English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present a spectroscopic survey of 230 white dwarf candidates within 40 pcof the Sun from the William Herschel Telescope and Gran Telescopio Canarias.All candidates were selected from $\textit{Gaia}$ Data Release 2 (DR2) and inalmost all cases had no prior spectroscopic classifications. We find a total of191 confirmed white dwarfs and 39 main-sequence star contaminants. The majorityof stellar remnants in the sample are relatively cool ($\langle T_{\rm eff}\rangle$ = 6200 K), showing either hydrogen Balmer lines or a featurelessspectrum, corresponding to 89 DA and 76 DC white dwarfs, respectively. We alsorecover two DBA white dwarfs and 9--10 magnetic remnants. We find twocarbon-bearing DQ stars and 14 new metal-rich white dwarfs. This includes thepossible detection of the first ultra-cool white dwarf with metal lines. Wedescribe three DZ stars for which we find at least four different metalspecies, including one which is strongly Fe- and Ni-rich, indicative of theaccretion of a planetesimal with core-Earth composition. We find one extremelymassive (1.31 $\pm$ 0.01 M$_{\odot}$) DA white dwarf showing weak Balmer lines,possibly indicating stellar magnetism. Another white dwarf shows strong Balmerline emission but no infrared excess, suggesting a low-mass sub-stellarcompanion. High spectroscopic completeness ($>$99%) has now been reached for$\textit{Gaia}$ DR2 sources within 40 pc sample, in the northern hemisphere($\delta >$ 0 deg) and located on the white dwarf cooling track in theHertzsprung-Russell diagram. A statistical study of the full northern sample ispresented in a companion paper.

$\textit{Gaia}$ white dwarfs within 40 pc I: spectroscopic observations of new candidates