Spectroscopic evidence for a range in abundances among faint subgiantstars in the globular cluster OME Cen.
Abstract
Intermediate dispersion spectra are presented for 11 stars on the lower subgiant branch of Omega Cen having B values in the range 16.7-18.4. Five of the stars have radial velocities incompatible with cluster membership, while of the remaining six probable members, five have M/H abundances in the -1.0 to -1.5 range and show signs of carbon depletion. The sixth object, with an M/H value of about -0.5, has an enhanced nitrogen abundance whose factor may be as high as 3.0. The possible reasons for this variation in nitrogen abundance considered are: (1) mixing of the stars during their evolution; (2) differences in abundance at the time of star formation; (3) accretion of material lost by the cluster red giants, and (4) accretion of material lost by a binary comparison.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 1981
- DOI:
- 10.1086/159324
- Bibcode:
- 1981ApJ...249..637B
- Keywords:
-
- Abundance;
- Globular Clusters;
- Late Stars;
- Stellar Spectra;
- Subgiant Stars;
- Carbon;
- Nitrogen;
- Radial Velocity;
- Red Giant Stars;
- Spectrum Analysis;
- Stellar Evolution;
- Stellar Mass Accretion;
- Astrophysics