A team of astronomers has made a remarkable discovery involving a white dwarf star, identified as LSPM J0207+3331, which is approximately 3 billion years old and located 145 light-years from Earth in the constellation Triangulum. This ancient stellar remnant is actively accreting material from its previous planetary system, a finding that challenges existing theories regarding the evolution of stellar remnants.
The research was conducted using the High Resolution Echelle Spectrometer (HIRES) at the W. M. Keck Observatory in Hawaii. The team detected spectroscopic evidence of 13 chemical elements typically found in rocky bodies, including sodium, magnesium, aluminum, silicon, calcium, titanium, chromium, manganese, iron, cobalt, nickel, copper, and strontium. These minerals are believed to have originated from a differentiated rocky body that measured at least 200 kilometers in diameter before being disrupted by the star”s gravitational pull.
The findings, which were published in The Astrophysical Journal Letters on October 22, reveal that the surrounding debris disk is the oldest and most metal-rich ever documented around a hydrogen-rich white dwarf. Lead author Érika Le Bourdais from the iREX Institute stated, “This discovery challenges our understanding of planetary system evolution,” highlighting the ongoing accretion of material at this late stage of a star”s life.
White dwarfs, such as LSPM J0207+3331, are often referred to as “polluted” because they are surrounded by clouds of heavy elements. Nearly half of the observed white dwarfs exhibit signs of accreting these heavy elements, yet their hydrogen-rich atmospheres often obscure these elements, making this detection particularly significant. The presence of heavy elements implies that these stars likely retained planetary systems that underwent dynamic disturbances, potentially caused by interactions with a passing star or rogue planet.
In the case of LSPM J0207+3331, the researchers estimate that the recent perturbation occurred within the last few million years, likely causing the rocky body to spiral inward toward the star. This conclusion is supported by the unusually high amount of rocky material detected, which is atypical for a white dwarf of its age. The team proposes that this system may exemplify delayed instability, where interactions among multiple planets gradually destabilize their orbits over billions of years.
Co-investigator John Debes of the Space Telescope Science Institute emphasized the next steps for the research team, which will involve investigating what may have caused the disruption in the system. A Jupiter-sized planet in orbit around LSPM J0207+3331 could be the culprit, although visually detecting such a planet poses challenges. The European Space Agency”s Gaia Observatory may help identify any outer planets through gravitational influence measurements. Additionally, infrared observations from NASA”s James Webb Space Telescope could assist in locating potential outer planets in this intriguing system.
This groundbreaking research not only reshapes current assumptions about late-stage stellar evolution but also enhances our understanding of the potential fate of our own Solar System in the distant future.
