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| Paper: |
The WFCAM Transit Survey: A Search for Rocky Planets Around
Cool Stars |
| Volume: |
448, 16th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun |
| Page: |
803 |
| Authors: |
Birkby, J.; Hodgkin, S.; Pinfield, D.; WTS consortium |
| Abstract: |
We report on the WFCAM Transit Survey which is a near-infrared
photometric monitoring campaign designed primarily to test the
predictions of planet formation theory. We monitor a statisically
significant sample of ∼6,000 M-dwarfs (M<0.6M☉)
across 6 sq. deg of the sky, by taking advantage of the
highly-efficient queue-scheduled operational mode of the 3.8m United
Kingdom Infrared Telescope. Our light curves have RMS < 1% between
13 < J < 16 magnitudes and preliminary simulations indicate the survey
is sensitive to at least Jupiter-like transits of M-dwarfs. The
survey is approximately 25% complete and within this dataset we
find i) no planet-like transit events, despite thorough and
extensive follow-up this summer and ii) 32 new M-dwarf eclipsing
binaries. We do not speculate on the planet fraction of M-dwarfs at
this incomplete stage of our survey, but once we achieve 1,000
epochs of observation on our entire M-dwarf sample, we will have a
significant observational constraint to place on occurrence of
planets around M-dwarfs. We report masses and radii for three of our
newly discovered eclipsing binary, with errors of 3–7%, which all
show inflated radii when compared to stellar evolution models
(e.g. Baraffe et al. (1998)). Our results support the growing body of
observations with inflated M-dwarf radii, which may be caused by
increased magnetic activity inhibiting the convection efficiency or
increased star spot coverage (e.g. Chabrier et al. (2007); Jackson et al. (2009)). Finally, we
present preliminary mass and radius estimates of a fourth new
eclipsing binary, which is one of the lowest mass binary systems
ever discovered and will provide a calibrating point in the desert
of observations between 0.1–0.2M☉. |
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