Poster Presentation

Searching for Possible Members of Beta Pictoris Moving Group in the Kepler Field

Chang-Yao CHEN (Department of Physics, NCU), Wen-Ping CHEN (Institute of Astronomy, NCU)

Most if not all stars are formed in clustered environments in molecular clouds. Star clusters eventually dissolve and supply the disk stellar population. Stellar moving groups are living fossils of how the disintegration process takes place. So far there are a handful of moving groups known, including the Beta Pictoris moving group (BPMG), which consists of 55 known stellar systems sharing similar space motion as Beta Pictoris, the prototypical star with a planetary debris disk. Based on the mean space motion of known members, and assuming a range of heliocentric distances, we computed the proper motion and radial velocity expected for a member toward any line of sight in the whole sky. On the basis of UCAC4 proper motion and the photometric distance, we have identified about 750 BPMG candidates in the Kepler Field of a 105 square degrees region in Lyra and Cygnus. While most of these candidates have no radial velocity measurements, 17 candidates show consistent LAMOST radial velocities. There are four candidates with no radial velocity data but are ROSAT X Ray sources indicative of possible stellar youth. Even though the radial velocity provides an additional constraint on membership, variation caused by binary orbital motion should be first excluded, i.e., measurements at different epochs are required. We are in the process of taking spectra of those 17 candidates with only single-epoch LAMOST data, in order to derive the radial velocity, to obtain the spectra type (for a better estimate of the distance), and to detect possible indication of stellar activity or youth. We will present the current status of the program.