Rocky planetesimals as the origin of metals in DZ stars
نویسندگان
چکیده
The calcium and hydrogen abundances, Galactic positions and kinematics of 146 DZ white dwarfs from the Sloan Digital Sky Survey are analysed to constrain the possible origin of their externally polluted atmospheres. There are no correlations found between their accreted calcium abundances and spatial–kinematical distributions relative to interstellar material. Furthermore, two thirds of the stars are currently located above the Galactic gas and dust layer, and their kinematics indicate multi-Myr residences in this region where interstellar material is
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