XO-5b: A TRANSITING JUPITER-SIZED PLANET WITH A 4 DAY PERIOD

The star XO-5 (GSC 02959-00729, V = 12.1, G8 V) hosts a Jupiter-sized, R-p = 1.15 +/- 0.12 R-J, transiting extra-solar planet, XO-5b, with an orbital period of 4.2 days. The planet's mass, Mp = 1.15 +/- 0.08 M-J, and surface gravity, g(p) = 22 +/- 5 m s(-2), are large for its orbital period compared to most other transiting planets. However, the deviation from the M-p-P relationship for XO-5b is not as large as for GJ 436b, HAT-P-2b, and XO-3b. By coincidence, XO-5 overlies the extreme H I plume that emanates from the interacting galaxy pair NGC 2444/NGC 2445 (Arp 143).