What Would Happen if We Were About 1 pc Away from a Supermassive Black Hole?

Abstract

We consider a hypothetic planet with the same mass m, radius R, angular momentum S, oblateness J 2 , semimajor axis a, eccentricity e, inclination I, and obliquity ε of the Earth orbiting a main sequence star with the same mass M ⋆ and radius R ⋆ of the Sun at a distance r • ≃ 1 parsec pc from a supermassive black hole in the center of the hosting galaxy with the same mass M • of, say, M87 * . We preliminarily investigate some dynamical consequences of its presence in the neighbourhood of such a stellar system on the planet's possibility of sustaining complex life over the eons. In particular, we obtain general analytic expressions for the long-term rates of change, doubly averaged over both the planetary and the galactocentric orbital periods P b and P • , of e, I, ε, which are the main quantities directly linked to the stellar insolation. We find that, for certain orbital configurations, the planet's perihelion distance q = a (1 − e) may greatly shrink leading, in some cases, even to an impact with the star. Also I may notably change, with variations of the order even of tens of degrees. On the other hand, ε does not seem to be particularly affected, being shifted, at most, by ≃ 0.02 deg over a Myr. Our results strongly depend the eccentricity e • of the galactocentric motion. keywords gravitation − celestial mechanics − (galaxies:) quasars: supermassive black holes − planetary systems − extraterrestrial intelligence

The Habitability of the Galactic Bulge

“…A specific treatment has been reserved to the so called S-stars nearest to the Galactic center, with regard to their interaction with the supermassive black hole Sgr A*: even in such extreme case, it is not evident that the orbit of planets around such stars would be significantly affected [39][40][41][42].…”

The short-period S-stars S4711, S62, S4714 and the Lense-Thirring effect due to the spin of Sgr A$^\ast$

“…In principle, also other competing dynamical effects may bias a potential detection of the LT orbital precessions because of their mismodeling or unmodeling. One of them, generally impacting I, Ω, ω, is the Newtonian 3-body perturbation on the target S-star induced by other distant stars for which analytical expressions exist in the literature either for their double average over both P b and the longer orbital period of the perturber as well; see, e.g., Iorio (2020). The assessment of the systematic uncertainties in the LT measurement depends on the mismodeling in the mass m of the 3rd body and in its orbital parameters.…”

The Habitability of the Galactic Bulge

“…A specific treatment has been reserved to the so called S-stars nearest to the Galactic center, with regard to their interaction with the supermassive black hole Sgr A*: even in such extreme case, it is not evident that the orbit of planets around such stars would be significantly affected [39][40][41][42].…”