J-PLUS: Spectral evolution of white dwarfs by PDF analysis

TL;DR

This study uses J-PLUS photometry and Bayesian analysis to investigate the spectral evolution of white dwarfs, estimating atmospheric compositions and mass distributions across a large sample with high statistical reliability.

Contribution

It introduces a Bayesian method combining Gaia and J-PLUS data to determine white dwarf atmospheric types and their evolution with temperature, providing new insights into spectral composition fractions.

Findings

He-dominated fraction increases by 21% from 20000K to 5000K.

The mass distribution shows a dominant peak at 0.59 Msun and an excess at 0.8 Msun for hydrogen atmospheres.

The method reliably classifies white dwarf atmospheres using photometric data.

Abstract

We estimated the spectral evolution of white dwarfs with effective temperature using the Javalambre Photometric Local Universe Survey (J-PLUS) second data release (DR2), that provides twelve photometric optical passbands over 2176 deg2. We analysed 5926 white dwarfs with r <= 19.5 mag in common between a white dwarf catalog defined from Gaia EDR3 and J-PLUS DR2. We performed a Bayesian analysis by comparing the observed J-PLUS photometry with theoretical models of hydrogen (H) and helium (He) dominated atmospheres. We estimated the PDF for effective temperature (Teff), surface gravity, parallax, and spectral type; and the probability of having a H-dominated atmosphere (pH) for each source. We applied a prior in parallax, using Gaia EDR3 measurements as reference, and derived a self-consistent prior for the atmospheric composition as a function of Teff. We described the fraction of He-dominated atmosphere white dwarfs (fHe) with a linear function of Teff at 5000 < Teff < 30000 K. We found fHe = 0.24 +- 0.01 at Teff = 10000 K, a change rate along the cooling sequence of 0.14 +- 0.02 per 10 kK, and a minimum He-dominated fraction of 0.08 +- 0.02 at the high-temperature end. We tested the obtained pH by comparison with spectroscopic classifications, finding that it is reliable. We estimated the mass distribution for the 351 sources with distance d < 100 pc, mass M > 0.45 Msun, and Teff > 6000 K. The result for H-dominated white dwarfs agrees with previous work, with a dominant M = 0.59 Msun peak and the presence of an excess at M ~ 0.8 Msun. This high-mass excess is absent in the He-dominated distribution, which presents a single peak. The J-PLUS optical data provides a reliable statistical classification of white dwarfs into H- and He-dominated atmospheres. We find a 21 +- 3 % increase in the fraction of He-dominated white dwarfs from Teff = 20000 K to Teff = 5000 K.