On the Search for Transits of the Planets Orbiting GL 876 [PREPRINT]
JAMES COOK UNIV OF NORTH QUEENSLAND TOWNSVILLE (AUSTRALIA)
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We report the results of a globally coordinated photometric campaign to search for transits by the P30d and P60d outer planets of the 3-planet system orbiting the nearby M-dwarf Gl 876. These two planets experience strong mutual perturbations, which necessitate use of a dynamical four-body model to compute transit ephemerides for the system. Our photometric data have been collected from published archival sources, as well as from our photometric campaigns that were targeted to specific transit predictions. Our analysis indicates that transits by planet c P30d do not currently occur, in concordance with the best-fit i 50 deg. co-planar configuration obtained by dynamical fits to the most recent radial velocity data for the system. Transits by planet b P60d are not entirely ruled out by our observations, but our data indicate that it is very unlikely that they occur. Our experience with the Gl 876 system suggests that a distributed ground-based network of small telescopes can be used to search for transits of very low mass M-stars by terrestrial-sized planets.
- Celestial Mechanics