What a rush
It completes an orbit every 37 days
think I'll stay here thanks, bit too much like a roller coaster for me :o)
NASA’s Transiting Exoplanet Survey Satellite (TESS) has stumbled across its first Earth-sized planet that lies within the habitable zone of a star. That means that the otherworldly object known as TOI 700 d ticks two boxes. The first being that its size is similar to Earth, which suggests that it has a solid, rocky surface. …
> TOI 700 d is the third outermost planet to orbit star TOI 700
Third outermost, so there are two planets further out?
> ... The first innermost planet
Redundant adjective is redundant?
> ... The second middle planet
Second middle? How many planets are in the middle?
Commas are important.
It’s also unknown if TOI 700 d’s tidal locking might negatively impact the chances of its habitability.
It means that the most probable habitable region is going to be somewhere around the terminator*, depending upon the planet's axial tilt. That region will have the most moderated temperature over the course of the 37-day year (although that average temperature will still depend upon how close to the inner or outer edge of the habitable zone the planet lies -- assuming it doesn't have a strongly elliptical orbit). The tidal-locking also suggests that the planet may not still have a spinning core, which means a greater probability of a magnetosphere incapable of shielding against solar flux (although red dwarfs emit fewer and less-energetic particles than does Earth's sun). Definitely lots of questions still left to answer.
*Not that terminator.
> assuming it doesn't have a strongly elliptical orbit
I'm not sure that's possible when tidally locked - the planet would have to a variable rate of rotation i.e. slowing down when farther away and speeding up when closer in. It would need to be a pretty powerful source of energy to do that to an earth-sized planet over a 30 day period.
Good point. If the tidal forces were that strong then the planet's surface would be subject to constant earthquakes, although they would actually be less intense at the terminator.
It just goes to show how difficult it could be to find a habitable planet, at least for a species that's evolved on a planet of one particular type.
"The tidal-locking also suggests that the planet may not still have a spinning core."
The opposite's the case. If you're phase locked, then your core gets tidally heated. So there should be enough energy to keep the dynamo ticking over. That's why Mercury (3:2 resonance) has a magnetic field. It's likely TOI 7000 d does as well.
It's the atmospheric effects that will be the killer.
Since there is obviously intelligent life on it and it is 1,300 light years away we can already predict what we would be seeing on the planets surface if our telescopes could "enhance" the image enough.
Basically we would be seeing the aliens deal with a bunch of Christian stuff. Bit boring really.
Within a few million years of the planet becoming tidally locked, all the moisture would be locked up in a permanent icecap on the dark side of the planet. The light side of the planet would be drier than the Atacama desert in Chile.
The lack of water vapor in the atmosphere would lead to the dark side being even colder as water vapor is a major greenhouse gas.
Not habitable - even the area around the terminator would be totally lacking in water.
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