Title

SPITZER IRAC SECONDARY ECLIPSE PHOTOMETRY OF THE TRANSITING EXTRASOLAR PLANET HAT-P-1b

Authors

Authors

K. Todorov; D. Deming; J. Harrington; K. B. Stevenson; W. C. Bowman; S. Nymeyer; J. J. Fortney;G. A. Bakos

Comments

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Abbreviated Journal Title

Astrophys. J.

Keywords

eclipses; planetary systems; techniques: photometric; INFRARED-EMISSION SPECTRUM; EXOPLANET HD 189733B; THERMAL EMISSION; TEMPERATURE INVERSION; HOT JUPITERS; GIANT PLANETS; LIGHT CURVES; ATMOSPHERES; 209458B; SEARCH; Astronomy & Astrophysics

Abstract

We report Spitzer/IRAC photometry of the transiting giant exoplanet HAT-P-1b during its secondary eclipse. This planet lies near the postulated boundary between the pM and pL-class of hot Jupiters, and is important as a test of models for temperature inversions in hot Jupiter atmospheres. We derive eclipse depths for HAT-P-1b, in units of the stellar flux, that are: 0.080%+/- 0.008% [3.6 mu m], 0.135%+/- 0.022% [4.5 mu m], 0.203%+/- 0.031% [5.8 mu m], and 0.238%+/- 0.040% [8.0 mu m]. These values are best fit using an atmosphere with a modest temperature inversion, intermediate between the archetype inverted atmosphere (HD 209458b) and a model without an inversion. The observations also suggest that this planet is radiating a large fraction of the available stellar irradiance on its dayside, with little available for redistribution by circulation. This planet has sometimes been speculated to be inflated by tidal dissipation, based on its large radius in discovery observations, and on a non-zero orbital eccentricity allowed by the radial velocity data. The timing of the secondary eclipse is very sensitive to orbital eccentricity, and we find that the central phase of the eclipse is 0.4999 +/- 0.0005. The difference between the expected and observed phase indicates that the orbit is close to circular, with a 3 sigma limit of vertical bar e cos omega vertical bar < 0.002.

Journal Title

Astrophysical Journal

Volume

708

Issue/Number

1

Publication Date

1-1-2010

Document Type

Article

Language

English

First Page

498

Last Page

504

WOS Identifier

WOS:000272790400047

ISSN

0004-637X

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