Cepheid masses and Cepheid winds

Abstract

view Abstract Citations (41) References (33) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Cepheid masses and Cepheid winds. Cox, A. N. ; Michaud, G. ; Hodson, S. W. Abstract Masses of Cepheids with bumps in their light and velocity curves (bump Cepheids) and those with two pulsation modes (beat or double-mode Cepheids) can be made equal to masses obtained from the evolution theory mass-luminosity relation if they have helium-enriched convection zones. The cause of this enrichment cannot be diffusion of helium from below with subsequent mixing in and between the H plus He I and He II convection zones. The probable cause of the composition inhomogeneity seems to be a Cepheid wind which depletes hydrogen more than helium as apparently occurs in the solar wind. A layer with Y equals 0.75 and Z equals 0.02 external to the 70,000 K level allows 7-solar-mass Cepheids to give the proper periods and light and velocity curve bumps at their evolution theory luminosity. This helium-deficient wind, if only a little stronger than that in the Sun, needs 1,000,000-10,000,000 years. Barely enough time is available for 7-solar-mass Cepheids, but there is plenty for the 4-5-solar-mass beat Cepheids to give their observed period ratios. Publication: The Astrophysical Journal Pub Date: June 1978 DOI: 10.1086/156178 Bibcode: 1978ApJ...222..621C Keywords: Abundance; Cepheid Variables; Stellar Atmospheres; Stellar Mass; Stellar Winds; Convection; Helium; Hertzsprung-Russell Diagram; Light Curve; Periodic Variations; Stellar Motions; Stellar Temperature; Velocity Measurement; Astrophysics; Cepheids:Masses; Cepheids:Stellar Winds full text sources ADS |