The luminosity function of late-type giants in the bulge of M31
- Columbia Univ., New York (USA) Palomar Observatory, Pasadena, CA (USA)
Infrared photometry is reported for a sample of 572 luminous giants in the bulge of M31,500-1000 pc from the nucleus. In contrast to the nuclear bulge population of the Milky Way, the luminosity function of M31 giants extends to Mbol = -5.5 and lacks a sharp cutoff at mbol = -4.2. The K, J - K color-magnitude diagram shows a well-defined giant branch similar in color to that of the Milky Way bulge stars, but there are many stars redward of the main giant branch locus. It is suggested that the most luminous stars may be OH/IR stars or Mira variables; they are clearly a significant component of the population of evolved stars in the M31 bulge. The upper limit to the luminosites of the M31 bulge giants agrees with that derived for the longest period (800 day) Miras in the bulge of the Milky Way. The presence of so many stars a magnitude above the first giant branch tip poses difficulties for the idea that the entire M31 bulge is as old as the Milky Way globular clusters. 31 refs.
- OSTI ID:
- 5544498
- Journal Information:
- Astronomical Journal; (USA), Journal Name: Astronomical Journal; (USA) Vol. 101; ISSN 0004-6256; ISSN ANJOA
- Country of Publication:
- United States
- Language:
- English
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Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AGE ESTIMATION
COMPARATIVE EVALUATIONS
COORDINATES
ELECTROMAGNETIC RADIATION
GALAXIES
GIANT STARS
INFRARED RADIATION
LIMITING VALUES
LUMINOSITY
MILKY WAY
OPTICAL PROPERTIES
PHOTOMETRY
PHYSICAL PROPERTIES
POPULATIONS
RADIATIONS
RED GIANT STARS
SPECTROPHOTOMETRY
STAR CLUSTERS
STARS
VARIABLE STARS