This rocky ‘super-Earth’ may be a hard place for life to get a foothold.
Red dwarfs are by far the most common stars in the Milky Way, but their planets may have a hard time holding onto an atmosphere, in part because these somewhat erratic stars subject them to powerful blasts of radiation.
Assessing whether such planets have
atmospheres is difficult because they are light-years away from
Earth-and their light gets lost in the glare of their stars. So one team
of astronomers used data from 100 hours of observations by NASA’s
Spitzer Space Telescope, which focuses on infrared light, to study LHS
3844b, a nearby exoplanet which is 1.3 times Earth’s diameter.
LHS 3844b (artist’s rendition, above) was one of the first planets
discovered by NASA’s Transiting Exoplanet Survey Satellite At 50 light-years away, LHS 3844b is one of the closest exoplanets to
Earth and it also has one of the fastest orbits-11 hours.The team measured the brightness of the star-planet system as LHS 3844b moved around its orbit. From that, they could calculate the brightness of the planet-and hence its temperature. If LHS 3844b had an atmosphere, weather systems would transport heat around the planet and even out the distribution of temperature. But the team found that the planet is blisteringly hot directly under the noonday sun and close to absolute zero at midnight , suggesting little or no atmosphere spreading the heat, they report in Nature today.
This is just a single planet, but the results suggest finding a hospitable planet around a red dwarf may not be as easy as astronomers had hoped.
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