Hot super-Earths stripped by their host stars
M S Lundkvist1,2, H Kjeldsen1, S Albrecht1
1Stellar Astrophysics Centre (SAC), Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
Nature Communications
|April 12, 2016
Summary
Astronomers found a lack of hot super-Earth exoplanets, confirming theories that intense stellar radiation strips their atmospheres. This "super-Earth desert" provides crucial data for planetary system simulations.
Area of Science:
- Exoplanetary Science
- Stellar Astrophysics
- Planetary Formation
Background:
- Simulations suggest hot super-Earth exoplanets lose envelopes via photoevaporation.
- This atmospheric stripping should create an observable deficit in the exoplanet population.
- Previous observations have not definitively confirmed this predicted absence.
Purpose of the Study:
- To investigate the presence or absence of hot super-Earth exoplanets using asteroseismology.
- To test theoretical predictions of atmospheric stripping due to photoevaporation.
- To identify constraints for planetary system formation models.
Main Methods:
- Utilized asteroseismology data from the Kepler mission for exoplanet and candidate analysis.
- Analyzed exoplanets within a specific radius range (2.2–3.8 Earth radii).
- Correlated exoplanet occurrence with incident stellar flux.
Main Results:
- Confirmed an abundance of super-Earths at low incident fluxes.
- Found a significant lack of super-Earths with radii 2.2–3.8 Earth radii at high incident fluxes (>650 Earth insolation).
- This observed gap aligns with photoevaporation predictions.
Conclusions:
- The study confirms the existence of a "hot super-Earth desert".
- Atmospheric evaporation is the likely cause for the absence of close-in super-Earths.
- Findings provide critical observational constraints for planetary system evolution models.
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