Updated OGLE-2005-071L b data

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Updated OGLE-2005-071L b data

Post by Sirius_Alpha on 10th April 2008, 6:30 pm

OGLE-2005-BLG-071Lb, the Most Massive M-Dwarf Planetary Companion?

http://arxiv.org/abs/0804.1354

abstract wrote:We combine all available information to constrain the nature of OGLE-2005-BLG-071Lb, the second planet discovered by microlensing and the first in a high-magnification event. These include photometric and astrometric measurements from Hubble Space Telescope, as well as constraints from higher-order effects extracted from the ground-based light curve, such as microlens parallax, planetary orbital motion and finite-source effects. Our primary analysis leads to the conclusion that the host of Jovian planet OGLE-2005-BLG-071Lb is a foreground M dwarf, with mass M = 0.46 +/- 0.04 Msun, distance D_lens = 3.3 +/- 0.4 kpc, and thick-disk kinematics v_LSR ~ 103 km/s. From the best-fit model, the planet has mass M_p = 3.5 +/- 0.3 M_Jup, lies at a projected separation r_perp = 3.6 +/- 0.2 AU from its host and has an equilibrium temperature of T ~ 50 K, i.e., similar to Neptune. A degenerate model less favored by \Delta\chi^2 ~ 4 gives essentially the same planetary mass M_p = 3.3 +/- 0.4 M_Jup with a smaller projected separation, r_perp = 2.1 +/- 0.1 AU, and higher equilibrium temperature T ~ 70 K. These results from the primary analysis suggest that OGLE-2005-BLG-071Lb is likely to be the most massive planet yet discovered that is hosted by an M dwarf. However, the formation of such high-mass planetary companions in the outer regions of M-dwarf planetary systems is predicted to be unlikely within the core-accretion scenario. There are a number of caveats to this analysis, but these could mostly be resolved by a single astrometric measurement a few years after the event.

Star:
mass = 0.46 solar masses.
distance = 3.3 kiloparsecs

Planet:
mass = 3.5 Jupiter masses.
altitude = 3.6 AU

This makes OGLE-2005-071L b the most massive planet found orbiting a red dwarf star. It's becomming rather apparent that low mass stars favor low mass planets.
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