2010ApJ...723L.248K

We have used the Atacama Pathfinder Experiment 12 m telescope to detect circumstellar CO emission from MP Muscae (MP Mus; K1 IVe), a nearby (D ∼ 100 pc), actively accreting, ∼7 Myr old pre-main-sequence (pre-MS) star. The CO emission line profile measured for MP Mus is indicative of an orbiting disk with radius ∼120 AU, assuming that the central star mass is 1.2 M_☉ and the disk inclination is i ∼ 30°. The inferred disk molecular gas mass is ∼3 M_⊕. MP Mus thereby joins TW Hya and V4046 Sgr as the only late-type (low-mass), pre-MS star systems within ∼100 pc of Earth that are known to retain orbiting, molecular disks. We also report the nondetection (with the Institut de Radio Astronomie Millimetrique 30 m telescope) of CO emission from another 10 nearby (D ≲ 100 pc), dusty, young (age ∼10-100 Myr) field stars of spectral type A-G. We discuss the implications of these results for the timescales for stellar and Jovian planet accretion from, and dissipation of, molecular disks around young stars.