High-luminosity stars and the structure of a spiral arm in M31
Abstract
The surface density and maximum luminosity of bright stars are found to rise steeply towards the inner edge of the spiral arm S4 of the Andromeda Nebula. All stars brighter than 20.25 magnitudes in S4 from clod OB 78 to OB 82 are measured, and the brightest stars are found to have -7.0 magnitudes along the inner edge, and about -5.5 magnitudes at 1-kpc distance from the edge, where the surface density is 10 times lower. S4 remains the only arm in which definitive evidence of an age and density gradient has been observed which supports the density-wave theory of spiral structure.
- Publication:
-
Pisma v Astronomicheskii Zhurnal
- Pub Date:
- June 1981
- Bibcode:
- 1981PAZh....7..259E
- Keywords:
-
- Andromeda Galaxy;
- Early Stars;
- Galactic Structure;
- Nebulae;
- Spiral Galaxies;
- Stellar Luminosity;
- Brightness Distribution;
- Gas Density;
- Stellar Evolution;
- Stellar Magnitude;
- Astronomy