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Exoplanets (Extra-Solar Planets)

Probably not a good choice for colonising.

An alien world just 70 light-years from Earth is one of the strangest we have found yet.

It clocks in at 20 Jupiter masses, has temperatures that could quickly melt aluminum, and has a 10,000-year orbit around not one but two stars. And, oh yeah: It's ravaged by a constant, tempestuous storm of sand.

Astronomers have used the James Webb Space Telescope to obtain the most high-fidelity observations yet of the planetary-mass object, revealing roiling clouds of silicate grains circulating in the atmosphere of the world named VHS 1256 b.

The discovery, published last year on the preprint server arXiv, has gone through the peer review process and is due to appear in The Astrophysical Journal Letters.

In addition, the team identified many of the components of VHS 1256 b's atmosphere. Those include unambiguous detections of methane, carbon monoxide, and water, with additional evidence of carbon dioxide.

"No other telescope has identified so many features at once for a single target," says astrophysicist Paul Mollière of the Max Planck Institute for Astronomy in Germany. "We're seeing many molecules in a single spectrum from the JWST that detail the planet's dynamic cloud and weather systems."

https://www.sciencealert.com/astron...en-world-with-two-suns-and-a-raging-sandstorm
 
They never seem to find a planet on which the temperature, weather, gravity etc is like, say, 'Thanet' in Kent on a nice Tuesday afternoon in June.
They're always places that are on fire, or frozen, or all acid, or have rains of hot gravel......
 
They never seem to find a planet on which the temperature, weather, gravity etc is like, say, 'Thanet' in Kent on a nice Tuesday afternoon in June.
They're always places that are on fire, or frozen, or all acid, or have rains of hot gravel......
Still nicer than Thanet.
 
A water world?

A rare world 245 light-years away could be key to unraveling a planetary mystery.

An exoplanet called TOI-733b is just under twice the radius of Earth, and is orbiting a star a little smaller than the Sun with a period of 4.9 days. Measurements of its density suggest that it may either have lost its atmosphere, or be an ocean-covered water world.

At such a close orbital proximity, heat from the star is likely to be evaporating TOI-733b's atmosphere – which means that, in relatively short order, it could transform into a small, naked rock.

This, according to a team of astronomers led by Iskra Georgieva of Chalmers University of Technology in Sweden, could help scientists figure out a curious gap in the exoplanet record: why there are so few worlds between 1.5 and 2 Earth radii.

The research, accepted for publication in Astronomy & Astrophysics, is available on preprint server arXiv.

Since the first exoplanets were discovered in the 1990s, we've gone on to a sort of exoplanet discovery boom. At time of writing, over 5,300 exoplanets have been discovered and confirmed, along with thousands more candidates. All this means that we're able to start seeing some patterns emerge.

Some of those patterns are because of the way we look for exoplanets. The two primary methods are transits and radial velocity.

A transit observes the faint changes in starlight when an orbiting exoplanet passes between us and the star. Radial velocity measurements look for the tiny changes in starlight wavelength as the star is tugged by the exoplanet's gravity.

Both methods are better at detecting larger worlds in close orbits, so those make up most of the exoplanets we've found.

But some other patterns can't be explained by human technology. One glaring example is the small planet radius valley. We've found startlingly few worlds between the super-Earth category of exoplanets, up to 1.5 Earth radii, and mini-Neptunes, over 2 Earth radii.

https://www.sciencealert.com/we-may...-elusive-ocean-world-orbiting-a-sun-like-star
 
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