Scientists have found evidence suggesting a white dwarf star hosts a second-generation planet, a discovery that would be a first if confirmed. The white dwarf, codenamed HS 0209+0832, was observed by NASA's Hubble telescope in 1999, which recorded 100 chemical features that could not be identified at the time.
A team of scientists led by astronomers from the University of Warwick has now published a paper in Nature. Lead author Jamie Williams found the planet's evidence by comparing Hubble's decades-old observations with an updated chemical database. The unidentified features matched niobium, an element that can only be synthesized in the exotic conditions inside dying stars. Niobium levels in the system were 1,000 times higher than in our sun, pointing to a planet formed from the dying star's materials.
A white dwarf is the dense core left behind after a star like our sun exhausts its nuclear fuel and sheds its outer layers. Unlike the first-generation planets in our solar system, which formed from materials present at the sun's birth, second-generation planets form from material a dying star casts off. Such planets are very rare and were mostly suspected to exist around pulsars, the highly magnetic, rapidly spinning remnants of dead neutron stars. Williams said finding one around a white dwarf, which are more common than pulsars, "was completely unexpected."
The researchers note that the white dwarf is still extremely hot and continues to blast the planet with enough heat to strip away its outer layers. Even so, they believe the planet will endure and remain within the white dwarf's habitable zone for millions of years. The European Research Council, which funded the study, noted that HS 0209+0832 would be the first white dwarf confirmed to host a second-generation planet if the findings hold up.
Source: Engadget · Summarized by HeadlinesBriefing