Astronomers find seven planets being ‘fried’ – 11/06/2023 – Science

In our Solar System, Mercury is the planet that orbits closest to the Sun, perpetually fried by Solar radiation seven times greater than on Earth.

Astronomers using data obtained from the Kepler space telescope, now retired by NASA, identified seven planets orbiting another star in the Milky Way, each of them suffering from the power of its star and receiving radiant energy even more brutal than that seen on Mercury.

This is the second system with the most planets identified around any star after our Solar System.

All seven planets are larger than Earth, the largest of the four rocky planets in our Solar System, but smaller than Neptune, the smallest of the four gaseous planets around the Sun. They all have orbits closest to their star — called Kepler -385— than Mercury in relation to the Sun.

“All the planets are ‘fried’ more intensely than any other planet in our Solar System,” said astronomer Jack Lissauer of NASA’s Ames Research Center in California. He is the author of the study that will be published in Planetary Science and placed on the arXiv research website.

To date, scientists have identified more than 5,500 exoplanets — as those outside our Solar System are called — and found hundreds of stars with multiple exoplanets. But Kepler-385’s collection of seven is surpassed only by the eight orbiting a star called Kepler-90. Another star, Trappist-1, has seven planets. Our Solar System has eight.

The Kepler space telescope, a member of NASA’s first planet-hunting mission, was retired in 2018. It detected exoplanets by small points passing in front of the brightness of stars when a planet crossed between its point and that star.

The study highlights how different types of solar systems exist, and many likely don’t look like ours. It is almost certain that systems with more than eight planets exist, but telescopes are not yet powerful enough to identify small exoplanets.

The star Kepler-385 is about 10% larger than the diameter and mass of our Sun, and is also slightly more luminous and hot. It is located about 5,000 light years from Earth. A light year corresponds to the distance that light travels in one year, or 9.5 trillion kilometers.

The smallest of the seven planets — which is still 20% larger than Earth — is the one that orbits closest to the star, around 4% of our distance from the Sun. The next planet is about 20% larger than Earth. the one closest to the star.

“Both should be rocky and ‘blocky’, showing the same face to their star all the time, like the Moon does to Earth,” Lissauer said. “This makes them extremely hot at the closest point to the star. Because any atmosphere is likely to have evaporated long ago, their hemispheres facing away from the star are perpetually dark and extremely cold.”