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Published June 20, 2013 | Submitted + Published
Journal Article Open

Warm Spitzer Photometry of Three Hot Jupiters: HAT-P-3b, HAT-P-4b and HAT-P-12b


We present Warm Spitzer/IRAC secondary eclipse time series photometry of three short-period transiting exoplanets, HAT-P-3b, HAT-P-4b and HAT-P-12b, in both the available 3.6 and 4.5 μm bands. HAT-P-3b and HAT-P-4b are Jupiter-mass objects orbiting an early K and an early G dwarf star, respectively. For HAT-P-3b we find eclipse depths of 0.112^(+0.015)_(-0.030) (3.6 μm) and 0.094^(+0.016)_(-0.009)(4.5 μm). The HAT-P-4b values are 0.142^(+0.014)_(-0.016)(3.6 μm) and 0.122^(+0.012)_(-0.014)(4.5 μm). The two planets' photometry is consistent with inefficient heat redistribution from their day to night sides (and low albedos), but it is inconclusive about possible temperature inversions in their atmospheres. HAT-P-12b is a Saturn-mass planet and is one of the coolest planets ever observed during secondary eclipse, along with the hot Neptune GJ 436b and the hot Saturn WASP-29b. We are able to place 3σ upper limits on the secondary eclipse depth of HAT-P-12b in both wavelengths: <0.042% (3.6 μm) and <0.085% (4.5 μm). We discuss these results in the context of the Spitzer secondary eclipse measurements of GJ 436b and WASP-29b. It is possible that we do not detect the eclipses of HAT-P-12b due to high eccentricity, but find that weak planetary emission in these wavelengths is a more likely explanation. We place 3σ upper limits on the |e cos ω| quantity (where e is eccentricity and ω is the argument of periapsis) for HAT-P-3b (<0.0081) and HAT-P-4b (<0.0042), based on the secondary eclipse timings.

Additional Information

© 2013 American Astronomical Society. Received 2013 March 11; accepted 2013 April 30; published 2013 May 30. We thank Jonathan Fraine for helpful discussions on "prayer bead" uncertainty estimation. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. The Center for Exoplanets and Habitable Worlds is supported by the Pennsylvania State University, the Eberly College of Science, and the Pennsylvania Space Grant Consortium. We thank the anonymous referee for a careful review of this paper.

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Published - 0004-637X_770_2_102.pdf

Submitted - 1305.0833v1.pdf


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