The star XO-5 ( GSC 02959-00729 , V=12.1 , G8V ) hosts a Jupiter-sized , R _ { p } =1.15 \pm 0.12 { R _ { J } } , transiting extrasolar planet , XO-5b , with an orbital period of 4.187732 \pm 0.00002 days .
The planet mass ( M _ { p } =1.15 \pm 0.08 { M _ { J } } ) and surface gravity ( g _ { p } =22 \pm 5 m s ^ { -2 } ) are significantly larger than expected by empirical M _ { p } -P and M _ { p } -P- [ Fe/H ] relationships .
However , the deviation from the M _ { p } -P relationship for XO-5b is not large enough to suggest a distinct type of planet as is suggested 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 ) .