A giant planet orbiting a hot white dwarf with a semi-major axis of around 15 solar radii will undergo substantial evaporation with expected mass loss rates comparable to the accretion rate that we observe onto the white dwarf. The composition of this disk is unlike all other known planetary debris around white dwarfs 7, but resembles predictions for the makeup of deeper atmospheric layers of icy giant planets, with H 2O and H 2S being major constituents. Here we report optical spectroscopy of a hot (about 27,750 kelvin) white dwarf, WD J091405.30+191412.25, that is accreting from a circumstellar gaseous disk composed of hydrogen, oxygen and sulfur at a rate of about 3.3 × 10 9 grams per second. Gravitational scattering of planetesimals towards the white dwarf requires the presence of more massive bodies 6, yet no planet has so far been detected at a white dwarf. The composition of these planetesimals is similar to that of rocky bodies in the inner Solar System 5. 2) confirmed that the photospheric trace metals found in many white dwarfs 3 arise from the accretion of tidally disrupted planetesimals 4. The detection 1 of a dust disk around the white dwarf star G29-38 and transits from debris orbiting the white dwarf WD 1145+017 (ref.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |