Title

A Spitzer infrared radius for the transiting extrasolar planet hd 209458b

Authors

Authors

L. J. Richardson; J. Harrington; S. Seager;D. Deming

Comments

Authors: contact us about adding a copy of your work at STARS@ucf.edu

Abbreviated Journal Title

Astrophys. J.

Keywords

eclipses; infrared : general; stars : individual (HD 209458); PARAMETERS; ATMOSPHERE; HD-209458; SEARCH; TIDES; STAR; Astronomy & Astrophysics

Abstract

We have measured the infrared transit of the extrasolar planet HD 209458b using the Spitzer Space Telescope. We observed two primary eclipse events ( one partial and one complete transit) using the 24 mu m array of the Multiband Imaging Photometer for Spitzer (MIPS). We analyzed a total of 2392 individual images (10 s integrations) of the planetary system, recorded before, during, and after transit. We performed optimal photometry on the images and used the local zodiacal light as a short-term flux reference. At this long wavelength, the transit curve has a simple boxlike shape, allowing robust solutions for the stellar and planetary radii independent of stellar limb darkening, which is negligible at 24 mu m. We derive a stellar radius of R-* (1.06 +/- 0.07) R-circle dot, a planetary radius of R-p = (1.26 +/- 0.08)R-J, and a stellarmass of 1.17M(circle dot). Within the errors, our results agree with themeasurements at visible wavelengths. The 24 mu m radius of the planet therefore does not differ significantly compared to the visible result. We point out the potential for deriving extrasolar transiting planet radii to high accuracy using transit photometry at slightly shorter IR wavelengths where greater photometric precision is possible.

Journal Title

Astrophysical Journal

Volume

649

Issue/Number

2

Publication Date

1-1-2006

Document Type

Article

Language

English

First Page

1043

Last Page

1047

WOS Identifier

WOS:000240854200043

ISSN

0004-637X

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