文章基本信息

标题：Magnetic braking of supermassive stars through winds
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作者：L. Haemmerlé ; G. Meynet
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2019
卷号：623
DOI：10.1051/0004-6361/201935087
语种：English
出版社：EDP Sciences
摘要：Context. Supermassive stars (SMSs) are candidates for being progenitors of supermassive quasars at high redshifts. However, their formation process requires strong mechanisms that would be able to extract the angular momentum of the gas that the SMSs accrete.Aims. We investigate under which conditions the magnetic coupling between an accreting SMS and its winds can remove enough angular momentum for accretion to proceed from a Keplerian disc.Methods. We numerically computed the rotational properties of accreting SMSs that rotate at the ΩΓ-limit and estimated the magnetic field that is required to maintain the rotation velocity at this limit using prescriptions from magnetohydrodynamical simulations of stellar winds.Results. We find that a magnetic field of 10 kG at the stellar surface is required to satisfy the constraints on stellar rotation from the ΩΓ-limit.Conclusions. Magnetic coupling between the envelope of SMSs and their winds could allow for SMS formation by accretion from a Keplerian disc, provided the magnetic field is at the upper end of present-day observed stellar fields. Such fields are consistent with primordial origins.
关键词：enstars: massivestars: rotationstars: mass-lossstars: formationstars: magnetic fieldstars: Population III