{"id":53759,"date":"2026-11-08T18:30:00","date_gmt":"2026-11-08T23:30:00","guid":{"rendered":"https:\/\/www.ecoticias.com\/en\/?p=53759"},"modified":"2026-11-02T12:45:15","modified_gmt":"2026-11-02T17:45:15","slug":"a-dying-star-may-have-built-a-second-generation-planet-out-of-the-gas-it-threw-off-and-the-clue-had-been-hiding-in-hubble-data-since-1999","status":"publish","type":"post","link":"https:\/\/www.ecoticias.com\/en\/a-dying-star-may-have-built-a-second-generation-planet-out-of-the-gas-it-threw-off-and-the-clue-had-been-hiding-in-hubble-data-since-1999\/53759\/","title":{"rendered":"A dying star may have built a second-generation planet out of the gas it threw off, and the clue had been hiding in Hubble data since 1999"},"content":{"rendered":"\n

Astronomers say the white dwarf HS 0209+0832 may be feeding on a second-generation planet. This giant world seems to have formed from gas its own star shed while dying. A team led by the University of Warwick reported the candidate on October 5, 2026, after decoding Hubble data from 1999.<\/p>\n\n\n\n

The study appeared in Nature Astronomy<\/a> with 12 authors. Jamie Williams, a PhD student in Warwick’s Department of Physics, is the first author. If confirmed, the planet would be the first of its kind around a white dwarf.<\/p>\n\n\n\n

A hundred lines nobody could match<\/h2>\n\n\n\n

Hubble pointed its STIS spectrograph at the star on January 10, 1999. The ultraviolet spectrum showed carbon, silicon, nickel and zinc. It also held roughly 100 absorption lines that no one could identify.<\/p>\n\n\n\n

Decades later, Williams went back to those records with an updated chemical database. According to the paper, most of the mystery lines belong to copper and niobium, with 62 lines from niobium alone. Data from NASA’s retired FUSE<\/a> spectrograph, taken in December 2002, carried the same signal.<\/p>\n\n\n\n

\"Hubble
Part of Hubble’s ultraviolet spectrum of HS 0209+0832: the dips labeled niobium, nickel and calcium show where those elements absorb light, with Hubble data in white and the best-fit model in red. (Image: NASA, ESA, Leah Hustak (STScI))<\/figcaption><\/figure>\n\n\n\n

Before this study, astronomers had never detected niobium in a white dwarf. The team checked FUSE spectra of 33 other metal-polluted white dwarfs and found none there. “Once we realized it was there, everything fell into place,” co-author Boris G\u00e4nsicke of Warwick said in the NASA release.<\/p>\n\n\n\n

Metals forged in a red giant<\/h2>\n\n\n\n

White dwarfs are the hot, dense cores left when stars like the sun run out of fuel. Many of them swallow crumbs of old asteroids and planets. That debris is usually rich in silicon and iron, the stuff of rocks.<\/p>\n\n\n\n

Around HS 0209+0832, the pattern runs the other way. Its atmosphere carries extra zinc, copper and niobium but little silicon and iron. Warwick puts the niobium at more than 1,000 times the sun’s level.<\/p>\n\n\n\n

Helium makes up about 1 percent of that atmosphere as well. At a temperature of about 64,000\u00b0F (35,800 kelvin), helium should sink out of sight within months. Its presence means fresh material keeps arriving.<\/p>\n\n\n\n

Nicholas Stone of the University of Wisconsin-Madison links the mix to the s-process, a chain of nuclear reactions inside bloated red giants. “It’s a chemical signature no ordinary, ‘first-generation’ planet should carry,” he said in the Warwick release.<\/p>\n\n\n\n

Earth and its neighbors are first-generation worlds, built from leftovers of the sun’s birth. A second-generation planet grows from material a star ejects at the end of its life. Until now, astronomers had only suspected such worlds around pulsars.<\/p>\n\n\n\n

A 4.4-day flicker in TESS data<\/h2>\n\n\n\n

NASA’s TESS satellite stared at the white dwarf in sectors 42, 43, 70 and 71, about four months in all. In that light curve, the team found a faint brightness wave repeating every 4.399 days. Its amplitude was just 0.120 percent.<\/p>\n\n\n\n

According to the authors, the wave has two possible causes. We may be seeing the planet’s hot day side and cooler night side in turn. Or a comet-like tail of escaping gas may cross our line of sight once per orbit.<\/p>\n\n\n\n

NASA estimates the candidate is a gas giant about the size of Jupiter. It circles at roughly 3.7 million miles (6 million kilometers), far closer than Mercury sits to the sun. At that range, the young star’s heat boils off the top of the planet’s atmosphere, like on other roasting exoplanets<\/a>.<\/p>\n\n\n\n

Some of that gas falls back on the white dwarf, and its helium rules out a rock as the source, the authors write. “If the second-generation planet is there, I think it is likely to survive,” Williams said in the NASA announcement<\/a>.<\/p>\n\n\n\n

A partner star catching debris<\/h2>\n\n\n\n

Building such a planet is hard, which may explain why none had turned up. A lone dying star sheds its envelope fairly evenly in all directions. The gas then drifts away, as in the disintegrating star of the Exposed Skull Nebula<\/a>.<\/p>\n\n\n\n

Williams says HS 0209+0832 “likely required a companion star that pulled the ejected material back into orbit,” according to the University of Warwick<\/a>. In the paper, the team argues that a low-mass partner could have spun up a disk rich in s-process metals.<\/p>\n\n\n\n

From there, a giant planet could have collapsed directly out of that disk. Or an older sub-Neptune or super-Earth wandered into it and picked up a fresh atmosphere around its original core, a messier route the authors also lay out.<\/p>\n\n\n\n

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