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On monolithic supermassive stars

  • Woods, Tyrone E School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia
  • Heger, Alexander Australian Research Council Centre of Excellence for Gravitational Wave Discovery, Clayton, Victoria 3800, Australia
  • Haemmerlé, Lionel Département d’Astronomie, Université de Genève, Chemin des Maillettes 51, CH-1290 Versoix, Switzerland
  • 2020-3-19
Published in:
  • Monthly Notices of the Royal Astronomical Society. - Oxford University Press (OUP). - 2020, vol. 494, no. 2, p. 2236-2243
Space and Planetary Science
Astronomy and Astrophysics
English ABSTRACT
Supermassive stars have been proposed as the progenitors of the massive ($\sim \!10^{9}\, \mathrm{M}_{\odot }$) quasars observed at z ∼ 7. Prospects for directly detecting supermassive stars with next-generation facilities depend critically on their intrinsic lifetimes, as well as their formation rates. We use the one-dimensional stellar evolution code kepler to explore the theoretical limiting case of zero-metallicity non-rotating stars, formed monolithically with initial masses between $10$ and $190\, \mathrm{kM}_{\odot }$. We find that stars born with masses between $\sim\! 60$ and $\sim\! 150\, \mathrm{kM}_{\odot }$ collapse at the end of the main sequence, burning stably for $\sim\! 1.5\, \mathrm{Myr}$. More massive stars collapse directly through the general relativistic instability after only a thermal time-scale of $\sim\! 3$–$4\, \mathrm{kyr}$. The expected difficulty in producing such massive thermally relaxed objects, together with recent results for currently preferred rapidly accreting formation models, suggests that such ‘truly direct’ or ‘dark’ collapses may not be typical for supermassive objects in the early Universe. We close by discussing the evolution of supermassive stars in the broader context of massive primordial stellar evolution and the possibility of supermassive stellar explosions.
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  • English
Open access status
green
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https://sonar.ch/global/documents/171734
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