Lithium pollution of a white dwarf records the accretion of an extrasolar planetesimal

We report the detection of lithium, sodium, potassium, and calcium in the atmosphere of the white dwarf Gaia DR2 4353607450860305024, which we ascribe to the accretion of a planetesimal. Using model atmospheres, we determine abundance ratios of these elements, and, with the exception of lithium, they are consistent with meteoritic values in the Solar System. We compare the measured lithium abundance with measurements in old stars and with expectations from Big Bang nucleosynthesis.

Source: ScienceNOW - January 7, 2021 Category: Science Authors: Kaiser, B. C., Clemens, J. C., Blouin, S., Dufour, P., Hegedus, R. J., Reding, J. S., Bedard, A. Tags: Astronomy, Geochemistry, Geophysics, Planetary Science reports Source Type: news