Kepler-1658b is a hot-Jupiter exoplanet orbiting a very massive star 2,600 light-years away.
An artist’s concept of the Kepler-1658 system. Image credit: Gabriel Perez Diaz / Instituto de Astrofísica de Canarias.
Kepler-1658 is located approximately 2,600 light-years away in the constellation of Cygnus.
Also known as KOI-4, TYC 3135-652-1, KIC 3861595 and TIC 377873569, the star is 1.45 times more massive and three times larger than the Sun.
While it is younger than our home star, having more mass means it has burned through its hydrogen fuel faster and is already expanding towards becoming a red giant.
Kepler-1658 hosts at least one planet — the hot-Jupiter Kepler-1658b.
This alien world is about 1.1 times the size of Jupiter and 5.7 times as massive.
First detected in 2009 and confirmed 10 years later, it orbits the star once every 3.85 days.
“We’ve previously detected evidence for exoplanets inspiraling toward their stars, but we have never before seen such a planet around an evolved star,” said Dr. Shreyas Vissapragada, a planetary astrophysicist at the Harvard & Smithsonian’s Center for Astrophysics.
“Theory predicts that evolved stars are very effective at sapping energy from their planets’ orbits, and now we can test those theories with observations.”
Measuring the orbital decay of exoplanets has challenged astronomers because the process is very slow and gradual.
In the case of Kepler-1658b, its orbital period is decreasing at the miniscule rate of about 131 milliseconds per year, with a shorter orbit indicating the planet has moved closer to its star.
The root cause of this orbital decay is tides — the same phenomenon responsible for the daily rise and fall in Earth’s oceans.
Tides are generated by gravitational interactions between two orbiting bodies, such as between our world and the Moon or Kepler-1658b and its star.
“The tidal interactions shrinking the planet’s orbit may also be cranking out extra energy within the planet itself,” the researchers said.
They point to a similar situation with Jupiter’s moon Io, the most volcanic body in the Solar System.
“The gravitational push-and-pull from Jupiter on Io melts the planet’s innards,” they said.
“This molten rock then erupts out onto the moon’s famously infernal, pizza-like surface of yellow sulfurous deposits and fresh red lava.”
Stacking additional observations of Kepler-1658b should shed more light on celestial body interactions.
“Now that we have evidence of inspiraling of a planet around an evolved star, we can really start to refine our models of tidal physics,” Dr. Vissapragada said.
“The Kepler-1658 system can serve as a celestial laboratory in this way for years to come, and with any luck, there will soon be many more of these labs.”
A paper on the findings will be published in the Astrophysical Journal Letters.
Source link: https://www.sci.news/astronomy/spiraling-kepler-1658b-11487.html
