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Astronomy Letters

, Volume 30, Issue 10, pp 707–714 | Cite as

Radial pulsations of helium stars with masses from 10 to 50M

  • Yu. A. Fadeyev
  • M. F. Novikova
Article

Abstract

We have performed hydrodynamic calculations of the radial pulsations of helium stars with masses 10MM ≤ 50M, luminosity-to-mass ratios 5 × 103L/ML/M ≤ 2.5 × 104L/M, and effective temperatures 2 × 104 K ≤ Teff ≤ 105 K for helium and heavy-element mass fractions of Y=0.98 and Z=0.02, respectively. We show that the high-temperature boundary of the instability region for radial pulsations at L/M ≳ 104L/M extends to Teff≈105 K. The amplitude of the velocity variations for outer layers is several hundred km s−1, while the brightness variations in the B band of the UBV photometric system are within the range from several hundredths to half a magnitude. At constant luminosity-to-mass ratio, the radial pulsation period is determined only by the effective temperature of the star. In the ranges of luminosity-to-mass ratios 104L/ML/M ≤ 2 × 104L/M and effective temperatures 5 × 104 K ≤ Teff ≤ 9 × 104 K, the periods of the radial modes are within 6 min ≲Π≲103 min.

Key words

stars—variable and peculiar stellar pulsations helium stars Wolf-Rayet stars 

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Copyright information

© MAIK "Nauka/Interperiodica" 2004

Authors and Affiliations

  • Yu. A. Fadeyev
    • 1
  • M. F. Novikova
    • 1
  1. 1.Institute of AstronomyRussian Academy of SciencesMoscowRussia

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