Understanding the occurrence of Earth-sized planets in the habitable zone of Sun-like stars is essential to the search for analogues on Earth. However, the lack of reliable Kepler detections of such planets has forced many estimates to be derived from nearby populations (2
In this work, we calculate the intrinsic occurrence rates of the nearby super-Earths (∼1−2R⊕) and sub-Neptunes (∼2−3.5R⊕) of FGK stars (0.56−1.63M⊙) as a function of the orbital period and find evidence for two systems: where Super-Earths are more abundant at short orbital periods, and sub-Neptunes are more abundant at longer orbital periods. We fit a parametric model in five populated stellar mass bins and find that the orbital period of the transition between these two systems is of stellar mass, such as Ptrans M1.7 ± 0.2∗.
These results indicate the existence of a previous sub-Neptunian population that polluted the nearby super-Earth population of Gyr, indicative of a group formed by atmospheric loss. Using our model to constrain the population for long periods of intrinsically rocky planets, we estimate an incidence of Γ⊕ = 15 + 6−4% for Earth-size habitable zone planets, and predict that sub-Neptune ∼ will be twice as common as a super-Earth in the habitable zone (when normalized over the period of the orbital natural logarithm and the radius range used). Finally, we discuss our results in the context of future missions searching for habitable zone planets.
Galen J. Bergstein, Ilaria Pascucci, Jess de Mulders, and Rachel B.
Comments: 27 pages, 12 figures, 3 tables; Accepted for publication in AJ
Topics: Earth and Planetary Astrophysics (astro-ph.EP)
Cited as follows: arXiv: 2209.04047 [astro-ph.EP] (or arXiv: 2209.04047v1 [astro-ph.EP] for this version)
WHO: Galen Bergstein
[v1] Thursday, September 8, 2022 22:07:54 UTC (6,043 KB)