From: LARRY KLAES (ljk4_at_msn.com)
Date: Fri Oct 19 2007 - 08:34:47 PDT
arXiv:0710.3461
Date: Thu, 18 Oct 2007 09:00:31 GMT (1255kb)
Title: The Frequency of Large Radius Hot and Very Hot Jupiters in omega
Centauri
Authors: David T F Weldrake (1), Penny D Sackett (2) and Terry J Bridges
(3).
((1) MPIA, Heidelberg, (2) RSAA, Mount Stromlo Observatory, (3) Queen's
University)
Categories: astro-ph
Comments: 22 pages, 8 figures, accepted for publication in ApJ
\\
We present the results of a deep, wide-field search for transiting `Hot
Jupiter (HJ)' planets in the globular cluster omega Centauri. As a result of
a
25-night observing run with the ANU 40-inch telescope at Siding Spring
Observatory, a total of 109,726 stellar time series composed of 787
independent
data points were produced with differential photometry in a 52x52' (0.75
deg^2)
field centered on the cluster core, but extending well beyond. Taking into
account the size of transit signals as a function of stellar radius, 45,406
stars have suitable photometric accuracy (<=0.045 mag to V=19.5) to search
for
transits. Of this sample, 31,000 stars are expected to be main sequence
cluster
members. All stars, both cluster and foreground, were subjected to a
rigorous
search for transit signatures; none were found. Extensive Monte Carlo
simulations based on our actual data set allows us to determine the
sensitivity
of our survey to planets with radii ~1.5R_Jup, and thus place statistical
upper
limits on their occurrence frequency 'F'. Smaller planets are undetectable
in
our data. At 95% confidence, the frequency of Very Hot Jupiters (VHJs) with
periods P satisfying 1d<P<3d can be no more than F_VHJ < 1/1040 in omega
Cen.
For HJ and VHJ distributed uniformly over the orbital period range 1d<P<5d,
F_VHJ+HJ < 1/600. Our limits on large, short-period planets are comparable
to
those recently reported for other Galactic fields, despite being derived
with
less telescope time.
\\ ( http://arxiv.org/abs/0710.3461 , 1255kb)
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