Estimating the intrinsic properties of miras from observational data

Journal Article · Sat Apr 01 04:00:00 EST 1978 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/156014· OSTI ID:6844147

Cahn, J H; Wyatt, S P

We explore several of the consequences of the model of late stellar evolution recently investigated by Wood and Cahn. As stars ascend the asymptotic giant branch in the H-R plane, they evolve from left to right in the (M, log L) -plane, and also sink downward as they suffer a steady stellar-wind mass loss of the Reimers type. Stars in the approximate range of 1--2 M/sub sun/ eventually evolve to the point where they apparently begin first-overtone oscillation; during this phase they are Mira variables for a few hundred thousand years. At the end of their Mira stage, many of these stars evolve directly to white dwarfs; the rest of them eject one or more planetary nebulae before entering white-dwarf territory. Higher-mass stars evolve across the (M, log L) -plane without ever penetrating the Mira region and go on directly to give rise to planetary nebulae and eventually become white dwarfs. Stars of even greater mass presumably end their migration across the (M, logL) -domain by becoming supernovae. We adopt this broad picture and go on first to the Mira variables, seeking to establish an empirical diagram of period of light variation against mean spectral type at maximum light. Curves of constant period and constant spectral type are superposed on the (M, logL) -plane, along with evolutionary tracks and time scales. Thus a knowlege of the observed mean spectral type at maximum light and the period of a star permits approximate estimates to be made of its mean bolometric luminosity and present mass and gives a bird's-eve view of its past and future evolutionary track.

• Research Organization: Department of Astronomy, University of Illinois at Urbana-Champaign
• OSTI ID: 6844147
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 221:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DIAGRAMS
DWARF STARS
HERTZSPRUNG-RUSSELL DIAGRAM
MAIN SEQUENCE STARS
NEBULAE
PLANETARY NEBULAE
STAR EVOLUTION
STARS
STELLAR WINDS
VARIABLE STARS
WHITE DWARF STARS