On monolithic supermassive stars

Tyrone E. Woods, Alexander Heger, Lionel Haemmerlé

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10 Citations (Scopus)


Supermassive stars have been proposed as the progenitors of the massive (∼ 109 M☉) 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 kM☉. We find that stars born with masses between ∼ 60 and ∼ 150 kM☉ collapse at the end of the main sequence, burning stably for ∼ 1.5 Myr. More massive stars collapse directly through the general relativistic instability after only a thermal time-scale of ∼ 3-4 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.

Original languageEnglish
Pages (from-to)2236-2243
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
Publication statusPublished - May 2020


  • Early universe
  • Stars: massive
  • Stars: Population III

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