The line-of-sight velocities of OB associations and molecular clouds in a wide solar neighborhood: The streaming motions of stars and gas in the Perseus arm

Abstract

We compare the line-of-sight velocities of stars in OB associations within 3 kpc of the Sun and the molecular clouds closest to them. The Perseus arm is used as an example to show that the line-of-sight velocity ranges in which OB-association stars, molecular clouds, and H II regions ionized by these association stars are observed overlap. The streaming motions produced by density waves in the (l, V LSR) plane were found to lead to an inversion of the distances to objects of the Perseus arm and the interarm space beyond this arm.