XO-2b: Transiting Hot Jupiter in a Metal-rich Common Proper Motion Binary

Abstract

We report on a V=11.2 early K dwarf, XO-2 (GSC 03413-00005), that hosts a Rp=0.98+0.03/-0.01 Rjup, Mp=0.57+/-0.06 Mjup transiting extrasolar planet, XO-2b, with an orbital period of 2.615857+/-0.000005 days. XO-2 has high metallicity, [Fe/H]=0.45+/-0.02, high proper motion, mu_tot=157 mas/yr, and has a common proper motion stellar companion with 31" separation. The two stars are nearly identical twins, with very similar spectra and apparent magnitudes. Due to the high metallicity, these early K dwarf stars have a mass and radius close to solar, Ms=0.98+/-0.02 Msolar and Rs=0.97+0.02/-0.01 Rsolar. The high proper motion of XO-2 results from an eccentric orbit (Galactic pericenter, Rper<4 kpc) well confined to the Galactic disk (Zmax~100 pc). In addition, the phase space position of XO-2 is near the Hercules dynamical stream, which points to an origin of XO-2 in the metal-rich, inner Thin Disk and subsequent dynamical scattering into the solar neighborhood. We describe an efficient Markov Chain Monte Carlo algorithm for calculating the Bayesian posterior probability of the system parameters from a transit light curve.

14 pages, 10 Figures, Accepted in ApJ. Negligible changes to XO-2 system properties. Removed Chi^2 light curve analysis section, and simplified MCMC light curve analysis discussion

References in corpus (10)

• alpha-, r-, and s-process element trends in the Galactic thin and thick disks
• WASP-1b and WASP-2b: Two new transiting exoplanets detected with SuperWASP and SOPHIE
• HAT-P-1b: A Large-Radius, Low-Density Exoplanet Transiting one Member of a Stellar Binary
• Properties of planets in binary systems. The role of binary separation
• Close encounters in young stellar clusters: implications for planetary systems in the solar neighbourhood
• The AGN and Gas Disk in the Low Surface Brightness Galaxy PGC045080
• The Challenge of Wide-Field Transit Surveys: The Case of GSC 01944-02289
• The Chemical Compositions of Stars with Planets: A Review
• Kinematics of planet-host stars and their relation with dynamical streams in the solar neighbourhood
• Planets in binary systems: is the present configuration indicative of the formation process?

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