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ye_olde_astronaut OP t1_j6jzlyh wrote

Reply to comment by Who_DaFuc_Asked in Habitable Planet Reality Check: TOI-700e Discovered by NASA’s TESS Mission by ye_olde_astronaut

> it's in the habitable zone of a red dwarf star (so it'll be tidally locked)

So? Taken directly from the linked article: "Increasingly detailed climate modeling over the last quarter century has shown that synchronous rotation is not the impediment to global habitability as it was once thought. In fact, it has been predicted that slow or synchronous rotation can actually result in an increase of the Seff corresponding to the inner edge of the HZ owing to feedback mechanisms which result in the formation of a reflective cloud layer on the perpetually daylit side of the planet."

> it is around the same diameter as the Earth, slightly more massive

No, according to the linked article the mass of TOI-700e is unknown. But, according to the linked article: "based on a statistical analysis by Chen & Kipping of the mass-radius relationship for exoplanets with known radii and masses, the estimated mass of TOI-700e is about 0.85 +0.67/-0.34 times that of the Earth"

So the most probable mass of TOI-700e is 0.85 times that of the Earth (not "slightly more massive" as you claim).

> it is pretty much on the very inner edge of the habitable zone

So? According to one of the references used in the linked article and by the discovery team of TOI-700e (R. K. Kopparapu et al. 2013), the inner edge of the habitable zone for the Sun is at about 0.97 AU. Earth, at a distance of 1.00 AU, is right at the inner edge of the habitable zone and is still habitable.

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QuasarMaster t1_j6mexnq wrote

Planets around red dwarfs are less likely to be habitable. Red dwarfs are far more temperamental than Sun-like stars, flaring often which irradiates nearby planets (which need to be very close in to be in the habitable zone).

https://en.wikipedia.org/wiki/Habitability_of_red_dwarf_systems

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ye_olde_astronaut OP t1_j6nglnq wrote

This is certainly true for smaller red dwarf stars, however there are other predictions that claim that it is not as big a problem as the more dire predictions would lead us to believe (never mind that there is a growing database of exoplanets orbiting red dwarfs that have low densities indicating that they have held onto their atmospheres and volatiles). More data is needed... which is why the linked paper (and other sources) refer to potential habitability.

That being said, TOI-700 is a larger and less active M2.5V red dwarf that would not have the same level of activity as smaller red dwarfs. Again, TOI-700e is potentially habitable and is a perfect target for future studies about the limits of planetary habitability.

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