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Anders Johansen. Profile picture.

Anders Johansen

Professor

Anders Johansen. Profile picture.

TERRESTRIAL PLANETS ACROSS SPACE and TIME

Author

  • Erik Zackrisson
  • Per Calissendorff
  • Juan González
  • Andrew Benson
  • Anders Johansen
  • Markus Janson

Summary, in English

The study of cosmology, galaxy formation, and exoplanets has now advanced to a stage where a cosmic inventory of terrestrial planets (TPs) may be attempted. By coupling semianalytic models of galaxy formation to a recipe that relates the occurrence of planets to the mass and metallicity of their host stars, we trace the population of TPs around both solar-mass (FGK type) and lower-mass (M dwarf) stars throughout all of cosmic history. We find that the mean age of TPs in the local universe is 7 ± 1 Gyr for FGK hosts and 8 ± 1 Gyr for M dwarfs. We estimate that hot Jupiters have depleted the population of TPs around FGK stars by no more than ≈10%, and that only ≈10% of the TPs at the current epoch are orbiting stars in a metallicity range for which such planets have yet to be confirmed. The typical TP in the local universe is located in a spheroid-dominated galaxy with a total stellar mass comparable to that of the Milky Way. When looking at the inventory of planets throughout the whole observable universe, we argue for a total of ≈1 × 1019 and ≈5 × 1020 TPs around FGK and M stars, respectively. Due to light travel time effects, the TPs on our past light cone exhibit a mean age of just 1.7±0.2 Gyr. These results are discussed in the context of cosmic habitability, the Copernican principle, and searches for extraterrestrial intelligence at cosmological distances.

Department/s

  • Lund Observatory

Publishing year

2016-12-20

Language

English

Publication/Series

Astrophysical Journal

Volume

833

Issue

2

Document type

Journal article

Publisher

American Astronomical Society

Topic

  • Astronomy, Astrophysics and Cosmology

Keywords

  • cosmology: miscellaneous
  • extraterrestrial intelligence
  • galaxies: formation
  • planets and satellites: terrestrial planets

Status

Published

ISBN/ISSN/Other

  • ISSN: 0004-637X