An international team of astronomers has discovered two new super-Earths orbiting distant ultracold dwarf stars 100 light-years from Earth.
newly discovered exoplanet Orbits the second coldest star with planets around it.The system’s inner planet, called LP 890-9b, is about 30 percent larger than Earth and orbits the dwarf star rapidly Star Just 2.7 Earth days. The second planet, called LP 890-9c, is slightly larger, about 40 percent the size of Earth, and completes its orbit in about 8.5 Earth days. Astronomers believe this second planet is in its star’s habitable zone, which is neither too hot nor too cold to support the existence of liquid water on its surface.
Inner planets were initially identified as exoplanet candidates by the Transiting Exoplanet Survey Satellite (Tess), seen from Earth, when exoplanets pass through the star’s surface, they find exoplanets, causing a slight drop in light output. Telescopes from the Search for Habitable Planets Obscure Ultracold Stars (SPECULOOS) project, operated by the University of Birmingham, UK, then confirmed (except for LP 890-9, which is sometimes referred to as TOI-4306 or SPECULOOS 2) to identify the two observers. )
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The SPECULOOS team then searched the system for more exoplanets, which revealed a second world that TESS missed.
“TESS searches for exoplanets using the transit method, by monitoring the brightness of thousands of stars simultaneously, looking for slight dimming that may be caused by a planet passing in front of its star,” said Laetitia Delrez, an exoplanet scientist at the University of Liege in Belgium and a co-author of the study. The lead author of a paper detailing the discovery, said in an article that statement (opens in new tab)“However, follow-up with ground-based telescopes is often required to confirm the planetary properties of detected candidates and to improve measurements of their size and orbital properties.”
This follow-up work is especially important for cool stars like LP 890-9, because most of their light is recorded in the infrared, and TESS has limited sensitivity.
This weakness is not present in the SPECULOOS project telescope, which is located on the island of Tenerife in western Chile and Morocco. These telescopes are equipped with cameras that are very sensitive to near-infrared light.
Michaël Gillon, an astronomer at the University of Liège and principal investigator of the SPECULOOS project, said in the same statement: “The goal of SPECULOOS is to find potentially habitable terrestrial planets passing through some of the smallest and coldest near the sun. “The motivation for this strategy is that such planets are particularly well suited for detailed studies of their atmospheres and the search for possible chemical traces of life through large observatories such as the James Webb Space Telescope (JWST).”
Gillon compared the discovery of these planets around the cold star LP 890-9 with the discovery of exoplanets. TRAPPIST-1 systemcentered on the coolest star ever discovered with a planet orbiting it.
Of the seven known exoplanets around TRAPPIST-1, three are in the habitable zone, making the system a prime target for deeper investigation. The fact that one of these newly discovered planets occupies the habitable zone of LP 890-9 makes further study of the system almost as attractive.
Amaury Triaud, an astrophysicist at the University of Birmingham and head of the SPECULOOS working group, said: “This allows us to make more observations and understand whether the planet has an atmosphere, and if so, to study its contents and assess its habitability. ” .
Next, the scientists hope to study SPECULOOS-2c’s atmosphere, possibly using the JWST, Recently detected carbon dioxide in the atmospheres of exoplanets.
“It is important to probe as many temperate terrestrial worlds as possible to study the diversity of exoplanet climates and ultimately to be able to measure how often biology occurs in the universe,” Triaud concluded.
The team’s findings were published Wednesday (September 6) in the journal Astronomy and Astrophysics.
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