2010ApJ...723.1436C -
Astrophys. J., 723, 1436-1446 (2010/November-2)
A new 24 µm phase curve for υ Andromedae b.
CROSSFIELD I.J.M., HANSEN B.M.S., HARRINGTON J., CHO J.Y.-K., DEMING D., MENOU K. and SEAGER S.
Abstract (from CDS):
We report the detection of 24 µm variations from the planet-hosting υ Andromedae system consistent with the orbital periodicity of the system's innermost planet, υ And b. We find a peak-to-valley phase curve amplitude of 0.00130 times the mean system flux. Using a simple model with two hemispheres of constant surface brightness and assuming a planetary radius of 1.3 RJ give a planetary temperature contrast of ≳900 K and an orbital inclination of ≳28°. We further report the largest phase offset yet observed for an extrasolar planet: the flux maximum occurs ∼80° before phase 0.5. Such a large phase offset is difficult to reconcile with most current atmospheric circulation models. We improve on earlier observations of this system in several important ways: (1) observations of a flux calibrator star demonstrate the MIPS detector is stable to 10–4 on long timescales, (2) we note that the background light varies systematically due to spacecraft operations, precluding use of this background as a flux calibrator (stellar flux measured above the background is not similarly affected), and (3) we calibrate for flux variability correlated with motion of the star on the MIPS detector. A reanalysis of our earlier observations of this system is consistent with our new result.
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Journal keyword(s):
infrared: planetary systems - planetary systems - planets and satellites: individual: υ And b - stars: individual: υ And b - techniques: photometric
Simbad objects:
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