Structure and Motions in the Carina Spiral Feature

Abstract

The distribution and kinematics of the luminous young stars in the Carina spiral feature (l = 282° - 305 °) are investigated and compared with the available data for the neutral hydrogen gas in the same region. New observational data are presented for 176 luminous stars of all spec- tral types. These stars reveal a well- defined spiral feature from 1.5 to 6 kpc from the sun. It is suggested that both the young stars and hydrogen gas are observed to large distances along the line of sight in Carina. A detailed comparison of the velocities of the stars and dense gas yields a good overall correlation. A noticeable discrepancy at l = 290° between the stellar and gas motions is discussed. Velocity residuals for the stars indicate systematic motions of 6 km /sec between the sides of the spiral feature. These streaming motions should be shared by the associated gas.