Astronomy and Astrophysics – Astrophysics
Scientific paper
Jun 1978
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1978apj...222..621c&link_type=abstract
Astrophysical Journal, Part 1, vol. 222, June 1, 1978, p. 621-626. Research sponsored by the U.S. Department of Energy and Nati
Astronomy and Astrophysics
Astrophysics
39
Abundance, Cepheid Variables, Stellar Atmospheres, Stellar Mass, Stellar Winds, Convection, Helium, Hertzsprung-Russell Diagram, Light Curve, Periodic Variations, Stellar Motions, Stellar Temperature, Velocity Measurement
Scientific paper
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.
Cox Arthur N.
Hodson Stephen W.
Michaud Georges
No associations
LandOfFree
Cepheid masses and Cepheid winds does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Cepheid masses and Cepheid winds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cepheid masses and Cepheid winds will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-787836