To investigate moving groups of mira variables in the Solar neighborhood, we examined the proper motion data of SiO maser sources in the optical proper motion catalog, PPMXL. In addition to the previous SiO maser survey for red variables, we made a supplementary survey for optical variables using AAVSO catalog, and added 103 new accurate radial velocities of red variables in the sample. Proper motion data and period of light variation are available for almost all of these stars. From this basic set of SiO emitting objects, we selected 208 stars having high-quality proper motion data with an uncertainty of about 5 mas yr-1. Distances were deduced based on the period-luminosity relation. The longitude-proper motion diagram shows a clear Galactic rotation feature. Subtracting the corrections due to the QSO proper motion, the solar motion, and the Galactic rotation, we obtained residual velocities of stars to the local standard of rest. The Perseus group of stars shows average inward motion and rotational lag of 25 +- 11 km s-1 and 19 +- 8 km s-1, respectively. For other group of stars, no significant deviation from the Galactic rotation was found except the outward motion of the Hercules group of 63 +-9 km s-1, which was already revealed in the radial velocity data in the previous paper in some degree. New candidates for the Hercules group at l > 45 deg. were selected based on the radial velocity proper motion. |
Target sources:
2MASS
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