Fresh Evidence Found in Old Hubble Data / What Is a Second-Generation Planet and How Does It Form?

A reexamination of space observatory data has revealed signs of a possible unknown planet orbiting a white dwarf.

By re-examining Hubble Space Telescope data recorded in 1999, researchers at the University of Warwick have found signs of a possible planet around a white dwarf known as HS 0209+0832. A white dwarf is the dense core left over from a star that has exhausted its fuel and ejected its outer layers into space. The planets of the solar system, including Earth, are formed from material left over from the birth of the Sun; But second-generation planets can be born from material that a star throws into space at the end of its life. Such planets are very rare and previously, their existence was mostly suggested around neutron stars.

Chemical clue in old Hubble data

The story began with about 100 unknown chemical signatures in old Hubble data. Using newer databases, astronomers found that many of these signs correspond to the element niobium; A heavy element produced under special conditions at the end of a star's life. The unusual abundance of this element and other chemical properties suggest that the material that the white dwarf is now absorbing may have formed from a planet formed from the remnants of the same star or ejected material. A planet that is still suffering from the star's heat. It also revealed the system. Researchers consider these changes to be a possible sign of the existence of a giant planet at a distance of about 6 million kilometers from the white dwarf; A distance much less than the distance between Mercury and the Sun.

This possible planet is still exposed to intense radiation from the star and may lose its outer atmosphere. Part of the fugitive material can be dispersed around it in a trail similar to the trail of comets and then fall to the surface of the white dwarf. A discovery that changes the way scientists look at the end of the life of stars. If the researchers' interpretation is confirmed, this system will be the first known example of a second-generation planet around a white dwarf. A finding that shows that the death of stars may not only be the end of a system, but also an opportunity for the formation of new worlds. Of course, scientists have not yet observed this planet directly, and current evidence strengthens its candidacy; Therefore, the final confirmation of the nature of this celestial object requires further investigations.