Astronomers Identify First Green White Dwarf in Survey of 151 Stars
Updated
Updated · CNN · Oct 16
Astronomers Identify First Green White Dwarf in Survey of 151 Stars
3 articles · Updated · CNN · Oct 16
Summary
A survey of 151 white dwarfs within 20 parsecs of Earth found the first one that would appear green to human eyes, based on calculations from its spectrum rather than direct observation.
Helium in the star’s atmosphere interacting with trace elements drove the unusual color shift; the green dwarf shows calcium, sodium and lithium, while another object in the sample appeared nearly salmon pink.
Those surface elements can come from rocky debris such as asteroids or remnants of planetary systems falling onto white dwarfs, letting astronomers infer the chemistry of destroyed planets.
Mark Hollands said upcoming spectroscopic surveys could deliver a tenfold increase in white dwarfs with spectra, potentially expanding the tally from 1 or 2 green candidates to 10 or 20.