NEAR-INFRARED THERMAL EMISSION FROM WASP-12b: DETECTIONS OF THE SECONDARY ECLIPSE IN Ks, H, AND J
- Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)
- Departement de physique, Universite de Montreal, C.P. 6128 Succ. Centre-Ville, Montreal, QC, H3C 3J7 (Canada)
- Canada-France-Hawaii Telescope Corporation, 65-1238 Mamalahoa Highway, Kamuela, HI 96743 (United States)
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA, 95064 (United States)
- Canadian Institute for Theoretical Astrophysics, 60 St. George Street, University of Toronto, Toronto ON M5S 3H8 (Canada)
We present Ks, H, and J-band photometry of the very highly irradiated hot Jupiter WASP-12b using the Wide-field Infrared Camera on the Canada-France-Hawaii telescope. Our photometry brackets the secondary eclipse of WASP-12b in the Ks and H bands, and in J band starts in mid-eclipse and continues until well after the end of the eclipse. We detect its thermal emission in all three near-infrared bands. Our secondary eclipse depths are 0.309{sup +0.013}{sub -0.012}% in Ks band (24{sigma}), 0.176{sup +0.016}{sub -0.021}% in H band (9{sigma}), and 0.131{sup +0.027}{sub -0.029}% in J band (4{sigma}). All three secondary eclipses are best fit with a consistent phase, {phi}, that is compatible with a circular orbit: {phi} = 0.4998{sup +0.0008}{sub -0.0007}. The limits on the eccentricity, e, and argument of periastron, {omega}, of this planet from our photometry alone are thus |ecos {omega}| < 0.0040. By combining our secondary eclipse times with others published in the literature, as well as the radial-velocity and transit-timing data for this system, we show that there is no evidence that WASP-12b is precessing at a detectable rate and that its orbital eccentricity is likely zero. Our thermal-emission measurements also allow us to constrain the characteristics of the planet's atmosphere; our Ks-band eclipse depth argues strongly in favor of inefficient day to nightside redistribution of heat and a low Bond albedo for this very highly irradiated hot Jupiter. The J- and H-band brightness temperatures are slightly cooler than the Ks-band brightness temperature, and thus hint at the possibility of a modest temperature inversion deep in the atmosphere of WASP-12b; the high-pressure, deep atmospheric layers probed by our J- and H-band observations are likely more homogenized than the higher altitude layer probed by our Ks-band observations. Lastly, our best-fit Ks-band eclipse has a marginally longer duration than would otherwise be expected; this may be tentative evidence for material being tidally stripped from the planet-as was predicted for this system by Li and collaborators, and for which observational confirmation was recently arguably provided by Fossati and collaborators.
- OSTI ID:
- 21583262
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 141, Issue 2; Other Information: DOI: 10.1088/0004-6256/141/2/30; ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
Similar Records
GROUND-BASED DETECTIONS OF THERMAL EMISSION FROM CoRoT-1b AND WASP-12b
DAY-SIDE z'-BAND EMISSION AND ECCENTRICITY OF WASP-12b