TY - JOUR
T1 - Evolution of galaxy habitability
AU - Gobat, R.
AU - Hong, S. E.
N1 - Publisher Copyright:
© ESO, 2016.
PY - 2016
Y1 - 2016
N2 - We combine a semi-analytic model of galaxy evolution with constraints on circumstellar habitable zones and the distribution of terrestrial planets in order to probe the suitability of galaxies of different mass and type to host habitable planets, and how it evolves with time. We find that the fraction of stars with terrestrial planets in their habitable zone (known as habitability) depends only weakly on galaxy mass, with a maximum around 4 × 1010M⊙. We estimate that 0.7% of all stars in Milky Way-type galaxies to host a terrestrial planet within their habitable zone, consistent with the value derived from Kepler observations. On the other hand, the habitability of passive galaxies is slightly but systematically higher, unless we assume an unrealistically high sensitivity of planets to supernovae. We find that the overall habitability of galaxies has not changed significantly in the last ∼8 Gyr, with most of the habitable planets in local disk galaxies having formed ∼1.5 Gyr before our own solar system. Finally, we expect that ∼1.4 ×109 planets similar to present-day Earth have existed so far in our galaxy.
AB - We combine a semi-analytic model of galaxy evolution with constraints on circumstellar habitable zones and the distribution of terrestrial planets in order to probe the suitability of galaxies of different mass and type to host habitable planets, and how it evolves with time. We find that the fraction of stars with terrestrial planets in their habitable zone (known as habitability) depends only weakly on galaxy mass, with a maximum around 4 × 1010M⊙. We estimate that 0.7% of all stars in Milky Way-type galaxies to host a terrestrial planet within their habitable zone, consistent with the value derived from Kepler observations. On the other hand, the habitability of passive galaxies is slightly but systematically higher, unless we assume an unrealistically high sensitivity of planets to supernovae. We find that the overall habitability of galaxies has not changed significantly in the last ∼8 Gyr, with most of the habitable planets in local disk galaxies having formed ∼1.5 Gyr before our own solar system. Finally, we expect that ∼1.4 ×109 planets similar to present-day Earth have existed so far in our galaxy.
KW - astrobiology
KW - galaxies: abundances
KW - galaxies: evolution
KW - galaxies: star formation
KW - planets and satellites: terrestrial planets
UR - http://www.scopus.com/inward/record.url?scp=84982850709&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201628834
DO - 10.1051/0004-6361/201628834
M3 - Article
AN - SCOPUS:84982850709
VL - 592
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
M1 - A96
ER -