Journal or Book Title
We have imaged a 10° × 10° region of the Cepheus bubble in the J = 1-0 line of CO and the 21 cm line of atomic hydrogen. The CO emission defines a giant expanding shell 120 pc in diameter, which is similar to that seen in the IRAS sky maps. We estimate the total gas mass in the region to be ~4 × 105M☉. The total kinetic energy from the observed spread of velocities of the molecular clouds is ~1051ergs. We suggest that the members of earlier generations of massive stars in NGC 7160 are responsible for the origin of the Cepheus bubble. These stars created an expanding compressed shell of gas that became gravitationally unstable at an age of ~7 Myr. The members of the Cepheus OB2 association comprise the second, intermediate generation of stars in this region that formed as a consequence of this instability. The numerous color selected IRAS point sources represent the third and youngest generation of stars in this region. Our observations suggest the great importance of sequentially triggered star formation in the region of the Cepheus bubble.
Patel, NA; Goldsmith, PF; Heyer, MH; Snell, RL; and Pratap, P, "Origin and evolution of the Cepheus bubble" (1998). Astrophysical Journal. 645.