Characterizing the Chemistry of Planetary Materials Around White Dwarf Stars

TL;DR

This paper discusses how spectroscopic analysis of white dwarf stars reveals detailed compositions of accreted planetary materials, showing many are similar to Earth and indicating differentiated structures like crust, mantle, and core.

Contribution

It demonstrates that white dwarf spectroscopy provides precise insights into the bulk compositions and differentiation of extrasolar minor planets, a novel approach in planetary science.

Findings

White dwarf photospheres contain accreted rocky planetary material.

Many extrasolar minor planets are differentiated, similar to terrestrial planets.

Elemental compositions of these bodies resemble those of Earth and solar system objects.

Abstract

Planetary systems that orbit white dwarf stars can be studied via spectroscopic observations of the stars themselves. Numerous white dwarfs are seen to have accreted mostly rocky minor planets, the remnants of which are present in the stellar photospheres. The elemental abundances in the photospheres unveil the bulk compositions of the accreted parent bodies with a precision far greater than can be attained with any other technique currently available to astronomers. The most significant discovery, overall, is that rocky extrasolar planets have bulk elemental compositions similar to those of Earth and other rocky objects in our solar system. The white dwarf studies reveal that many extrasolar minor planets (asteroids) are differentiated, possessing analogs of terrestrial crust, mantle and core; this finding has important implications for the origin of our own solar system.