On the Selection of Photometric Planetary Transits

Astrophysics, abstract
astro-ph/0301295

From: Andrew Drake <ajd@astro.princeton.edu>

Date: Wed, 15 Jan 2003 16:07:17 GMT   (49kb)

Authors:
A.J. Drake

Comments: 11 pages, 2 figures, 1 table, submitted to ApJ

In this paper we present a new method for removing the stellar transits from
planetary transit candidate lists based on the presence of gravity darkening in
their light curves. This method will greatly reduce the number of transit
candidates from future surveys requiring spectroscopic follow up with large
telescopes. We show that the presence of this effect can be used to detect
stellar secondaries with masses ~0.2 M_sun orbiting sun-like stars at a
photometric accuracy level which has already been achieved in transit surveys.
Unlike the usual candidate selection method, which are primarily based on the
estimated radius of the orbiting object, this technique is not biased against
bona-fide planets and brown dwarfs with large radii because the amplitude of
the effect depends on the transiting object’s mass. We show that many of the
recent OGLE-III planetary candidates exhibit the presence of a significant
gravity effect and are therefore likely to be due to a stellar secondary. The
full transit light curves of white dwarfs will generally not mimic transits of
small planets because of the significant gravity darkening effect. We discuss
the relative merits of methods used to detect transit candidates which are due
to stellar blends rather than planets. We outline how photometric observations
taken in two bands can be used to detect the presence of stellar blends.

References and citations for this submission:

SLAC-SPIRES HEP (refers to ,
cited by, arXiv reformatted)