The extra-mixing efficiency in very low metallicity RGB stars
نویسندگان
چکیده
منابع مشابه
Mass loss and very low-metallicity stars
Mass loss plays a dominant role in the evolution of massive stars at solar metallicity. After discussing different mass loss mechanisms and their metallicity dependence, we present the possibility of strong mass loss at very low metallicity. Our models at Z = 10−8 show that stars more massive than about 60 M⊙ may lose a significant fraction of their initial mass in the red supergiant phase. Thi...
متن کاملEvolution of rotating stars at very low metallicity
At very low metallicity, the effects of differential rotation have a more important impact on the evolution of stars than at high metallicity. Rotational mixing leads to the production of great quantities of helium and of primary N by massive stars. Rotation induces important mass loss and allows stars to locally strongly enrich the interstellar medium in CNO elements. Stars formed from interst...
متن کاملMass loss of rotating stars at very low metallicity
Some indirect observations, as the high fraction of Be stars†at low metallicity, or the necessity for massive stars to be important sources of primary nitrogen, seem to indicate that very metal poor stars were fast rotators. As a consequence of this fast rotation, these stars, contrarily to current wisdom, might lose large amounts of mass during their lifetime. In this paper, we review various ...
متن کاملRotational mixing in low-mass stars II. Self-consistent models of Pop II RGB stars
In this paper we study the effects of rotation in low-mass, low-metallicity RGB stars. We present the first evolutionary models taking into account self-consistently the latest prescriptions for the transport of angular momentum by meridional circulation and shear turbulence in stellar interiors as well as the associated mixing processes for chemicals computed from the ZAMS to the upper RGB. We...
متن کاملCan Extra Mixing in RGB and AGB Stars Be Attributed to Magnetic Mechanisms?
It is known that there must be some weak form of transport (called cool bottom processing, or CBP) acting in low mass RGB and AGB stars, adding nuclei, newly produced near the hydrogen-burning shell, to the convective envelope. We assume that this extra-mixing originates in a stellar dynamo operated by the differential rotation below the envelope, maintaining toroidal magnetic fields near the h...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2006
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:20066552