Young gas giants I thought planets were big and low density, but gas giants around stars only 20 million years ago do not fit this model
December 2, 2021
Like two jupiters planet Its orbit is much smaller than expected for young stars, so it may be necessary to reconsider our thoughts on the early evolution of gas giants.
Our current understanding of the evolution of Jupiter-type planets predicts that these worlds will begin as large, low-density objects. “We expect them to look like very large, fluffy spheres of gas,” he says. Alejandro Suarez Mascarenho At the Institute of Astrophysics in the Canary Islands of Spain.
Over the next hundreds of millions of years, the planets are expected to slowly contract until they are about the size of Jupiter and Saturn in our solar system. However, these predictions have not been tested so far because it is difficult to monitor the infant planetary system.
A young star, known as V1298 Tau, only 20 million years ago, gave astronomers a rare window to the formation of gas giants. Early 2010s, Kepler Space Telescope We observed that V1298 Tau was orbited by four gas giants. Suárez Mascareño and his colleagues followed up on the discovery by monitoring the stars and their planets between April 2019 and April 2020.
Of the four planets, researchers have discovered that the two outermost planets (V1298 Taub and V1298 Taue) have unexpected features. They are about 0.64 and 1.16 times the mass of Jupiter, respectively, but have radii 0.868 and 0.735 times the mass of Jupiter, respectively. This means that the two planets are much smaller and denser than the researchers expected. This suggests that it contracted faster than the current idea suggests.
It is unclear whether these features are normal or strange, as this is one of the first detailed studies of such a young planetary system, says Suárez Mascareño. Our understanding of the evolution of Jupiter planets may be wrong. Alternatively, the planet could be an anomalous gas giant with an unusually huge core, which would accelerate the contraction process.
“Our understanding of the evolution of planets and the early stages of the evolution of the planetary system may actually be very limited,” says Suárez Mascareño. “Currently, this case is inconsistent with our previous knowledge. But it is one case. It cannot be generalized from one case.”
Suárez Mascareño hopes to shed light on the formation of our own solar system by collecting more data on more infant planetary systems.
Journal reference: Nature Astronomy, DOI: 10.1038 / s41550-021-01533-7
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