Paper: astro-ph/0507618
Date: Tue, 26 Jul 2005 19:32:11 GMT (52kb)

Title: High-precision K-band photometry of the secondary eclipse of HD209458

Authors: Ignas Snellen (leiden)
Comments: 6 pages; accepted by MNRAS
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Recently, mid-infrared Spitzer observations have been presented that show the
light decrement due to the passage of a planet behind its host star. These
measurements of HD209458b and TrES-1 are the first detections of direct light
from an extra-solar planet. Interpretation of these results in terms of planet
equipartition temperature and bond albedo is however strongly model dependent
and require additional observations at shorter wavelengths. Here we report on
two attempts to detect the secondary eclipse of HD209458b from the ground in
K-band, using the UK InfraRed Telescope (UKIRT). A photometry precision of
0.12% relative to two nearby reference stars was reached during both occasions,
but no firm detection of the eclipses were obtained. The first observation
shows a flux decrement of -0.13+-0.18%, and the second of -0.10+-0.10%. A
detailed description of the observing strategy, data reduction and analysis is
given, and a discussion on how the precision in ground-based K-band photometry
could be further improved. In addition we show that the relative photometry
between the target and the reference stars between the two epochs is consistent
down to the <0.1% level, which is interesting in the light of possible
near-infrared surveys to search for transiting planets around M and L dwarfs.

\\ ( http://arXiv.org/abs/astro-ph/0507618 , 52kb)