Carbon stars in the Large Magellanic Cloud: photometry, spectroscopy, and evolutionary implications.
Abstract
Photometry and spectroscopy of an extensive sample of carbon stars in the Large Magellanic Cloud are presented. The data are used to define the region in the (r, R - I) color-magnitude diagram occupied by the carbon stars. The agreement of the observed blue boundary of the carbon-star occupation zone with the general shape and location of the theoretical prediction for the locus of the onset of helium shell flashes in double-shell-source stars points to this phenomenon as possibly related to carbon-star formation. The location of all the emission-line stars at the red edge of the color-magnitude diagram suggests that this phase may be terminal for carbon stars. Several natural spectroscopic groups are isolated; they are found to lie in distinct, well-defined regions of the color-magnitude and color-color diagrams. On the basis of these results, some tentative evolutionary implications are suggested. It is also shown that the majority of carbon stars from the catalog of Westerlund et al. (hereafter WORC) resemble disk carbon stars in our Galaxy whereas those from the catalog of Sanduleak and Philip not contained in WORC seem more typical of galactic halo objects such as CH stars. It is demonstrated that two carbon stars are probable members of the LMC cluster NOC 2209, and their properties are discussed. Subject headings: galaxies: Magellanic Clouds - stars: carbon
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1979
- DOI:
- 10.1086/157131
- Bibcode:
- 1979ApJ...230..724R
- Keywords:
-
- Carbon Stars;
- Hertzsprung-Russell Diagram;
- Magellanic Clouds;
- Stellar Evolution;
- Stellar Spectrophotometry;
- Astronomical Catalogs;
- Astronomical Photometry;
- Astronomical Spectroscopy;
- Astrophysics;
- C-M Diagrams:Carbon Stars;
- Carbon Stars:Magellanic Clouds;
- Carbon Stars:Photometry;
- Carbon Stars:Spectroscopy