![]() (Image credit: NASA/JPL-Caltech) (opens in new tab) ![]() NASA’s Spitzer spacecraft (opens in new tab) revealed that at least 1 to 3 percent of white dwarf stars have contaminated atmospheres that suggest rocky material has fallen into them.Īrtists illustration showing a white dwarf stealing material from nearby companion. When a star swells up to become a red giant, it engulfs its closest planets. Those conditions mean that, after shedding much of its mass during the red giant phase, no white dwarf can exceed 1.4 times the mass of the sun (opens in new tab). The more mass, the greater the pull inward, so a more massive white dwarf has a smaller radius than its less massive counterpart. White dwarfs reach this incredible density because they are collapsed so tightly that their electrons are smashed together, forming what is called "degenerate matter." The former stars will keep collapsing until the electrons themselves provide enough of an outward-pressing force to halt the crunch. Sagristà, Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Germany) (opens in new tab) That means a 150-pound (68-kilogram) person on Earth would weigh 50 million pounds (22.7 million kg) on the surface of a white dwarf.Īn all-sky view of some 230,000 white dwarfs discovered with the European Space Agency’s Gaia satellite. According to NASA, the gravity on the surface of a white dwarf is 350,000 times that of gravity on Earth. This makes them among the densest objects in space, beaten out only by neutron stars and black holes. White dwarfs contain approximately the mass of the sun but have roughly the radius of Earth, according to Cosmos (opens in new tab), the astronomy encyclopedia from Swinburne University in Australia. When a star runs out of fuel, it no longer experiences an outward push from the process of fusion and it collapses inward on itself. However, red dwarfs take trillions of years to consume their fuel, far longer than the 13.8-billion-year-old age of the universe, so no red dwarfs have yet become white dwarfs. They simply burn through all of their hydrogen, ending the process as a dim white dwarf. Smaller stars, such as red dwarfs, don't make it to the red giant state. Acknowledgements: Luca Limatola, Budeanu Cosmin Mirel) (opens in new tab) The planetary nebula NGC 2452 is located in the southern constellation of Puppis. The cool, dim star at the center of the blue haze cloud is a white dwarf.
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