Like a golf ball circling a hole, the planet Kepler-1658b is getting closer and closer to falling into its star, that is.
Scientists observing the exoplanet having noticed its orbital period around its mature or “evolved” parent Star decreases over time, indicating that the planets are approaching a fatal collision with its star.
“We have detected evidence of exoplanets inspiring towards their stars before, but we have never seen such a planet around an evolved star,” said Shreyas Vissapragada, exoplanet scientist at the Harvard and Smithsonian Center for Astrophysics and co- author of a new study on the sightings, says in a statement (opens in a new tab).
It is quite difficult to determine the orbital decay of exoplanets. The process is quite slow, as astronomers have to wait to see many transits of an exoplanet in front of its star. When a planet transits its star, the star appears to darken from the perspective of Earth; astronomers observing repeated transits can follow this gradation to reconstruct the distant planet’s activities, including its orbital period. Fortunately for Vissapragada and his colleagues, Kepler-1658b has an incredibly short orbital period of 3.8 days, so transits occur frequently.
Kepler-1658b is considered a “Hot Jupiter“, or an exoplanet with a mass and size similar to Jupiter, but a much hotter temperature due to its proximity to its star. It was first spotted by retired NASA exoplanet hunter Kepler Space Telescope in 2009, but has not been confirmed as an exoplanet until 2019.
Yet scientists have continuously observed the exoplanet since Kepler spotted it, first using Kepler and then the Palomar’ Observatorys Hale Telescope in California, then NASA’s Transiting Exoplanet Survey Telescope (TESS) launched in 2018 to continue the search for distant planets. During these 13 years, the trio of instruments recorded a constant decrease in the orbital period of Kepler-1658b: 131 milliseconds per year.
Vissapragada and his colleagues now theorize that the orbital decay is caused by tidal interactions between the exoplanet and its star – the same type of interaction that affects the relationship between Earth and the planet. moon. In our case, however, the Earth and the Moon become further apart due to tidal interactions. In the case of Kepler-1658b, the exoplanet is approaching its star.
“Now that we have evidence of planet inspiration around an evolved star, we can really start refining our tidal physics models,” Vissapragada said. “The Kepler-1658 system can serve as a celestial laboratory in this way for years to come, and hopefully there will soon be many more such laboratories.”
The research is described in a paper published Monday, December 19 in Astrophysical Journal Letters.