Phys.org 12/15/2019
The discovery of terrestrial exoplanets, planets that orbit stars outside the solar system, has been one of the most significant developments in modern astronomy. Several exoplanets lie in the "habitable zones" of stars, where planets are thought to be able to maintain liquid water on their surface, and have the potential to host life. However, an exoplanet that is too close to its host star is highly sensitive to radiation bursts from the star, also known as flares.
In this new study, NYUAD Center for Space Science Research Scientist Dimitra Atri found that not all exoplanets in habitable zones will be able to maintain hospitable conditions for life. Exoplanets in close proximity to stars are subject to radiation bursts which can disrupt habitable conditions unless the exoplanet has significant atmospheric or magnetic shielding.
In the study, published in the journal Monthly Notices of the Royal Astronomical Society: Letters, Atri explores how flares from stars affect a planet's surface radiation dose, and if that can disrupt the planet's ability to host life. The role of a planet's magnetic field strength and its atmosphere in providing shielding from these bursts was also examined. The factors measured include flare strength and spectrum, as well as the planetary atmospheric density and magnetic field strength. To calculate the surface radiation dose, particle spectra from 70 major flare emitting events (observed between 1956 and 2012) were used as proxy, and the GEANT4 Monte Carlo model was used to simulate flare interaction with exoplanetary atmospheres.
More:
https://phys.org/news/2019-12-exoplanets-habitable-stars-flares.html
