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Scientists report first evidence of a planet formed from a dead star's ashes
Коротко
A study published Monday in Nature Astronomy says a planet may have formed from material expelled by its dying star, which would be the first recorded “second-generation” planet. The likely gas giant orbits a white dwarf called HS 0209+0832 about 270 light-years from Earth, according to the study authors. The evidence includes heavy elements, including niobium, on the white dwarf's surface and a brightness signal repeating every 4.4 days.
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Scientists say they have detected a planet that may have formed from the burned remains of its dead host star, a result the study authors describe as a first. The study, published Monday in the journal Nature Astronomy, says the planet is likely a gas giant orbiting a white dwarf called HS 0209+0832 about 270 light-years from Earth. [ 1 , 2 ]
The team found unusual traces of heavy elements on the white dwarf's surface, which the authors believe is planetary material raining down onto the leftover core. Lead study author Jamie Williams, a doctoral student in the department of physics at the University of Warwick in England, said the material is “very rich in an element called niobium” — the first time that element has been found in a white dwarf — which implies the planetary material is made from the ashes of the star as it died. [ 1 , 2 ]
The researchers analyzed observations from NASA's Hubble Space Telescope and other instruments. Analysis of NASA's Transiting Exoplanet Survey Satellite, or TESS, revealed a faint brightness signal repeating every 4.4 days, which the researchers say is evidence consistent with a giant planet orbiting the white dwarf. [ 1 , 2 ]
When a sunlike star dies, it first expands into a red giant and then sheds its outer layers, leaving behind a much smaller but dense, hot core known as a white dwarf. Some first-generation planets — those that formed at the same time as the star — can survive that event if their orbit is wide enough. Astronomers have observed a handful of such survivors around white dwarfs, but the documents say no second-generation planet, built from a dead star's debris, had been recorded before. [ 1 , 2 ]
Williams also said that because white dwarfs cool over time, planets orbiting close to them have a very stable habitable zone, and a second-generation planet could form and then be in that zone. The documents do not state that this planet is in such a zone. [ 2 ]
Reuters also covered the finding, describing the object in its headline as an alien “phoenix planet” born from the ashes of a dying star. Its feed summary carried no further details. [ 3 ]
Почему это важно
Astronomers have previously found only planets that formed alongside their star and survived its death; a world built from a dead star's debris would be a new class of planet. The documents quote the lead author saying that because white dwarfs cool over time, a planet close to one could sit in a stable habitable zone, though no claim is made that this planet is habitable.
Ключевые факты
- A study published Monday in the journal Nature Astronomy reports a planet that may have formed from the remains of its dead host star. [ 1 , 2 ]
- The planet is likely a gas giant orbiting a white dwarf called HS 0209+0832 about 270 light-years from Earth. [ 1 , 2 ]
- The authors say it would be the first recorded “second-generation” planet, made from a dead star's debris. [ 1 , 2 ]
- The white dwarf's surface shows unusual traces of heavy elements, including niobium, which the authors interpret as planetary material raining down onto the core. [ 1 , 2 ]
- Analysis of NASA's Transiting Exoplanet Survey Satellite observations revealed a faint brightness signal repeating every 4.4 days, which the researchers say is consistent with a giant planet orbiting the white dwarf. [ 1 ]
- Lead study author Jamie Williams is a doctoral student in the department of physics at the University of Warwick in England. [ 1 , 2 ]
- Astronomers have observed a handful of first-generation planets that survived a star's death around white dwarfs, but no second-generation planet before this. [ 1 , 2 ]
Подтверждено несколькими источниками
- A study published Monday in the journal Nature Astronomy reports a planet likely to be a gas giant orbiting a white dwarf about 270 light-years from Earth. [ 1 , 2 ]
- Lead study author Jamie Williams is a doctoral student in the department of physics at the University of Warwick in England. [ 1 , 2 ]
- The white dwarf's surface shows unusual traces of heavy elements, and the study authors believe this is planetary material raining down onto the leftover core. [ 1 , 2 ]
- The researchers analyzed observations from NASA's Hubble Space Telescope and other instruments, as well as NASA's Transiting Exoplanet Survey Satellite. [ 1 , 2 ]
- The authors describe the object as a possible first recorded second-generation planet, made from material ejected by the star during its giant phase. [ 1 , 2 ]
Пока неясно
- Whether the planet is confirmed or still a candidate. Both documents say the planet “may” or “could” have formed this way, and the evidence described is indirect: chemical traces and a repeating brightness signal rather than direct imaging.
- The planet's designation, mass and size. Neither document names or measures the planet.
- Whether the planet could remain in a habitable zone, and for how long. This is attributed to a single source, UPI, quoting lead author Jamie Williams, and the quotation is truncated in the document.