Exoplanets – worlds of other suns

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JWST Directly Images Giant Planet Candidates Around Two Metal-Polluted White Dwarf Stars
https://arxiv.org/abs/2401.13153

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Hubble finds water vapor in small exoplanet's atmosphere
https://phys.org/news/2024-01-hubble-va ... e_vignette
by European Space Agency

Astronomers using the NASA/ESA Hubble Space Telescope observed the smallest exoplanet where water vapor has been detected in its atmosphere. At only approximately twice Earth's diameter, the planet GJ 9827d could be an example of potential planets with water-rich atmospheres elsewhere in our galaxy.

GJ 9827d was discovered by NASA's Kepler Space Telescope in 2017. It completes an orbit around a red dwarf star every 6.2 days. The star, GJ 9827, lies 97 light-years from Earth in the constellation Pisces.

"This would be the first time that we can directly show through an atmospheric detection that these planets with water-rich atmospheres can actually exist around other stars," said team member Björn Benneke of the Université de Montréal. "This is an important step toward determining the prevalence and diversity of atmospheres on rocky planets."

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Astronomers analyze masses, orbital properties and atmospheric features of six exoplanets
https://phys.org/news/2024-01-astronome ... heric.html
by University of California, Irvine

A recently discovered solar system with six confirmed exoplanets and a possible seventh is boosting astronomers' knowledge of planet formation and evolution. Relying on a globe-spanning arsenal of observatories and instruments, a team led by researchers at the University of California, Irvine has compiled the most precise measurements yet of the exoplanets' masses, orbital properties and atmospheric characteristics.

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New Wolf in the pack: Astronomers discover an ultra-short-period super-Earth
https://phys.org/news/2024-01-wolf-astr ... eriod.html
by Tomasz Nowakowski , Phys.org

Using NASA's Transiting Exoplanet Survey Satellite (TESS), an international team of astronomers has discovered a new ultra-short-period exoplanet. The newfound alien world, designated Wolf 327 b, is slightly larger and about 2.5 times more massive than the Earth. The finding was reported in a paper published January 22 on the pre-print server arXiv.

To date, TESS has identified over 7,000 candidate exoplanets (TESS Objects of Interest, or TOI), of which 415 have been confirmed so far. Since its launch in April 2018, the spacecraft has been conducting a survey of about 200,000 of the brightest stars near the sun with the aim of searching for transiting exoplanets—ranging from small, rocky worlds to gaseous giants.

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Neptune-like exoplanets can be cloudy or clear: New findings suggest the reason why
https://phys.org/news/2024-02-neptune-e ... loudy.html
by Brendan Lynch, University of Kansas

The study of "exoplanets," the sci-fi-sounding name for all planets in the cosmos beyond our own solar system, is a fairly new field. Mainly, exoplanet researchers like those in the ExoLab at the University of Kansas use data from space-borne telescopes such as the Hubble Space Telescope and Webb Space Telescope. Whenever news headlines offer findings of "Earth-like" planets or planets with the potential to support humanity, they're talking about exoplanets within our own Milky Way.

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Astronomers Find Potentially Habitable Super-Earth in Nearby Solar System
The planet is just 1.5 times Earth's diameter, orbiting its star every 19 Earth days.
By Ryan Whitwam February 5, 2024

https://www.extremetech.com/science/ast ... lar-system

Astronomers have detected a new super-Earth a mere 137 light-years away, and it's smack in the middle of the star's habitable zone. That's quite close in the grand scheme, and we have NASA's Transiting Exoplanet Survey Satellite (TESS) to thank. This world is bigger than Earth, but astronomers think there's a good chance it's rocky and ideal for observation with instruments like the James Webb Space Telescope.

The newly confirmed exoplanet is known as TOI-715b. It's only about 1.5 times the Earth's diameter but three times as massive. It orbits TOI-715 in just 19 days, which probably seems awfully close for a potentially habitable world. That's because TOI-715 is a small, cool red dwarf. These stars are the most common type in the Milky Way, and closely orbiting planets are easier to detect by transits. A single dip in brightness can be anything. Astronomers can only pick out potential exoplanet signatures after detecting a pattern of transits.

Because TOI-715b orbits so quickly, its transits are more visible and easier to track. NASA says red dwarf systems like this may be our best bet for identifying habitable worlds, and this is not the first super-Earth found orbiting a red dwarf. Finding a truly Earth-like world that orbits larger, brighter stars would take a long time with current technology. If TESS were looking at the Sun from a great distance, it might catch Earth's transit by luck, but it'd have to wait a year just to have a chance to see another. Building that data into even a preliminary exoplanet candidate would take multiple years. Other detection methods, like radial velocity, have similar limitations.

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Teegarden's Star revisited: A nearby planetary system with at least three planets
https://arxiv.org/abs/2402.00923

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TESS and ESPRESSO discover a super-Earth and a mini-Neptune orbiting the K-dwarf TOI-238
https://arxiv.org/abs/2402.04113

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Possible atmospheric destruction of a potentially habitable exoplanet

https://phys.org/news/2024-02-atmospher ... lanet.html