Multi-scale accretion in dense cloud cores and the delayed formation of massive stars. (arXiv:2306.13846v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Vazquez_Semadeni_E/0/1/0/all/0/1">Enrique Vázquez-Semadeni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gomez_G/0/1/0/all/0/1">Gilberto C. Gómez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gonzalez_Samaniego_A/0/1/0/all/0/1">Alejandro González-Samaniego</a>
The formation mechanism of massive stars remains one of the main open problem
in astrophysics, in particular the relationship between the mass of the most
massive stars, and that of the cores in which they form. Numerical simulations
of the formation and evolution of large molecular clouds, within which dense
cores and stars form self-consistently, show in general that the cores’ masses
increase in time, and also that the most massive stars tend to appear later (by
a few to several Myr) than lower-mass stars. Here we present a model that
incorporates accretion onto the cores as well as onto the stars, in which the
core’s mass grows by a “gravitational choking” mechanism that does not
involve any form of support. This process is of purely gravitational origin,
and causes some of the mass accreted onto the core to stagnate there, rather
than being transferred to the central stars. Thus, the simultaneous mass growth
of the core and of the stellar mass can be computed. In addition, we estimate
the mass of the most massive allowed star before its photoionizing radiation is
capable of overcoming the accretion flow onto the core. This model constitutes
a proof-of-concept for the simultaneous growth of the gas reservoir and the
stellar mass, the delay in the formation of massive stars observed in
cloud-scale numerical simulations, the need for massive, dense cores in order
to form massive stars, and the observed correlation between the mass of the
most massive star and the mass of the cluster it resides in. Also, our model
implies that by the time massive stars begin to form in a core, a number of
low-mass stars are expected to have already formed.
The formation mechanism of massive stars remains one of the main open problem
in astrophysics, in particular the relationship between the mass of the most
massive stars, and that of the cores in which they form. Numerical simulations
of the formation and evolution of large molecular clouds, within which dense
cores and stars form self-consistently, show in general that the cores’ masses
increase in time, and also that the most massive stars tend to appear later (by
a few to several Myr) than lower-mass stars. Here we present a model that
incorporates accretion onto the cores as well as onto the stars, in which the
core’s mass grows by a “gravitational choking” mechanism that does not
involve any form of support. This process is of purely gravitational origin,
and causes some of the mass accreted onto the core to stagnate there, rather
than being transferred to the central stars. Thus, the simultaneous mass growth
of the core and of the stellar mass can be computed. In addition, we estimate
the mass of the most massive allowed star before its photoionizing radiation is
capable of overcoming the accretion flow onto the core. This model constitutes
a proof-of-concept for the simultaneous growth of the gas reservoir and the
stellar mass, the delay in the formation of massive stars observed in
cloud-scale numerical simulations, the need for massive, dense cores in order
to form massive stars, and the observed correlation between the mass of the
most massive star and the mass of the cluster it resides in. Also, our model
implies that by the time massive stars begin to form in a core, a number of
low-mass stars are expected to have already formed.
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