More About GJ 1132b

Having been discovered last year, we've said hello to GJ 1132b. Since then, it has been one of the most highly characterized small exoplanets currently known. It is located just 39 light-years away from Earth, orbiting a relatively dim star at a distance of 2.2 million km (1.4 million miles).

In a recent study, a team of astronomers tell us another interesting thing about GJ 1132b. Despite having an intense surface temperature of about 232°C (450°F), it is possible that the exoplanet has an atmosphere that is thin and wispy.

Laura Schaefer, astronomer from Harvard-Smithsonian Center for Astrophysics and lead author of the study, together with her colleagues, investigated the interaction of a magma ocean with a water-rich atmosphere and created a model to simulate the interaction.

Image credit: Karl Tate

The Magma Ocean-Atmosphere Interaction

GJ 1132b orbits so close its star (about 30 times closer than the distance between Mercury and the Sun) that it is flooded with ultraviolet light, which breaks water molecules into hydrogen and oxygen. Hydrogen, being lighter in weight between the two, gets lost into space more quickly, while oxygen stays behind.

Schaefer said in a statement: “On cooler planets, oxygen could be a sign of alien life and habitability. But on a hot planet like GJ 1132b, it’s a sign of the exact opposite — a planet that’s being baked and sterilized.”

Moreover, the water vapor — which is a greenhouse gas — intensifies the planet’s extreme heat, which makes the planet an ocean of magma and allows it to remain molten for millions of years. And according to the model done by the team, although the magma ocean interacts with the atmosphere, it only absorbs ten percent of the oxygen, and most of the remaining 90% streams off into space although some might stay behind.

Scientists believe that the magma ocean-atmosphere model could help astronomers and researchers understand how Venus evolved over time.

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