DETECTION OF K-S-BAND THERMAL EMISSION FROM WASP-3b

作者：Zhao Ming^*; Milburn Jennifer; Barman Travis; Hinkley Sasha; Swain Mark R; Wright Jason; Monnier John D

来源：Astrophysical Journal Letters, 2012, 748(1): L8.

DOI：10.1088/2041-8205/748/1/L8

• infrared: planetary systems
• planetary systems
• stars: individual (WASP-3)

We report the detection of thermal emission from the hot Jupiter WASP-3b in the K-S band, using a newly developed guiding scheme for the WIRC instrument at the Palomar Hale 200 inch telescope. Our new guiding scheme has improved the telescope guiding precision by a factor of similar to 5-7, significantly reducing the correlated systematics in the measured light curves. This results in the detection of a secondary eclipse with depth of 0.181% +/- 0.020% (9 sigma)-a significant improvement in WIRC's photometric precision and a demonstration of the capability of Palomar/WIRC to produce high-quality measurements of exoplanetary atmospheres. Our measured eclipse depth cannot be explained by model atmospheres with heat redistribution but favors a pure radiative equilibrium case with no redistribution across the surface of the planet. Our measurement also gives an eclipse phase center of 0.5045 +/- 0.0020, corresponding to an e cos. of 0.0070 +/- 0.0032. This result is consistent with a circular orbit, although it also suggests that the planet's orbit might be slightly eccentric. The possible non-zero eccentricity provides insight into the tidal circularization process of the star-planet system, but might also have been caused by a second low-mass planet in the system, as suggested by a previous transit timing variation study. More secondary eclipse observations, especially at multiple wavelengths, are necessary to determine the temperature-pressure profile of the planet's atmosphere and shed light on its orbital eccentricity.

• 出版日期2012-3-20