Quasi-stars: accreting black holes inside massive envelopes

By M. Begelman, E. Rossi, Philip Armitage. 2007

152 citations recorded by the source corpus.

We study the structure and evolution of ‘quasi-stars’, accreting black holes embedded within massive hydrostatic gaseous envelopes. These configurations may model the early growth of supermassive black hole seeds. The accretion rate on to the black hole adjusts so that the luminosity carried by the convective envelope equals the Eddington limit for the total mass, M*+MBH≈M*. This greatly exceeds the Eddington limit for the black hole mass alone, leading to rapid growth of the black hole. We use analytic models and numerical stellar structure calculations to study the structure and evolution of quasi-stars. We show that the photospheric temperature of the envelope scales as Tph∝M−2/5BHM7/20*, and decreases with time while the black hole mass increases. Once Tph < 104 K, the photospheric opacity drops precipitously and Tph hits a limiting value, analogous to the Hayashi track for red giants and protostars, below which no hydrostatic solution for the convective envelope exists. For metal-free (Population III) opacities, this limiting temperature is approximately 4000 K. After a quasi-star reaches this limiting temperature, it is rapidly dispersed by radiation pressure. We find that black hole seeds with masses between 103 and 104 M⊙ could form via this mechanism in less than a few Myr.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/3d019e99d2fbca3b4736102db8c51ea4abbcfb33

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Citations in the corpus

Ubiquitous seeding of supermassive black holes by direct collapse (2012, background): “The central BH then continues to accrete, embedded in an envelope ofgas, at super-Eddington efficiencies reaching a quasi-star state and collapsing into aM• = 104−5 M⊙ black hole (Begelman et al. 2008).”
FORMATION OF PRIMORDIAL SUPERMASSIVE STARS BY RAPID MASS ACCRETION (2013, background): “If a BH forms after the inner part of the star gravitationally collapses, a so-called quasi-star (Begelman et al. 2008) might emerge.”
Formation of supermassive black holes (2010, background): “…black hole, with mass of a few M , formed as a result of core-collapse subsequently grows via accretion from the bloated envelopes that result (‘quasistars’, an initially low-mass black hole embedded within a massive, radiation-pressure-supported envelope; see also Begelman et al, 2006, 2008).”
FORMATION RATES OF POPULATION III STARS AND CHEMICAL ENRICHMENT OF HALOS DURING THE REIONIZATION ERA (2009, background): “Redshift z ≈ 15 might thus be the most favorable period for the formation of quasi-stars (Begelman et al. 2008), which are however expected to reside preferentially in underdense environments, where winds are more unlikely to be present and pollute the IGM.”
Evolution of supermassive stars as a pathway to black hole formation (2009, methodology): “We refer readers to Begelman et al. (2008) for detailed discussion of quasi-star structure and evolution.”
Pathways to massive black holes and compact star clusters in pre-galactic dark matter haloes with virial temperatures ≳10 000 K (2008, background): “…of simulated haloes at the top of the figure and the disc show simulations described in RH08, the sketch of the quasi-star is based on that in Begelman et al. (2008) and the picture of the star cluster shows the globular cluster M80 (source:…”
Formation of Supermassive Black Hole Seeds (2016, background): “Schleicher et al. (2013) found that for ṁ ≥ 0.14 M⊙/yr the core of a SMS collapses into a BH and forms a so-called quasi-star, also see Begelman et al. (2008).”