Using mass-radius-composition models, small planets (R≲2R⊕) are typically classified into three types: iron-rich, nominally Earth-like, and those with solid/liquid water and/or atmosphere.
FGK stars
![Because of Kepler ’s poor sensitivity to habitable zone planets (around any star), the current sample does not offer evidence to support M dwarfs hosting more Earth-sized planets than FGK stars at habitable zone instellations. Top: The number of Earth-sized ([0.5, 1.5] R⊕) Kepler planet candidates orbiting M (solid blue), K (dashed orange), G (dot-dashed green) or F (dotted red) dwarf stars as a function of instellation. The shaded grey region denotes the regime where there are no detections of Earth-sized planets around F type stars, such that FGKM comparisons require models and/or extrapolations. Bottom: Earth-sized planet occurrence rates calculated via the reliability-weighted inverse detection efficiency method (Equation 4) over a continuum of habitable zone-width instellation bins. Vertical black dashed line represents the approximate point where the Petigura et al. (2022) occurrence distribution plateaus for [0.5, 0.7] M⊕ stars, indicating the regime where comparisons between spectral types would not be affected by differences in the break points of their power law distributions. -- astro-ph.SR](https://i0.wp.com/astrobiology.com/wp-content/uploads/2023/10/noevidence.png?resize=1200%2C719&ssl=1)
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report
No Evidence For More Earth-sized Planets In The Habitable Zone of Kepler’s M Versus FGK Stars
Reliable detections of Earth-sized planets in the habitable zone remain elusive in the Kepler sample, even for M dwarfs. The Kepler sample was once thought to contain a considerable number […]