Abstract
Excitation of radial oscillations in population I (X = 0.7, Z = 0.02) red supergiants is investigated using the solution of the equations of radiation hydrodynamics and turbulent convection. The core helium burning stars with masses 8M ⊙ ≤ M ≤ 20M ⊙ and effective temperatures T eff < 4000 K are shown to be unstable against radial pulsations in the fundamental mode. The oscillation periods range between 45 and 1180 days. The pulsational instability is due to the κ-mechanism in the hydrogen and heliumionization zones. Radial pulsations of stars with mass M < 15M ⊙ are strictly periodic with the light amplitude ΔM bol ≤ 0ṃ5. The pulsation amplitude increases with increasing stellar mass and for M > 15M ⊙ the maximum expansion velocity of outer layers is as high as one third of the escape velocity. The mean radii of outer Lagrangean mass zones increase due to nonlinear oscillations by ≤30% in comparison with the initial equilibrium. The approximate method (with uncertainty of a factor of 1.5) to evaluate the mass of the pulsating red supergiant with the known period of radial oscillations is proposed. The approximation of the pulsation constant Q as a function of the mass-to-radius ratio is given. Masses of seven galactic red supergiants are evaluated using the period-mean density relation.
Similar content being viewed by others
References
Yu.A. Fadeyev, Pis’ma Astron. Zh. 37, 13 (2011a) [Astron. Lett. 37, 11 (2011a)].
Yu.A. Fadeyev, Pis’ma Astron. Zh. 37, 440 (2011b) [Astron. Lett. 37, 403 (2011b)].
M. W. Feast, R. M. Catchpole, D. S. Carter, et al., MNRAS 193, 377 (1980).
I. S. Glass, MNRAS 186, 317 (1979).
J. H. Guo and Y. Li, Astrophys. J. 565, 559 (2002).
A. Heger, L. Jeannin, N. Langer, et al., Astron. Astrophys. 327, 224 (1997).
E. Josselin and B. Plez, Astron. Astrophys. 469, 671 (2007).
J. S. Jurcevic, M. J. Pierce, and G. H. Jacoby, MNRAS 313, 868 (2000).
L. L. Kiss, Gy.M. Szabó, and T. R. Bedding, MNRAS 372, 1721 (2006).
R. Kuhfuß, 1986, Astron. Astrophys. 160, 116 (1986).
E. Levesque, P. Massey, K. A.G. Olsen, et al., Astrophys. J. 628, 973 (2005).
Y. Li and Z. G. Gong, Astron. Astrophys. 289, 449 (1994).
J. Th. van Loon, M. Cohen, J. M. Oliveira, et al., Astron. Astrophys. 487, 1055 (2008).
N. Mauron and E. Josselin, Astron. Astrophys. 526, A156 (2011).
H. Nieuwenhuijzen and C. de Jager, Astron. Astrophys. 231, 134 (1990).
M. J. Pierce, J. S. Jurcevic, and D. Crabtree, MNRAS 313, 271 (2000).
N. N. Samus, E. V. Kazarovets, N. N. Kireeva, et al., General Catalogue of Variable Stars (2011).
M. Schwarzschild, Astrophys. J. 195, 137 (1975).
R. Stothers, Astrophys. J 156, 541 (1969).
R. Stothers, Astron. Astrophys. 18, 325 (1972).
R. Stothers, Astrophys. J 725, 1170 (2010).
R. Stothers and K. C. Leung, Astron. Astrophys. 10, 290 (1971).
T. Verhoelst, N. Van der Zypen, S. Hony, et al., Astron. Astrophys. 498, 127 (2009).
S.-C. Yoon and M. Cantiello, Astrophys. J. 717, L62 (2010).
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text © Yu.A. Fadeyev, 2012, published in Pis’ma v Astronomicheskiĭ Zhurnal, 2012, Vol. 38, No. 4, pp. 295–306.
Rights and permissions
About this article
Cite this article
Fadeyev, Y.A. Nonlinear pulsations of red supergiants. Astron. Lett. 38, 260–270 (2012). https://doi.org/10.1134/S1063773712040032
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1063773712040032