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An artist’s conception of HD 209458 b, an exoplanet whose atmosphere is torn away at more than 35,000 km / hour by the radiation of its nearby parent star. This hot Jupiter was the first alien world discovered via the transit method and the first planet to study its atmosphere. Credits: NASA / European Space Agency / Alfred Vidal-Madjar (Institut d’Astrophysique de Paris, CNRS)
- Planetary habitability, defined by the ability of a planet to support liquid water on its surface, is one of the most important concepts in exoplanet science.
- Exoplanets (planets that orbit stars outside our solar system) are subject to space weather conditions in the form of stellar flares, radiation emissions from stars.
- These emissions consist of extreme ultraviolet (XUV) photons and charged particles and can alter the exoplanet’s upper atmosphere. Current methods for determining a planet’s ability to sustain life do not take stellar activity into consideration.
In a new study, researchers, led by researcher Dimitra Atri of the Center for Space Science at NYU Abu Dhabi (NYUAD), identified which stars were most likely to host habitable exoplanets based on the calculated erosion rates of planetary atmospheres.
In the document entitled “Star rockets against luminosity: XUV-induced atmospheric escape and planetary habitability”, published in the journal Royal Astronomical Society Monthly Notices: Letters, Atri and graduate student Shane Carberry Mogan introduce the flare emissions data analysis process NASA‘S TESS (Transiting Exoplanet Survey Satellite) observatory.
More frequent and lower energy flashes have been found to have a greater impact on an exoplanet’s atmosphere than less frequent and higher energy flashes. The researchers also determined how different types of stars extreme ultraviolet radiation (XUV) through stellar flare and how nearby planets are affected.
The ability to sustain an atmosphere is one of the most important requirements for a habitable planet. This research provides new insight into the habitability of exoplanets, as the effects of stellar activity were not well understood. This study also highlights the need for better numerical modeling of atmospheric escape – how planets release atmospheric gases into space – as it can lead to erosion of the atmosphere and decrease in the planet’s habitability.
“Given the proximity of exoplanets to host stars, it is critical to understand how space weather events linked to those stars can affect the exoplanet’s habitability,” said Atri. “The next step in the research would be to expand our dataset to analyze stellar flares from a wider variety of stars to see the long-term effects of stellar activity and to identify more potentially habitable exoplanets.”
Reference: “Stellar Flares Versus Luminosity: XUV-Induced Atmospheric Escape and Planetary Habitability” Royal Astronomical Society Monthly Notices: Letters.
DOI: 10.1093 / mnrasl / slaa166
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