Henry H. Hsieh , Bin Yang , Nader Haghighipour , Heather M. Kaluna , Alan Fitzsimmons , Larry Denneau , Bojan Novakovic , Robert Jedicke , Richard J. Wainscoat , James D. Armstrong , Samuel R. Duddy , Stephen C. Lowry , Chadwick A. Trujillo , Marco Micheli , Jacqueline V. Keane , Laurie Urban , Timm Riesen , Karen J. Meech , Shinsuke Abe , Yu-Chi Cheng , Wen-Ping Chen , Mikael Granvik , Tommy Grav , Wing-Huen Ip , Daisuke Kinoshita , Jan Kleyna , Pedro Lacerda , Tim Lister , Andrea Milani , David J. Tholen , Peter Veres , Carey M. Lisse , Michael S. Kelley , Yanga R. Fernandez , Bhuwan C. Bhatt , Devendra K. Sahu , Nick Kaiser , K. C. Chambers , Klaus W. Hodapp , Eugene A. Magnier , Paul A. Price , John L. Tonry
09 February 2012
Main belt asteroid (300163) 2006 VW139 (later designated P/2006 VW139) was discovered to exhibit comet-like activity by the Pan-STARRS1 survey telescope using automated point-spread-function analyses performed by PS1's Moving Object Processing System. Deep follow-up observations show both a short (\sim 10") antisolar dust tail and a longer (\sim 60") dust trail aligned with the object's orbit plane, similar to the morphology observed for another main-belt comet, P/2010 R2 (La Sagra), and other well-established comets, implying the action of a long-lived, sublimation-driven emission event. Photometry showing the brightness of the near-nucleus coma remaining constant over \sim 30 days provides further evidence for this object's cometary nature, suggesting it is in fact a main-belt comet, and not a disrupted asteroid. A spectroscopic search for CN emission was unsuccessful, though we find an upper limit CN production rate of Q_CN < 1.3x10^24 mol/s, from which we infer a water production rate of Q_H2O < 10^26 mol/s. We also find an approximately linear optical spectral slope of 7.2%/1000A, similar to other cometary dust comae. Numerical simulations indicate that P/2006 VW139 is dynamically stable for > 100 Myr, while a search for a potential asteroid family around the object reveals a cluster of 24 asteroids within a cutoff distance of 68 m/s. At 70 m/s, this cluster merges with the Themis family, suggesting that it could be similar to the Beagle family to which another main-belt comet, 133P/Elst-Pizarro, belongs.