Topic: Space
Astronomers discovered a new planetary system where a rocky planet orbits far from its star. This challenges our current understanding of how planets form.
A team of international astronomers found a surprising pattern in a distant planetary system. In most systems, small rocky planets orbit close to their star, while large gas giants orbit farther away. Our own Solar System follows this rule. The inner planets are made mostly of rock and metal, while the outer planets have thick atmospheres made of gas. This arrangement is explained by our current theory of planet formation. Young stars emit intense radiation that can strip away gases from nearby developing planets, leaving behind solid, rocky worlds. Farther from the star, cooler temperatures allow planets to hold onto thick atmospheres, leading to the formation of gas giants.
The team studied a system orbiting a small, cool red dwarf star called LHS 1903. They initially found three planets: one rocky and two gas-rich. But further observations revealed a fourth planet, LHS 1903 e, orbiting farthest from the star. This new planet is also rocky.
The team explored several possible explanations for this unusual pattern. They considered whether a massive impact might have stripped away the planet's atmosphere or if the planets could have shifted positions over time. Detailed computer simulations and studies of the planets' orbits ruled out both scenarios.
Instead, the findings point to a more unexpected idea: the planets in this system may not have formed simultaneously. Rather, they could have developed one after another as conditions around the star changed.
This challenges our current understanding of planet formation. Instead of forming within a protoplanetary disc, planets might take shape sequentially in shifting environments. The local conditions at the time each planet finishes forming determine whether it becomes gas-rich or remains rocky.
Why It Matters
Understanding how planets form can help us better understand the universe and potentially lead to new discoveries about life beyond Earth.
Key Facts
- Astronomers discovered a planetary system where a rocky planet orbits far from its star, challenging our current understanding of planet formation.
- The system orbiting LHS 1903 has four planets: one rocky and three gas-rich.
- Further observations revealed that the fourth planet is also rocky, unlike expected.
- The team explored several possible explanations for this unusual pattern, ruling out massive impacts and planetary shifts.
- The findings suggest that the planets in this system may not have formed simultaneously, but rather developed sequentially.
Key Terms
- Protoplanetary disc
- A swirling cloud of gas and dust surrounding a young star where planets form.
Implications
Understanding how planets form can help us better understand the universe and potentially lead to new discoveries about life beyond Earth.
Source: https://www.sciencedaily.com/releases/2026/02/260213223857.htm
Journal Reference:
- Thomas G. Wilson, Anna M. Simpson, Andrew Collier Cameron, Ryan Cloutier, Vardan Adibekyan, Ancy Anna John, Yann Alibert, Manu Stalport, Jo Ann Egger, Andrea Bonfanti, Nicolas Billot, Pascal Guterman, Pierre F. L. Maxted, Attila E. Simon, Sérgio G. Sousa, Malcolm Fridlund, Mathias Beck, Anja Bekkelien, Sébastien Salmon, Valérie Van Grootel, Luca Fossati, Alexander James Mustill, Hugh P. Osborn, Tiziano Zingales, Matthew J. Hooton, Laura Affer, Suzanne Aigrain, Roi Alonso, Guillem Anglada, Alexandros Antoniadis-Karnavas, Tamas Bárczy, David Barrado Navascues, Susana C. C. Barros, Wolfgang Baumjohann, Thomas Beck, Willy Benz, Federico Biondi, Xavier Bonfils, Luca Borsato, Alexis Brandeker, Christopher Broeg, Lars A. Buchhave, Maximilian Buder, Juan Cabrera, Sebastian Carrazco Gaxiola, David Charbonneau, Sébastien Charnoz, David R. Ciardi, Karen A. Collins, Kevin I. Collins, Rosario Cosentino, Szilard Csizmadia, Patricio E. Cubillos, Shweta Dalal, Mario Damasso, James R. A. Davenport, Melvyn B. Davies, Magali Deleuil, Laetitia Delrez, Olivier D. S. Demangeon, Brice-Olivier Demory, Victoria DiTomasso, Diana Dragomir, Courtney D. Dressing, Xavier Dumusque, David Ehrenreich, Anders Erikson, Emma Esparza-Borges, Andrea Fortier, Izuru Fukuda, Akihiko Fukui, Davide Gandolfi, Adriano Ghedina, Steven Giacalone, Holden Gill, Michaël Gillon, Yilen Gómez Maqueo Chew, Manuel Güdel, Pere Guerra, Maximilian N. Günther, Nathan Hara, Avet Harutyunyan, Yuya Hayashi, Raphaëlle D. Haywood, Rae Holcomb, Keith Horne, Sergio Hoyer, Chelsea X. Huang, Masahiro Ikoma, Kate G. Isaak, James A. G. Jackman, Jon M. Jenkins, Eric L. N. Jensen, Daniel Jontof-Hutter, Yugo Kawai, Laszlo L. Kiss, Ben S. Lakeland, Jacques Laskar, David W. Latham, Alain Lecavelier des Etangs, Adrien Leleu, Monika Lendl, Jerome de Leon, Florian Lienhard, Mercedes López-Morales, Christophe Lovis, Michael B. Lund, Rafael Luque, Demetrio Magrin, Luca Malavolta, Aldo F. Martínez Fiorenzano, Andrew W. Mayo, Michel Mayor, Christoph Mordasini, Annelies Mortier, Felipe Murgas, Norio Narita, Valerio Nascimbeni, Belinda A. Nicholson, Göran Olofsson, Roland Ottensamer, Isabella Pagano, Larissa Palethorpe, Enric Pallé, Hannu Parviainen, Marco Pedani, Francesco A. Pepe, Gisbert Peter, Matteo Pinamonti, Giampaolo Piotto, Don Pollacco, Ennio Poretti, Didier Queloz, Samuel N. Quinn, Roberto Ragazzoni, Nicola Rando, David Rapetti, Francesco Ratti, Heike Rauer, Federica Rescigno, Ignasi Ribas, Ken Rice, George R. Ricker, Paul Robertson, Thierry de Roche, Laurence Sabin, Nuno C. Santos, Dimitar D. Sasselov, Arjun B. Savel, Gaetano Scandariato, Nicole Schanche, Urs Schroffenegger, Richard P. Schwarz, Sara Seager, Ramotholo Sefako, Damien Ségransan, Avi Shporer, André M. Silva, Alexis M. S. Smith, Alessandro Sozzetti, Manfred Steller, Gyula M. Szabó, Motohide Tamura, Nicolas Thomas, Amy Tuson, Stéphane Udry, Andrew Vanderburg, Roland K. Vanderspek, Julia Venturini, Francesco Verrecchia, Nicholas A. Walton, Christopher A. Watson, Robert D. Wells, Joshua N. Winn, Roberto Zambelli, Carl Ziegler. Gas-depleted planet formation occurred in the four-planet system around the red dwarf LHS 1903. Science, 2026; DOI: 10.1126/science.adl2348
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