MOA-2009-BLG-387Lb: a massive planet orbiting an M dwarf

By V. Batista, A. Gould, S. Dieters, S. Dong, I. Bond, J. Beaulieu, D. Maoz, B. Monard, G. Christie, J. Mccormick and 18 more. 2011

146 citations recorded by the source corpus.

Aims. We report the discovery of a planet with a high planet-to-star mass ratio in the microlensing event MOA-2009-BLG-387, which exhibited pronounced deviations over a 12-day interval, one of the longest for any planetary event. The host is an M dwarf, with a mass in the range 0.07 M_⊙ < M_(host) < 0.49 M_⊙ at 90% confidence. The planet-star mass ratio q = 0.0132 ± 0.003 has been measured extremely well, so at the best-estimated host mass, the planet mass is m_p = 2.6 Jupiter masses for the median host mass, M = 0.19 M_⊙. Methods. The host mass is determined from two “higher order” microlensing parameters. One of these, the angular Einstein radius θ_E = 0.31 ± 0.03 mas has been accurately measured, but the other (the microlens parallax πE, which is due to the Earth’s orbital motion) is highly degenerate with the orbital motion of the planet. We statistically resolve the degeneracy between Earth and planet orbital effects by imposing priors from a Galactic model that specifies the positions and velocities of lenses and sources and a Kepler model of orbits. Results. The 90% confidence intervals for the distance, semi-major axis, and period of the planet are 3.5 kpc < D_L < 7.9 kpc, 1.1 AU < a < 2.7 AU, and 3.8 yr < P < 7.6 yr, respectively.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/92f7b71f126b686af11329ff637a0c325576046d

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In Astronomy and Astrophysics

Citations in the corpus

Microlensing Surveys for Exoplanets (2012, background): “…can be accommodated by multiplying the local probability density of the canonical parameters by the Jacobian of the transformation between the canonical and physical parameters, weighted by the appropriate priors on the physical parameters (Dominik 2006, Batista et al. 2011, Skowron et al. 2011).”