How red dwarfs could warm planets to sustain life
A new study has found how red dwarfs are likelier to support life than had been thought previously.
London: A new study led by an Indian origin researcher has found how red dwarfs, which constitute a vast majority of stars, are likelier to support life than had been thought previously.
Manoj Joshi from the University of Reading, UK, and Robert Haberle from NASA’s Ames Research Centre in California have found how these red dwarfs could warm far-off planets.
For the study, the researchers took spectral data for two red dwarfs known to have exoplanets, Gliese 436 and GJ 1214.
They found that ice and snow reflect 50 to 80 percent of visible light so the ice on Earth bounces most of sunlight back to space, and stays frozen but an icy planet would reflect 10 to 40 percent of the light it receives from the star.
“If there’s ice or snow on the ground, more of the radiation that hits the surface will be absorbed,” New Scientist quoted Joshi as saying.
“Which means that you’d expect it to be a lot hotter than it would be otherwise,” he said.
Compared with the Earth’s sun, red dwarfs shine less in visible wavelengths, and brighter in the near-infrared, which ice and snow soak up.
They also found that the outer edge of red dwarfs’ habitable zone is 10 to 30 percent further out from those stars than thought.
“You’ve got more area, more chance of getting a planet in the habitable zone,” he added.
The study work will be published in Astrobiology.