Exoplanets – worlds of other suns

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Astrocomb breakthrough could help discover Earth-like planets

Friday 29 March 2024 00:24, UK



New Earth-like planets could soon be discovered after scientists made a technological breakthrough.

Physicists have developed an astrocomb that can analyse the blue-green light emitted by stars.

Astrocombs can detect tiny variations in a star's light created by orbiting exoplanets (those beyond our own solar system) - potentially revealing one similar to Earth.

They have been mainly limited to the green-red part of the light spectrum, but the new system offers the chance to uncover even more space secrets.

The breakthrough was made by physicists at Heriot-Watt University in Edinburgh and Cambridge University.

https://news.sky.com/story/astrocomb-br ... s-13103465

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JWST COMPASS: NIRSpec/G395H Transmission Observations of the Super-Earth TOI-836b
https://arxiv.org/abs/2404.00093

JWST COMPASS: NIRSpec/G395H Transmission Observations of the Super-Earth TOI-836c
https://arxiv.org/abs/2404.01264

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First tidally locked super-Earth exoplanet confirmed

by Bob Yirka , Phys.org

An international team of astronomers and astrophysicists has confirmed the first known observance of a tidally locked super-Earth exoplanet. In their paper published in The Astrophysical Journal, the group describes the unique approach they took to confirm that the exoplanet LHS 3844b is tidally locked and what the finding suggests about other planets in the galaxy.

Prior research has led astronomers to believe that some exoplanets are tidally locked, with one side that always faces the star they revolve around, but they have been unable until now to prove it. In this new effort, the research team picked a likely candidate and used a unique approach to study its attributes to ascertain its motion.

https://phys.org/news/2024-04-tidally-s ... lanet.html

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Searching for Free-Floating Planets with TESS: I. Discovery of a First Terrestrial-Mass Candidate
https://arxiv.org/abs/2404.11666

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Machine learning-based identification of Gaia astrometric exoplanet orbits
https://arxiv.org/abs/2404.09350
Quote :
The third Gaia data release (DR3) contains ∼170 000 astrometric orbit solutions of two-body systems located within ∼500 pc of the Sun. Determining component masses in these systems, in particular of stars hosting exoplanets, usually hinges on incorporating complementary observations in addition to the astrometry, e.g. spectroscopy and radial velocities. Several DR3 two-body systems with exoplanet, brown-dwarf, stellar, and black-hole components have been confirmed in this way. We developed an alternative machine learning approach that uses only the DR3 orbital solutions with the aim of identifying the best candidates for exoplanets and brown-dwarf companions. Based on confirmed substellar companions in the literature, we use semi-supervised anomaly detection methods in combination with extreme gradient boosting and random forest classifiers to determine likely low-mass outliers in the population of non-single sources. We employ and study feature importance to investigate the method's plausibility and produced a list of 22 best candidates of which four are exoplanet candidates and another five are either very-massive brown dwarfs or very-low mass stars. Three candidates, including one initial exoplanet candidate, correspond to false-positive solutions where longer-period binary star motion was fitted with a biased shorter-period orbit. We highlight nine candidates with brown-dwarf companions for preferential follow-up. One candidate companion around the Sun-like star G 15-6 could be confirmed as a genuine brown dwarf using external radial-velocity data. This new approach is a powerful complement to the traditional identification methods for substellar companions among Gaia astrometric orbits. It is particularly relevant in the context of Gaia DR4 and its expected exoplanet discovery yield.

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