-P-13b and WASP-14b. The remainder are individually consistent with circular orbits, but we find statistical evidence for eccentricity increasing with orbital period in our range from 1 to 5 days. Our day-side brightness temperatures for the planets yield information on albedo and heat redistribution, following Cowan and Agol (2011). Planets having maximum day side temperatures exceeding ~ 2200K are consistent with zero albedo and distribution of stellar irradiance uniformly over the day-side hemisphere. Our most intriguing result is that we detect a systematic difference between the emergent spectra of these hot Jupiters as compared to blackbodies. The ratio of observed brightness temperatures, Tb(4.5)/Tb(3.6), increases with equilibrium temperature by 98 +/- 26 parts-per-million per Kelvin, over the entire temperature range in our sample (800K to 2500K). No existing model predicts this trend over such a large range of temperature. We suggest that this may be due to a structural difference in the atmospheric temperature profile between the real planetary atmospheres as compared to models.

Nikole Lewis, Astronomy & Planetary Science

Klarman Hall at sunset

Tweets from CSInst

is an annual twitter competition hosted by to determine the most popular exoplanet of the year.… https://t.co/IgYMfPedoH
1 day 16 hours ago
We endorse , the 1st close-in planet found around a white dwarf, for ! To learn more about the… https://t.co/tX63gdObmU
1 day 17 hours ago
RT : So proud to hear the 100th episode of ! Thank you for bringing our to the local… https://t.co/naRcsnpdSB
2 days 13 hours ago
RT : Learn skills ! is offered online & open to everyone! Build a comm strategy,create… https://t.co/2vOy0egObM
2 days 15 hours ago
RT : Is there beyond ? "I think the numbers are forever in our favor," says of &… https://t.co/5VOEFUwRav
3 days 21 hours ago
Happy Thanksgiving to our American colleagues & followers. This year’s parade in NYC included a https://t.co/AMzaF6lKIo
3 days 22 hours ago