The composition and evolutionary status of the helium-rich stars.
A spectroscopic investigation of recently discovered helium-rich B-type stars shows that they form a well-defined group with the characteristics: (1) helium abundances comparable to hydrogen by number; (2) temperatures indicative of B() B2 stars; (3) gravities appropriate to the zero-age main sequence; (4) generally low rotational velocities; (5) order-of-magnitude overabundances of oxygen and nitrogen; but (6) basically normal abundances of carbon, silicon, magnesium, and aluminum. The (g, 0 )-diagram for these stars suggests that they are hot analogs of the Bp (helium-weak) stars. We argue that this is with our understanding of mass-loss and diffusion processes in this region of the H-R diagram. Subject headings: abundances, stellar - atmospheres, stellar - early-type stars
The Astrophysical Journal
- Pub Date:
- January 1974