Researchers have found that alien life could not be found on exoplanets revolving around the cooling stars such as white dwarfs.
This research has been published online in the journal Astrobiology.
Researchers have found that the stars, especially white dwarfs and brown dwarfs, continuously shift habitable zones resulting in the change of distance important for the existence of liquid water leading to make it difficult for any type of life to exist there.
White dwarfs are small, dim and very much dense stars, which are collapsed in themselves and are in the final stages of evolution. Brown dwarfs are also small stars, even smaller than a planet with mass equivalent to one tenth of the Sun’s mass. Although, both of these types of stars produce enough radiation to develop habitable zones around them but as they cool down habitable zones move closer and closer with time. So, researchers are of the opinion that planet in the habitable zones of the white dwarf were present in the inner edge initially.
Due to the hot past, such planet would “face a difficult path to habitability,” study lead author Rory Barnes, of the University of Washington, said, even if they’re found in the habitable zone.
“These planets, if we find them today in a current habitable zone, previously had to have gone through a phase which sterilized them forever,” Barnes said in a statement.
“So, even if they are located in the habitable zone today, they are dead,” added co-author René Heller, of the Leibniz Institute for Astrophysics Potsdam in Germany.