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We report the results of a globally coordinated photometric campaign to search for transits by the P ~ 30 d and P ~ 60 d 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 (P ~ 30 d) do not currently occur, in concordance with the best-fit i = 50 degree co-planar configuration obtained by dynamical fits to the most recent radial velocity data for the system. Transits by planet b (P ~ 60 d) 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.
We have performed simulations to investigate the dynamics of the M dwarf star GJ 876 in an attempt to reveal any stabilizing mechanism for sustaining the system.We simulated different coplanar and noncoplanar configurations of two-planet systems and
Some of the most scientifically valuable transiting planets are those that were already known from radial velocity (RV) surveys. This is primarily because their orbits are well characterized and they preferentially orbit bright stars that are the tar
We report the discovery of two planetary systems, namely G 264-012, an M4.0 dwarf with two terrestrial planets ($M_{rm b}sin{i} = 2.50^{+0.29}_{-0.30}$ M$_{oplus}$ and $M_{rm c}sin{i} = 3.75^{+0.48}_{-0.47}$ M$_{oplus}$), and Gl 393, a bright M2.0 dw
Short-period super-Earths and Neptunes are now known to be very frequent around solar-type stars. Improving our understanding of these mysterious planets requires the detection of a significant sample of objects suitable for detailed characterization
Planets are known to orbit giant stars, yet there is a shortage of planets orbiting within ~0.5 AU (P<100 days). First-ascent giants have not expanded enough to engulf such planets, but tidal forces can bring planets to the surface of the star far be