nasa, ESO, exoplanet, Proxima b,
This artist's impression shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the solar system.ESO/M. Kornmesser

An Earth-sized exoplanet named Proxima b-- which is just 4 light years away from our Solar System--- might not be habitable as presumed earlier.

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Red dwarfs like Proxima Centauri or the TRAPPIST-1 star are usually chosen as the target of exoplanet hunting as they are the coolest, smallest and also most common stars present in the galaxy. Tight orbits need to be maintained as they are cooler and dimmer for maintaining the presence of liquid water.

Here are the top things about the exoplanet:

  1. This exoplanet was discovered last August in the habitable zone of its star. The planet orbits Proxima Centauri, a red dwarf star.
  2. The Astrophysical Journal Letters revealed any planet with Earth's atmosphere will not survive at such close proximity to a red dwarf star due to its hazardous UV radiation. The radiation whittles down hydrogen and also, heavier elements like oxygen and nitrogen over time. This makes Proxima b highly uninhabitable.
  3. The exoplanet is not observed crossing the parent star, which makes it difficult for the astronomers to analyse whether the atmosphere is habitable or not. This research has been supported by NASA's NExSS – which is leading the search for life on planets beyond our solar system -- and the NASA Astrobiology Institute.
  4. "We decided to take the only habitable planet we know of so far — Earth — and put it where Proxima b is," said Katherine Garcia-Sage, a space scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the study, a NASA statement revealed.
  5. It was found that the radiation received by the exoplanet Proxima b by its star is hundred times stronger than what Earth receives from the Sun.
  6. "This was a simple calculation based on average activity from the host star," Garcia-Sage said. "It doesn't consider variations like extreme heating in the star's atmosphere or violent stellar disturbances to the exoplanet's magnetic field — things we'd expect provide even more ionizing radiation and atmospheric escape."
  7. "Things can get interesting if an exoplanet holds on to its atmosphere, but Proxima b's atmospheric loss rates here are so high that habitability is implausible," said Jeremy Drake, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics and co-author of the study.