Abstract / Description of output
We show that photoevaporation of small gaseous exoplanets ("mini-Neptunes") in the habitable zones of M dwarfs can remove several Earth masses of hydrogen and helium from these planets and transform them into potentially habitable worlds. We couple X-ray/extreme ultraviolet (XUV)-driven escape, thermal evolution, tidal evolution, and orbital migration to explore the types of systems that may harbor such "habitable evaporated cores" (HECs). We find that HECs are most likely to form from planets with similar to 1 M-circle plus solid cores with up to about 50% H/He by mass, though whether or not a given mini-Neptune forms a HEC is highly dependent on the early XUV evolution of the host star. As terrestrial planet formation around M dwarfs by accumulation of local material is likely to form planets that are small and dry, evaporation of small migrating mini-Neptunes could be one of the dominant formation mechanisms for volatile-rich Earths around these stars. Key Words: Astrobiology-Extrasolar terrestrial planets-Habitability-Planetary atmospheres-Tides. Astrobiology 15, 57-88.
| Original language | English |
|---|---|
| Pages (from-to) | 57-88 |
| Number of pages | 32 |
| Journal | Astrobiology |
| Volume | 15 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 1 Jan 2015 |
Keywords / Materials (for Non-textual outputs)
- MAIN-SEQUENCE STARS
- LOW-MASS STARS
- EXTRASOLAR PLANETS
- TIDAL EVOLUTION
- ATMOSPHERIC CHEMISTRY
- DETERMINISTIC MODEL
- ORBITAL EVOLUTION
- THERMAL ESCAPE
- OCEAN-PLANETS
- GIANT PLANETS