Statistics of Nearby Earth-like Planets Around M-dwarfs Stars

Here is an analysis on the frequency, number, distance, and probability of Earth-like planets (Earth-size within the habitable zone)around M-dwarf stars within 10 parsecs (~33 light years) from Earth. Table 1 shows these numbers for ηE (eta Earth) from four definitions of an Earth-like planet of Kopparapu (2013). These numbers assume that there are 248 M-dwarfs stars (RECONS) in 198 stellar systems (NSC) within 10 parsecs.

Table 1. Statistics of nearby Earth-like planets around M-dwarfs stars (see legend below for field definitions) for four definitions of Earth-like planet based on their size and orbit within a conservative or optimistic habitable zone.

pE10 ly = probability of an Earth-like planet within 10 light years from Earth.

dE 95% = distance from Earth for the 95% confidence level of an Earth-like planet.

In summary, there are over one-hundred Earth-like planets around M-dwarf stars within 10 parsecs from Earth. Just one or two are probably transiting (transiting probability of ~0.6-1.6%). This also means that there are over 67 to 134 billion Earth-like planets around low mass stars in our galaxy. Assuming that there are 200 to 400 billion stars in the Milky Way where 70% of those are low mass stars (0.1 to 0.8 solar masses) (Bochanski et al., 2010).