A SPECTROSCOPIC SEARCH FOR CHEMICALLY STRATIFIED WHITE DWARFS IN THE SLOAN DIGITAL SKY SURVEY
AffiliationUniv Arizona, Steward Observ
stars: fundamental parameters
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationA SPECTROSCOPIC SEARCH FOR CHEMICALLY STRATIFIED WHITE DWARFS IN THE SLOAN DIGITAL SKY SURVEY 2016, 833 (2):127 The Astrophysical Journal
JournalThe Astrophysical Journal
Rights© 2016. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractWe present a detailed search and analysis of chemically stratified hybrid (traces of helium and hydrogen) white dwarfs in the Sloan Digital Sky Survey (SDSS). Only one stratified white dwarf, PG 1305-017, was known prior to this analysis. The main objective is to confirm the existence of several new stratified objects. We first describe our new generation of stratified model atmospheres, where a thin hydrogen layer floats in diffusive equilibrium on top of a more massive helium layer. We then present the results of our search for hot (T-eff > 30,000 K) white dwarfs with a hybrid spectral type among the similar to 38,000 white dwarf spectra listed in the SDSS. A total of 51 spectra were retained in our final sample, which we analyze using spectroscopic fits to both chemically homogeneous and stratified model atmospheres. We identify 14 new stratified white dwarfs in the SDSS sample. From these results, we draw several conclusions regarding the physical processes that might explain the presence of helium in the atmospheres of all the stars in our sample.
VersionFinal published version
SponsorsNSERC Canada; Fund FRQ-NT (Quebec); Gemini Observatory [GS-2015B-Q-68]