Paper: astro-ph/0601092
Date: Wed, 4 Jan 2006 23:56:24 GMT (66kb)

Title: Resolving the Surfaces of Extrasolar Planets With Secondary Eclipse
Light Curves

Authors: Peter K. G. Williams, David Charbonneau, Curtis S. Cooper, Adam P.
Showman, Jonathan J. Fortney

Comments: AASTeX 5.2, 22 pages, 5 figures, submitted to ApJ
\\
We present a method that employs the secondary eclipse light curves of
transiting extrasolar planets to probe the spatial variation of their thermal
emission. This technique permits an observer to resolve the surface of the
planet without needing to isolate its light from that of the central star. We
evaluate the feasibility of this technique for the HD 209458 system by first
modeling the secondary eclipse light curves that would result from several
representations of the planetary emission and then simulating the noise
properties of observations of this signal with the Spitzer Space Telescope
Infrared Array Camera (IRAC). We consider two representations of the planetary
thermal emission: a simple parameterized model, and the results of a dynamical
simulation of the planetary atmosphere previously published by Cooper &
Showman. We find that observations of the secondary eclipse light curve are
most sensitive to the longitudinal contrast in the emission of the planetary
hemisphere visible near opposition. We quantify this signal with a parameter,
the "uniform time offset," which measures the time delay between the observed
secondary eclipse and that of a simulated, uniformly-emitting planet. We
compare the predicted amplitude of this parameter for HD 209458b with the
precision with which IRAC could measure it. We find that IRAC observations at
3.6 um of a single secondary eclipse should permit sufficient precision to test
the Cooper & Showman model of the planetary atmosphere. We quantify the
signal-to-noise ratio for this offset in the remaining IRAC bands and find that
a modest improvement in photometric precision should permit similarly robust
detections.

\\ ( http://arXiv.org/abs/astro-ph/0601092 , 66kb)