New Earth-sized planet discovered orbiting star that will live for 100 billion years

Researchers using robotic global telescopes discovered an Earth-sized planet, SPECULOOS-3 b, orbiting an ultracool red dwarf inside Milky Way. This planet, tidally locked and likely lacking an atmosphere due to intense radiation, offers new insights into long-lived red dwarfs, which are predicted to be among the last stars to burn out in the universe.

Our galaxy is a treasure trove of red stars. In fact, more than 70% of the stars in the Milky Way are M dwarfs, also known as red dwarfs. These stars are cool and dim compared to our Sun, but they often burst into orbits of high-energy radiating exoplanets, especially early in their lives. And those “lives” last a tall the time. Stars like our Sun burn for about 10 billion years before turning into hungry red giants that devour any nearby planets. M dwarfs continue to burn for 100 billion years or more, possibly providing a basis for life and an even longer window for life to develop.

An international team using robotic telescopes around the world recently discovered an Earth-sized planet orbiting an ultra-cool red dwarf, the faintest and longest-lived stars. When the universe gets cold and dark, these will be the last stars to burn out.

DISCLOSURE

of exoplanets SPECULOOS-3 b is about 55 light years from Earth (really close when you consider the cosmic scale!) and about the same size. A year there, one orbit around the star, takes about 17 hours. However, the days and nights may never end: The planet is thought to be tidally locked, so the same side, known as day, always faces the star, like the Moon on Earth. The night side would close in endless darkness.

An artist’s concept of the exoplanet SPECULOOS-3 b orbiting its red dwarf star. The planet is about the same size as Earth, while its star is slightly larger than Jupiter – but much more massive. Credit: Lionel Garcia

Exploring ultra-cold dwarfs

In our corner of the galaxy, ultracool dwarf stars are ubiquitous. They are so faint that their planetary population is largely unexplored. The SPECULOOS (Search for Planets EClipsing ULtra-COOL Stars) project, led by Michael Gillon at the University of Liège, Belgium, was set up to change this. Ultra-cool dwarf stars are scattered across the sky, so you have to observe them one at a time, for weeks at a time, to have a good chance of detecting transiting planets. For this, you need a dedicated network of professional telescopes. This is the concept of SPECULOOS.

“We designed SPECULOOS specifically to explore nearby ultracool dwarf stars in search of rocky planets,” Gillon said. ”With the SPECULOOS prototype and the decisive help of NASA Spitzer Space Telescope, we discovered the famous TRAPPIST-1 system. It was a great start!”

Gillon is lead author of the paper announcing the planet’s discovery, published on May 15, 2024, in Astronomy of Nature. The project is a truly international effort, in partnership with the Universities of Cambridge, Birmingham, Bern, Massachusetts Institute of Technology and ETH Zürich.

The star SPECULOOS-3 is thousands of degrees cooler than our Sun with an average temperature of about 4,760 F (2,627 C), but it blasts its planet with radiation, meaning it likely has no atmosphere.

Seeing the star, let alone the planet, is a feat in itself. “Although this particular red dwarf is more than a thousand times fainter than the Sun, its planet orbits much, much closer than Earth, heating the planetary surface,” said co-author Catherine Clark, a postdoctoral researcher at the Jet Laboratory NASA Propulsion. in Southern California.

Funny facts

• While the planet is as big as Earth, its star is slightly larger than Jupiter – but much more massive.
• The planet receives almost 16 times more energy per second than the Earth receives from the Sun.
• Got the cookie link? The SPECULOOS planet-finding program shares its name with the spiced sweetbread. Both come from Belgium. Sweet!

Next steps

SPECULOOS-3 b is an excellent candidate for follow-up observations by the James Webb Space Telescope. Not only can we learn about the potential of an atmosphere and surface mineralogy, but it can also help us understand the stellar neighborhood and our place in it.

”We are making great progress in our study of planets orbiting other stars. We have now reached the stage where we can detect and study Earth-sized exoplanets in detail. The next step will be to determine whether any of them are habitable, or even habitable,” said Steve B. Howell, one of the planet’s discoverers at NASA’s Ames Research Center in Silicon Valley.

For more on this discovery:

Reference: “Discovery of an Earth-sized exoplanet orbiting the ultracool dwarf star SPECULOOS-3” by Michaël Gillon, Peter P. Pedersen, Benjamin V. Rackham, Georgina Dransfield, Elsa Ducrot, Khalid Barkaoui, Artem Y. Burdanov , Urs Schroffene , Yilen Gómez Maqueo Chew, Susan M. Lederer, Roi Alonso, Adam J. Burgasser, Steve B. Howell, Norio Narita, Julien de Wit, Brice-Olivier Demory, Didier Queloz, Amaury HMJ Triaud, Laetitia Delrez, Emmanueltehh J. Hooton, Lionel J. Garcia, Clàudia Jano Muñoz, Catriona A. Murray, Francisco J. Pozuelos, Daniel Sebastian, Mathilde Timmermans, Samantha J. Thompson, Sebastián Zúñiga-Fernández, Jesús Aceituno, Christian Agan. Thomas Baycroft, Zouhair Benkhaldoun, David Berardo, Emeline Bolmont, Catherine A. Clark, Yasmin T. Davis, Fatemeh Davoudi, Zoë L. de Beurs, Jerome P. de Leon, Masahiro Ikoma, Kai Ikuta, Keisuke Isogai, Izurukihi Fukuda, Fukui , Roman Gerasimov, Mourad Ghachoui, Maximilian N. Günther, Samantha Hasler, Yuya Hayashi, Kevin Heng, Renyu Hu, Taiki Kagetani, Yugo Kawai, Kiyoe Kawauchi, Daniel Kitzmann, Daniel DB Koll, Monika Lendl, John Xintongving, John H. Lyu , Erik A. Meier Valdés, Mayuko Mori, James J. McCormac, Felipe Murgas, Prajwal Niraula, Enric Pallé, Ilse Plauchu-Frayn, Rafael Rebolo, Laurence Sabin, Yannick Schackey, Nicole Schanche, Franck Selsis, Alfredo Sota, , Matthew R. .Standing, Keivan G. Stassun, Motohide Tamura, Yuka Terada, Christopher A. Theissen, Martin Turbet, Valérie Van Grootel, Roberto Varas, Noriharu Watanabe, and Francis Zong Lang, 15 May 2024, Astronomy of Nature.
DOI: 10.1038/s41550-024-02271-2