Unusual giant planet orbiting a low-mass star

2023-08-04 10:50:23

The planet Jupiter. The new planet is about the size of Jupiter and is what is known as a ‘warm Jupiter’, because its host is a cool, low-mass star. – UNIVERSITY OF BIRMINGHAM

MADRID, 4 Ago. (EUROPA PRESS) –

An international team of scientists has discovered an unusual Jupiter-sized planet orbiting a low-mass star called TOI-4860, located in the constellation of Corvus.

The newly discovered gas giant, named TOI-4860 b, is an unusual planet for two reasons: stars this low-mass are not expected to host planets like Jupiter, and the planet appears to be particularly enriched with heavy elements.

The study, led by astronomers at the University of Birmingham, is published in Monthly Notices of the Royal Astronomical Society.

The planet was initially identified using NASA’s Transiting Exoplanet Survey Satellite as a blob of brightness as it transited in front of its host star, but that data alone was insufficient to confirm it was a planet.

The team used the SPECULOOS Southern Observatory, located in the Atacama Desert in Chile, to measure the planetary signal at various wavelengths and validate the planetary nature. The astronomers also observed the planet just before and after it disappeared behind its host star and noted that there was no change in light, meaning the planet was not emitting anything. Finally, the team collaborated with a Japanese group using the Subaru Telescope in Hawaii. Together they measured the mass of the planet to fully confirm it.

George Dransfield, a PhD student at the University of Birmingham and co-author of the study, explains it’s a statement: “According to the canonical model of planet formation, the less mass a star has, the less massive the disk of material surrounding it.

“Since planets are created from that disk, it was expected that high-mass planets like Jupiter would not form. However, we were curious about this and wanted to check out planetary candidates to see if it was possible. TOI-4860 is our first confirmation and also the lowest-mass star to host such a high-mass planet.”

Amaury Triaud, Professor of Exoplanetology at the University of Birmingham who led the study, said: “I am forever grateful to the brilliant PhD students on our team for proposing to look at systems like TOI-4860. Their work has really paid off, as they planets as TOI-4860 they are vital to deepening our understanding of planet formation.

“A hint of what might have happened is hidden in the planetary properties, which seem particularly enriched in heavy elements. We have also detected something similar in the host star, so it is likely that an abundance of heavy elements catalyzed the planet formation process.”

The new gas giant takes about 1.52 days to complete a full orbit around its host star, but because its host is a cool, low-mass star, the planet itself can be referred to as a “warm Jupiter.” This is a subclass of planet that is of particular interest to astronomers looking to build on their initial observations and learn more about how these types of planets form.