Occurrence of Earth-like planets around GKM Stars

Post date: Nov 05, 2013 4:12:47 PM

Here we combine and interpret results from Kopparapu (2013) and Petigura et al. (2013) on the occurrence of Earth-like planets around red-dwarf (type M) and Sun-like (type G and K) stars, respectively. Both studies used NASA Kepler results. Based on their occurrence estimates we calculated the mean separation and 95% confidence distance for the solar neighborhood (<10pc). These numbers suggest that there is over a 95% probability of finding an Earth-like planet around a Sun-like star in the solar neighborhood. The probability is higher for those around M-dwarf stars.

Table 1. Occurrence (ηE), separation (δE ), and 95% confidence distance (dE 95%) of Earth-like planets (0.5 — 2.0 RE in the HZ) around M-dwarfs and GK stars. The study of Petigura et al. (2013) only considered 1.0 — 2.0 RE planets. Calculations assume that there are 198 stellar systems with M-dwarf stars and 50 with GK-stars in the solar neighborhood (<10pc).

HZ References: (1) Kopparapu et al., 2013; (2) Petigura et al., 2013; (3) Zsom et al., 2013; Pierrehumbert and Gaidos, 2011

Table Notes:

a = semi-major axis (values shown for G stars, check here for other types of stars).

ηE (eta Earth) = fraction of Earth-like planets per star.

δE (delta Earth) = mean distance between stellar systems with Earth-like planets.

dE 95% = 95% confidence distance for an Earth-like planet.