In our solar system, tiny rocky Mercury is the planet orbiting closest to the sun, constantly baked by solar radiation seven times more intense than what we experience on Earth.
Using data obtained by NASA’s now retired Kepler Space Telescope, astronomers have identified seven planets orbiting a star in our Milky Way Galaxy, with each suffering the wrath of their star – radiant energy – even more severely than Mercury. These are the second most planets discovered so far around any star outside our solar system.
All seven are larger than Earth, the largest of the four rocky planets in our solar system, but smaller than Neptune, the smallest of the four gas planets in our solar system. They all have orbits closer to their star, called Kepler-385, than Mercury’s average distance from the Sun.
“All planets are being ‘fried’ more intensely than any planet in our solar system,” says astronomer Jack Lissauer of NASA’s Ames Research Center in California, lead author of the study to be published in the Journal of Planetary Science and currently being posted. on the arXiv research site.
Scientists have so far identified more than 5,500 exoplanets – planets outside our solar system – and discovered hundreds of stars with multiple exoplanets. But Kepler-385’s collection of seven exoplanets is led only by the eight known to orbit the star Kepler-90. Another star, TRAPPIST-1, is known to have seven. Our solar system has eight planets.
The Kepler Space Telescope, NASA’s first planet-hunting mission, was decommissioned in 2018. He detected exoplanets by observing small dips in a star’s brightness when a planet passes in front of it from our vantage point.
The new study catalogs about 4,400 planets spotted by the telescope from its launch in 2009 until its retirement. Scientists continue to analyze the data, as evidenced by the identification of Kepler-385’s exoplanet population.
The study further illustrates that there are many different types of planetary systems – and many of them probably don’t look much like our solar system. There are almost certainly planet systems with more than eight, but telescopes have not yet been sensitive enough to properly detect smaller exoplanets.
The star Kepler-385 is about 10% larger in diameter and mass than our Sun, but is slightly brighter and slightly hotter. It is located about 5,000 light-years from Earth. A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).
The smallest of its seven planets – 20% larger than Earth – orbits closest to the star, at a distance of just over 4% of the distance between our planet and the Sun. The next planet is about 20% larger than the innermost planet.
“It’s likely that they are both rocky and tidally locked, causing them to continually show the same face to their star, as the moon does to Earth,” Lissauer said. ‘This makes them especially hot near the point closest to the star. But since any atmosphere has probably boiled away long ago, their away-from-star hemispheres are perpetually dark and extremely cold.”
Most other planets are about 2.4 times larger than Earth.
“They probably all have thick atmospheres and are hot all over their surfaces, which could be well below their cloud tops,” Lissauer said. “The outer planet orbits at about 40% of the Earth-Sun distance. The distance is slightly smaller than the average distance between the Sun and Mercury.”
In the search for life beyond Earth, these planets are not promising candidates.
“The chance of life on any of these seven planets is indeed quite small,” Lissauer said. ‘There may be other planets orbiting further from the star that we don’t know about because they are harder to detect. I didn’t discover it.”
(Except for the headline, this story has not been edited by DailyExpertNews staff and is published from a syndicated feed.)