Hubble Space Telescope may have found a planet born after its star died

A strange chemical signature in old Hubble observations may point to a planet that formed after its star had already died. Astronomers found unusually high levels of niobium around the white dwarf HS 0209+0832, suggesting some of the star’s expelled material may have assembled into a new gas giant. TESS data also hints at a Jupiter-sized planet orbiting just 3.7 million miles from the star.

Hubble Space Telescope may have found a planet born after its star died. 5 in Nature Astronomy, an unusual chemical signature suggests that the white dwarf HS 0209+0832 could be home to a second-generation planet. A white dwarf is the leftover core of a low-mass star that has exhausted its nuclear fuel and shed its outer layers of gas and dust into space.

Unlike ordinary planets, which form alongside young stars, a second-generation planet takes shape later from material released by a dying star. "Rather than the white dwarf stage being a kind of epilogue to the story of a star and its planets, this research points to the systems we are familiar with only being the first chapter of a potentially much longer tale, with some new characters showing up. That’s a really exciting prospect to pursue," said Jamie Williams, astronomer and lead author, a doctoral candidate at the University of Warwick in the United Kingdom.