We report observations of a possible young transiting planet orbiting a previously known weak-lined T-Tauri star in the 7– 10 { Myr } -old Orion-OB1a/25-Ori region .
The candidate was found as part of the Palomar Transient Factory ( PTF ) Orion project .
It has a photometric transit period of 0.448413 \pm 0.000040 days , and appears in both 2009 and 2010 PTF data .
Follow-up low-precision radial velocity observations and adaptive-optics imaging suggest that the star is not an eclipsing binary , and that it is unlikely that a background source is blended with the target and mimicking the observed transit .
Radial-velocity observations with the Hobby-Eberly and Keck telescopes yield a radial velocity that has the same period as the photometric event , but is offset in phase from the transit center by \approx - 0.22 periods .
The amplitude ( half range ) of the radial velocity variations is 2.4 { km } { s } ^ { -1 } and is comparable with the expected radial velocity amplitude that stellar spots could induce .
The radial velocity curve is likely dominated by stellar spot modulation and provides an upper limit to the projected companion mass of M _ { \mathrm { p } } \sin i _ { \mathrm { orb } } \lesssim 4.8 \pm 1.2 M _ { Jup } ; when combined with the orbital inclination , i _ { \mathrm { orb } } , of the candidate planet from modeling of the transit lightcurve , we find an upper limit on the mass of the planetary candidate of M _ { \mathrm { p } } \lesssim 5.5 \pm 1.4 M _ { Jup } .
This limit implies that the planet is orbiting close to , if not inside , its Roche limiting orbital radius , so that it may be undergoing active mass loss and evaporating .