New class of exoplanet! Half-rock, half-water worlds could be abodes for life

[Admin]

A new type of exoplanet, one made half of rock and half of water, has been discovered around the most common stars in the universe. The find may have great consequences in the search for alien life.

New class of exoplanet! Half-rock, half-water worlds could be abodes for life : Read more

 

[rod]

Models are good but solid verification is needed too.

The report states, "The fact that red dwarfs are so very common has made scientists wonder if they might be the best chance for discovering planets that can possess life as we know it on Earth. For example, in 2020, astronomers that discovered Gliese 887, the brightest red dwarf in our sky at visible wavelengths of light, may host a planet within its habitable zone, where surface temperatures are suitable to host liquid water."

Using the exoplanet.eu site, shows 352 to 468 K for Gliese 887 b and c exoplanets. The Extrasolar Planet Encyclopaedia — GJ 887 b (exoplanet.eu)

 

[Unclear Engineer]

Those temperatures seem awfully hot for life like we know it on Earth. I guess at high pressures, life might be able to deal with that, considering life on Earth at various geothermal vents.

But, maybe this is one of those things that isn't intuitively obvious.

So, I will ask, using the same predictive model, what is the calculated temperature for Earth, given the Sun's size and temperature and the Earth's orbital radius?

 

[rod]

Those temperatures seem awfully hot for life like we know it on Earth. I guess at high pressures, life might be able to deal with that, considering life on Earth at various geothermal vents.

But, maybe this is one of those things that isn't intuitively obvious.

So, I will ask, using the same predictive model, what is the calculated temperature for Earth, given the Sun's size and temperature and the Earth's orbital radius?

The exoplanet.eu site has links explaining how the temperatures were reported. Here is an example for GJ 887.

A multiple planet system of super-Earths orbiting the brightest red dwarf star GJ887, https://arxiv.org/abs/2006.16372, "The nearest exoplanets to the Sun are our best possibilities for detailed characterization. We report the discovery of a compact multi-planet system of super-Earths orbiting the nearby red dwarf GJ 887, using radial velocity measurements. The planets have orbital periods of 9.3 and 21.8~days. Assuming an Earth-like albedo, the equilibrium temperature of the 21.8 day planet is approx 350 K; which is interior, but close to the inner edge, of the liquid-water habitable zone. We also detect a further unconfirmed signal with a period of 50 days which could correspond to a third super-Earth in a more temperate orbit. GJ 887 is an unusually magnetically quiet red dwarf with a photometric variability below 500 parts-per-million, making its planets amenable to phase-resolved photometric characterization."

So, the standard uses an *Earth-like albedo* to determine the temperatures. The paper reports,
"Assuming an albedo, α, similar to Earths (α = 0.3), the equilibrium temperature, Teq, of the planets b and c would be 468 K and 352 K respectively."