{"id":18716,"date":"2026-10-06T11:03:07","date_gmt":"2026-10-06T09:03:07","guid":{"rendered":"https:\/\/deep-space-astronomy.ch\/?p=18716"},"modified":"2026-10-06T11:03:07","modified_gmt":"2026-10-06T09:03:07","slug":"hubble-naine-blanche-planete-seconde-generation-5-octobre-2026","status":"publish","type":"post","link":"https:\/\/deep-space-astronomy.ch\/en\/hubble-naine-blanche-planete-seconde-generation-5-octobre-2026\/","title":{"rendered":"Hubble Discovers a Second-Generation Planet Orbiting a White Dwarf: A Dead Star Gives Birth to a World (October 5, 2026)"},"content":{"rendered":"

On October 5, 2026, a team led by Jamie Williams (a doctoral student at the University of Warwick) published a paper in *Nature Astronomy* reporting the discovery of a planet that is believed to have formed not at the same time as its star, but after the star\u2019s death. Orbiting the white dwarf HS 0209+0832, located about 270 light-years away, the Hubble Space Telescope detected unusual amounts of niobium, a heavy element that does not form in the cores of stars but rather during the final convulsions of their death throes. This is the first candidate for a second-generation planet.<\/p>\n

What is a white dwarf?<\/h2>\n
\"Concept
Artist's concept of the HS 0209+0832 system: a white dwarf surrounded by a disk of ejected material, with a second-generation planet in orbit. Credit: ESA\/Hubble & NASA. Public domain. Hubble detected niobium in the spectrum of this white dwarf, a signature of a planet born from the star\u2019s ashes.<\/figcaption><\/figure>\n

A white dwarf is the compact remnant of a low-mass star (such as the Sun) that has burned through all its nuclear fuel. The star goes through a red giant phase: it swells, ejects its outer layers into space, and leaves behind only a dense core the size of a planet, composed of carbon and oxygen. This is a white dwarf.<\/p>\n

In about 5 billion years, the Sun will become a white dwarf. Earth will likely be swallowed up by the Sun as it becomes a red giant, or vaporized. But the outer planets, such as Jupiter, might survive. And new planets could form from the material ejected by the dying star.<\/p>\n

A Planet Born from the Ashes<\/h2>\n

The planets of the Solar System are first-generation: they formed from the disk of gas and dust that surrounded the young Sun, at the same time as the Sun itself. A second-generation planet would form after the star\u2019s death, from material ejected during the red giant phase.<\/p>\n

This is what Hubble detected around HS 0209+0832. The white dwarf exhibits unusual chemical abundances: high levels of niobium, zinc, and copper (so-called trans-fer elements), but low levels of silicon and iron (the classic rocky elements). Niobium is overrepresented by a factor of 1,000 compared to the Sun.<\/p>\n

Niobium is an element heavier than iron. However, elements heavier than iron are not formed by thermonuclear fusion in the cores of stars. They are synthesized under the extreme conditions that arise briefly in dying stars, particularly during the asymptotic giant branch (AGB) phase. Niobium is a hallmark of these \u00abdeath throes.\u00bb.<\/p>\n

The Plot<\/h2>\n

The Williams team proposes the following scenario:<\/p>\n

    \n
  1. The star, with a mass comparable to that of the Sun, is nearing the end of its life and entering the AGB phase. It ejects its outer layers, which are enriched with heavy elements synthesized during the AGB phase.<\/li>\n
  2. A fraction of this ejected material remains around the white dwarf and forms a circumstellar disk.<\/li>\n
  3. In this disk, a giant gas planet is forming from second-generation material enriched in niobium and other elements produced by the s-process (slow neutron capture).<\/li>\n
  4. The white dwarf, still very hot, bombards the planet with radiation. The planet loses part of its atmosphere, which falls back onto the white dwarf. This is what allows Hubble to detect the signatures of niobium in the star\u2019s spectrum.<\/li>\n<\/ol>\n

    The candidate planet is a gas giant about the size of Jupiter, orbiting about 6 million kilometers from the white dwarf\u2014much closer than Mercury is to the Sun. TESS observed periodic variations in the white dwarf\u2019s brightness over a four-month period, confirming the presence of an orbiting body.<\/p>\n

    A \u00abcold case\u00bb solved<\/h2>\n

    Hubble first observed HS 0209+0832 in 1999. The data contained about 100 unidentified spectral features. For more than 25 years, these signatures remained in the archives, unexplained.<\/p>\n

    Jamie Williams revisited these archives using an updated chemical database and discovered that niobium matched many of the mysterious characteristics. Niobium had never been detected in any other white dwarf analyzed to date.<\/p>\n

    The team confirmed Hubble's observations with data from FUSE (Far Ultraviolet Spectroscopic Explorer, NASA), which also revealed signs of niobium in the system. TESS (Transiting Exoplanet Survey Satellite, NASA) provided the transit detection of the planet.<\/p>\n

    \u00abWhen Jamie told me about niobium in this study, I was truly astonished, because this element had never been reported in any other white dwarf analyzed to date,\u00bb said Boris Gaensicke, a co-author of the study at the University of Warwick.<\/p>\n

    Life After Death<\/h2>\n

    The discovery suggests that stars may have a \u00absecond act.\u00bb After a star dies and a white dwarf forms, new planets could form from the ejected material. These second-generation planets would have a chemical composition distinct from that of first-generation planets: enriched in s-process elements, such as niobium, and depleted in classic rocky elements.<\/p>\n

    \u00abRather than the white dwarf phase being a sort of epilogue to the story of a star and its planets, this research suggests that the systems we know of are only the first chapter of a potentially much longer tale, with new characters appearing,\u00bb said Jamie Williams.<\/p>\n

    The candidate planet is currently losing its atmosphere as it is bombarded by radiation from the still-very-hot white dwarf. But Williams believes it will survive. Once the white dwarf has cooled, the planet will be in a stable habitable zone for millions of years.<\/p>\n

    Why It's Important to Us<\/h2>\n

    The Sun will become a white dwarf. If a second-generation planet can form around a white dwarf, it means that the fate of the Solar System does not end with the Sun\u2019s death. Heavy elements synthesized during the AGB phase, such as niobium, could form new worlds around our dying star.<\/p>\n

    The research also opens up a new field: the search for second-generation planets orbiting white dwarfs. Hubble, JWST, and future instruments such as PRIMA (scheduled for launch in 2033) will be able to search for other similar systems. The white dwarf HS 0209+0832 is 270 light-years away, too far for an amateur telescope to see, but its story tells us about our own stellar future.<\/p>\n

    Sources : ESA\/Hubble \u2013 Suspected Second-Generation Planet Solves Hubble Cold Case (Oct. 5, 2026)<\/a> ; Nature Astronomy \u2013 Discovery of a second-generation planet candidate (Oct. 5, 2026)<\/a> ; NASA\/Hubble \u2013 Suspected Second-Generation Planet Solves NASA Hubble Cold Case<\/a><\/em><\/p>\n

    See also on Deep Space Astronomy: PRIMA: NASA Selects Its Next Major Space Telescope to Explore the Cold Universe (2026)<\/a> ; JWST Detects Water and Dust Near the Milky Way's Central Black Hole<\/a><\/em><\/p>\n

    Signature: CBurkhalter<\/em><\/p>\n<\/div><\/div>","protected":false},"excerpt":{"rendered":"

    Le t\u00e9lescope Hubble a d\u00e9tect\u00e9 du niobium autour de la naine blanche HS 0209+0832, \u00e0 270 ann\u00e9es-lumi\u00e8re. Premi\u00e8re candidate d’une plan\u00e8te de seconde g\u00e9n\u00e9ration, n\u00e9e du mat\u00e9riel expuls\u00e9 par l’\u00e9toile mourante. Vulgarisation : naine blanche, processus s, niobium, affaire froide r\u00e9solue apr\u00e8s 25 ans dans les archives Hubble.<\/p>","protected":false},"author":187,"featured_media":18715,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[827],"tags":[],"class_list":["post-18716","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-actualites"],"_links":{"self":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/posts\/18716","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/users\/187"}],"replies":[{"embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/comments?post=18716"}],"version-history":[{"count":1,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/posts\/18716\/revisions"}],"predecessor-version":[{"id":18717,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/posts\/18716\/revisions\/18717"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/media\/18715"}],"wp:attachment":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/media?parent=18716"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/categories?post=18716"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/tags?post=18716"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}