Martayan, C. ; Zorec, J. ; Frémat, Y. ; Ekström, S.

published in Astronomy and Astrophysics, 516, pp. A103 (2010)

Abstract: Context. The identification of long-gamma-ray-bursts (LGRBs) is still uncertain, although the collapsar engine of fast-rotating massive stars is gaining a strong consensus. Aims: We propose that low-metallicity Be and Oe stars, which are massive fast rotators, as potential LGRBs progenitors. Methods: We checked this hypothesis by 1) testing the global specific angular momentum of Oe/Be stars in the ZAMS with the SMC metallicity; 2) comparing the ZAMS (Ω/Ωc,M/M⊙) parameters of these stars with the area predicted theoretically for progenitors with metallicity Z = 0.002; and 3) calculating the expected rate of LGRBs/year/galaxy and comparing them with the observed ones. To this end, we determined the ZAMS linear and angular rotational velocities for SMC Be and Oe stars using the observed V sin i parameters, corrected from the underestimation induced by the gravitational darkening effect. Results: The angular velocities of SMC Oe/Be stars are on average

DOI: 10.1051/0004-6361/200913079
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