White dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 16

TL;DR

This paper analyzes Sloan Digital Sky Survey Data Release 16 to classify and characterize 2410 white and blue stars, providing new identifications and atmospheric parameters for a subset, enhancing understanding of stellar evolution and galactic structure.

Contribution

It presents the spectral classification of over 2400 stars, introduces new identifications of white dwarf subtypes, and reports atmospheric parameters for a subset, expanding the catalog of known white dwarfs.

Findings

Identified 1404 DAs, 189 DZs, 103 DCs, 12 DBs, and 9 CVs.

Provided atmospheric parameters and masses for 660 stars with high-quality spectra.

Discovered fewer new white dwarfs compared to previous SDSS releases.

Abstract

White dwarfs are the end state of the evolution of more than 97% of all stars, and therefore carry information on the structure and evolution of the Galaxy through their luminosity function and initial-to-final mass relation. Examining the new spectra of all white or blue stars in the Sloan Digital Sky Survey Data Release 16, we report the spectral classification of 2410 stars, down to our identification cut-off of signal-to-noise ratio equal to three. We newly identify 1404 DAs, 189 DZs, 103 DCs, 12 DBs, and 9 CVs. The remaining objects are a mix of carbon or L stars (dC/L), narrow-lined hydrogen-dominated stars (sdA), dwarf F stars and P Cyg objects. As white dwarf stars were not targeted by SDSS DR16, the number of new discoveries is much smaller than in previous releases. We also report atmospheric parameters and masses for a subset consisting of 555 new DAs, 10 new DBs, and 85 DZs for spectra with signal-to-noise ratio larger than 10.