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Induction Heating Could Cause TRAPPIST-1 Exoplanets to Melt

Accepted submission by takyon at 2017-10-29 21:46:01
Science

Star's magnetic field could turn habitable-zone planets into magma soup [arstechnica.com]

[A] team of European researchers has identified something else that could have an immense effect on habitability: the star's magnetic field. Under the right conditions, planets close to a star will experience a strong but variable magnetic field, which can cause induction heating. In the case of one system with several habitable zone planets, the induction heating could be strong enough to convert them into oceans of magma.

[...] The European team behind the new report focused on M dwarf stars. Because these are small, relatively cool objects, their habitable zones are close to the star and well within the region where the star's magnetic field is quite strong. They also have magnetic fields that are strong to begin with, sometimes in the area of thousands of Gauss. The magnetic field of our Sun is typically 10 to 1,000 times weaker.

Not all M dwarfs rotate quickly enough for this to matter. Proxima Centauri, which hosts the closest known exoplanet, takes more than 80 days to complete a rotation. But there is a nearby M dwarf that completes a rotation in only three days: TRAPPIST-1, which hosts at least seven planets [arstechnica.com], three of them in the habitable zone. So, the team decided to model how much of an effect induction heating might have on these bodies.

[...] For TRAPPIST-1c, the third planet out from the star, induction heating reaches more than 60 percent of the heat released in the planet by radioactive decay. That's enough to melt the entire surface, turning it into a magma ocean in nearly all the different model conditions sampled. The same conditions are likely on TRAPPIST-1d, the one in the habitable zone, where induction heating can be above half the amount of heat released by radioactive decay.

Red dwarf exolife killer or a way to expand the habitable zone further out?

Magma oceans and enhanced volcanism on TRAPPIST-1 planets due to induction heating [nature.com] (DOI: 10.1038/s41550-017-0284-0) (DX [doi.org])

Previously: Seven Earth-Sized Exoplanets, Including Three Potentially Habitable, Identified Around TRAPPIST-1 [soylentnews.org]
Powerful Solar Flares Found at TRAPPIST-1 Could Dim Chances for Life [soylentnews.org]
TRAPPIST-1h Orbital Details Confirmed [soylentnews.org]
TRAPPIST-1 Older than Our Solar System [soylentnews.org]
Hubble Observations Suggest TRAPPIST-1 Exoplanets Could Have Water [soylentnews.org]


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