MOST, Microvariablity and Oscillations of STars satellite |
MOST, Microvariablity and Oscillations of STars satellite |
Mar 17 2006, 04:07 PM
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
Astrophysics, abstract
astro-ph/0603410 From: Jason F. Rowe [view email] Date: Thu, 16 Mar 2006 00:33:52 GMT (159kb) An Upper Limit on the Albedo of HD 209458b: Direct Imaging Photometry with the MOST Satellite Authors: J.F. Rowe, J.M. Matthews, S. Seager, R. Kuschnig, D.B. Guenther, A.F.J. Moffat, S.M. Rucinski, D. Sasselov, G.A.H. Walker, W.W. Weiss Comments: 29 pages, 9 figures. Accepted for publication in the Astrophysical Journal (July 2006, v645n1) We present space-based photometry of the transiting exoplanetary system HD 209458 obtained with the MOST (Microvariablity and Oscillations of STars) satellite, spanning 14 days and covering 4 transits and 4 secondary eclipses. The HD 209458 photometry was obtained in MOST's lower-precision Direct Imaging mode, which is used for targets in the brightness range $6.5 < V < 13$. We describe the photometric reduction techniques for this mode of observing, in particular the corrections for stray Earthshine. We do not detect the secondary eclipse in the MOST data, to a limit in depth of 0.053 mmag (1 \sigma). We set a 1 \sigma upper limit on the planet-star flux ratio of 4.88 x 10^-5 corresponding to a geometric albedo upper limit in the MOST bandpass (400 to 700 nm) of 0.25. The corresponding numbers at the 3 \sigma level are 1.34 x 10^-4 and 0.68 respectively. HD 209458b is half as bright as Jupiter in the MOST bandpass. This low geometric albedo value is an important constraint for theoretical models of the HD209458b atmosphere, in particular ruling out the presence of reflective clouds. A second MOST campaign on HD 209458 is expected to be sensitive to an exoplanet albedo as low as 0.13 (1 sigma), if the star does not become more intrinsically variable in the meantime. http://arxiv.org/abs/astro-ph/0603410 -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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Mar 25 2006, 05:35 PM
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Member Group: Members Posts: 124 Joined: 23-March 06 Member No.: 723 |
thanks for that update on MOST
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