Paper: astro-ph/0601128
Date: Fri, 6 Jan 2006 16:18:10 GMT (150kb)

Title: Eclipsing binaries in extrasolar planet transit surveys: the case of
SuperWASP

Authors: B. Willems, U. Kolb, and S. Justham

Comments: Accepted for publication in MNRAS
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Using a comprehensive binary population synthesis scheme, we investigate the
statistical properties of a sample of eclipsing binaries that is detectable by
an idealised extrasolar planet transit survey with specifications broadly
similar to those of the SuperWASP (Wide Angle Search for Planets) project. In
this idealised survey the total number of detectable single stars in the
Galactic disc is of the order of 10^6-10^7, while, for a flat initial mass
ratio distribution, the total number of detectable eclipsing binaries is of the
order of 10^4-10^5. The majority of the population of detectable single stars
is made up of main-sequence stars (60%), horizontal-branch stars (20%), and
giant-branch stars (10%). The largest contributions to the population of
detectable eclipsing binaries stem from detached double main-sequence star
binaries (60%), detached giant-branch main-sequence star binaries (20%), and
detached horizontal-branch main-sequence star binaries (10%). The ratio of the
number of eclipsing binaries to the number of single stars detectable by the
idealised SuperWASP survey varies by less than a factor of 2.5 across the sky,
and decreases with increasing Galactic latitude. It is found to be largest in
the direction of the Galactic longitude l=-7.5deg and the Galactic latitude
b=-22.5deg. We also show that the fractions of systems in different subgroups
of eclipsing binaries are sensitive to the adopted initial mass ratio
distribution, which is one of the poorest constrained input parameters in
present-day binary population synthesis calculations. This suggests that once
statistically meaningful results from transit surveys are available, they will
be able to significantly improve the predictive power of population synthesis
studies of interacting binaries and related objects. (abridged)

\\ ( http://arXiv.org/abs/astro-ph/0601128 , 150kb)