Habitable zones around almost extremely spinning black holes (black sun revisited)

Abstract

We analyzed the thermodynamics of hypothetical exoplanets at very low Keplerian circular orbits in close vicinity of rapidly spinning supermassive black holes. Such black hole exoplanets are heated by strongly blueshifted and focused flux of the incoming cosmic microwave background (CMB) and cooled by the cold part of the local sky containing the black hole shadow. This gives rise to a temperature difference, which can drive processes far from thermodynamic equilibrium in a hypothetical life form inhabiting black hole exoplanets, similar to the case of a planet heated by the radiation of the parent star and cooled by the night sky. We found that for a narrow range of radii of very low Keplerian circular orbits and for very high spin of a supermassive black hole, the temperature regime of the black hole exoplanets corresponds to the habitable zone around standard stars. The thermodynamics of black hole exoplanets therefore, in principle, does not exclude the existence of life based on known biology. The peak of the multiblackbody spectral profile of the CMB heating the exoplanet is located in the ultraviolet band, but a significant fraction of the flux comes also in the visible and infrared bands. The minimum mass of a black hole ensuring the resistance to tidal disruption of an Earth-like exoplanet orbiting in the habitable zone is estimated to $1.63\cdot 10^8{m}_{\odot }$.

arXiv comment13 pages, 7 figures

References in corpus (9)

• Habitable Zones Around Main-Sequence Stars: New Estimates
• Measuring Distance and Properties of the Milky Way's Central Supermassive Black Hole with Stellar Orbits
• The Temperature of the Cosmic Microwave Background
• Planck 2013 results. XXIII. Isotropy and statistics of the CMB
• The Shortest Known Period Star Orbiting our Galaxy's Supermassive Black Hole
• Black hole tidal problem in the Fermi normal coordinates
• Life under a black sun
• Twin peak HF QPOs as a spectral imprint of dual oscillation modes of accretion tori
• Cosmic background radiation in the vicinity of a Schwarzschild black hole: no classic firewall

Cited by in corpus (6)

• Silhouettes of invisible black holes
• The Habitability of the Galactic Bulge
• Eta-Earth Revisited II: Deriving a Maximum Number of Earth-like Habitats in the Galactic Disk
• Cosmic censorship conjecture in a general Kerr-Newman black hole
• Effects of the general relativistic spin precessions on the habitability of rogue planets orbiting supermassive black holes
• Visible shapes of black holes M87* and SgrA*