Evidence for this ongoing consumption arises from the Keck Observatory's spectroscopic observations, which detected thirteen chemical elements in the star's atmosphere. These heavy elements likely originated from a rocky body at least 120 miles (200 kilometers) wide that was destabilized by gravitational forces and pulled into the white dwarf's debris disk within the last few million years.
Lead author Erika Le Bourdais of the Trottier Institute for Research on Exoplanets emphasized, "This discovery challenges our understanding of planetary system evolution. Ongoing accretion at this stage suggests white dwarfs may also retain planetary remnants still undergoing dynamical changes."
Patrick Dufour, a Universite de Montreal co-author, noted, "The amount of rocky material is unusually high for a white dwarf of this age," highlighting the system's dynamic past. Hydrogen-rich white dwarf atmospheres typically obscure such elemental traces, making this detection particularly significant.
John Debes of the Space Telescope Science Institute stated, "There's still a reservoir of material capable of polluting the white dwarf, even after billions of years. Something clearly disturbed this system long after the star's death."
Further investigation shows that heavy element pollution in white dwarfs is relatively common, with nearly half accreting such material. In the case of LSPM J0207+3331, planetary orbits were likely destabilized by a recent perturbation, causing tidal disruption and accretion to continue well past the main-sequence phase. Debes noted, "Mass loss during stellar evolution can destabilize orbits, affecting planets, comets, and asteroids."
The scenario points to delayed instability triggered by interactions among surviving planets or by external factors, with Jupiter-sized exoplanets still potentially undetectable due to distance and temperature. ESA's Gaia telescope and NASA's James Webb Space Telescope may provide vital data on possible distant planets within this system. Debes added, "Future observations may help distinguish between a planetary shakeup or the gravitational effect of a stellar close encounter with the white dwarf."
These results were published in The Astrophysical Journal Letters.
Research Report:Ancient planetary system around a polluted hydrogen-rich white dwarf star undergoing accretion
Related Links
Space Telescope Science Institute
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth
| Subscribe Free To Our Daily Newsletters |
| Subscribe Free To Our Daily Newsletters |
