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It does so at an enormous rate, taking only 1.4 Earth days to orbit the remnants of a previous star. The gaseous planet is about the size of Jupiter, about 14 times its mass, and orbits the much smaller white dwarf, “WD 1856 + 534,” which is located in the constellation of dragons in the northern sky, about 80 light years from Earth. .
The year before, researchers reported the “first planet to orbit a white dwarf.” In this case, however, due to its proximity to the burned-out star, parts of its atmosphere dissolved and a gas disk formed. A team led by Andrew Vanderburg of the University of Wisconsin and Austrian astrophysicist Lisa Kaltenegger, director of the Carl Sagan Institute at Cornell University in the United States, have now observed the first giant planet that has remained completely in the orbit of a white dwarf. .
Are there other planets?
Using data from NASA’s TESS space telescope, among other things, the researchers discovered the giant planet. It is not yet clear how it entered orbit around the white dwarf, they write in the journal “Nature.”
Simulations of the processes give at least some theoretical answers: In order not to be destroyed when its star expanded into a red giant, the planet must have been more than one astronomical unit (the distance between the earth and the sun) from he. Its original orbit could have changed, possibly influenced by the gravity of several other planets that also survived the death of the stars, as indicated in a companion article to “Nature”, but this is only speculation so far. Over a period of six billion years, this is how old the system is, the planet could have moved closer to the white dwarf and the scenario we are now observing could have emerged.
Effects on the search for life
The fact that a planet survived the death of its star could not only apply to giant planets, but also to smaller rocky planets and possible life on them, and that means promising future work for astronomers. “Now we can look for other smaller planets around stellar cores,” says Vanderburg. If these are Earth-like, that is, rocky planets with liquid water on the surface that can harbor life, traces of this life could be detected with the help of NASA’s James Webb Space Telescope and ESA, writes Lisa Kaltenegger in other: Work published in Astrophysical Journal Letters.
She and her team have developed models and tools to detect signs of life in the atmosphere of planets. With the Webb telescope, which will be launched into space in October 2021, “the strong atmospheric signals that an Earth-like planet would generate if it passed in front of a white dwarf could be recorded, and signs of life could be detected, if any. . Kaltenegger said.
Is it possible to live without sun?
Specifically, the water and carbon dioxide in the atmosphere of said exoplanet could be detected with the space telescope in a few hours. In two days of observation, bio-signatures such as ozone in combination with methane could be recorded. The TESS space telescope, of which Kaltenegger is a member, will now be used to search for rocky planets orbiting white dwarfs.
For the astrophysicist, the discovery raises interesting questions: “What if the death of a star does not mean the end of life on the planets around this star? Could life go on even if our sun goes out? “Signs of life on white dwarf planets” would show not only the incredible tenacity of life, but perhaps also a glimpse into our future, “said Kaltenegger. However, the earth is unlikely to survive the death of the sun for about five billion years.
