Star formation in BOK globules and low-mass clouds.

Optical and IR photometry, together with red and blue spectra, show that Bernes 135 is a premain-sequence star of about 50 solar luminosities, 2.5-3 solar masses, and an effective temperature of 6800 K. While Bernes 135 is associated with the cometary globule CG 1 in the Gum Nebula, Bernes 136 is associated with the cometary globule CG 13 and is an early F-type field star whose radial velocity relative to the globule is 25.9 km/sec. While the main present source of UV radiation in the Gum Nebula is Zeta Puppis, the evaporation of the globules is not efficient enough to fully destroy any but the smallest modules during the remaining lifetime of Zeta Puppis. A scenario for module formation and evolution is suggested in which UV radiation from a massive O-star can destroy small neighboring clouds and separate less dense cloud material from cloud cores.