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

¹ Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Unidad Asociada al CSIC, Plaza San Juan 1, 44001 Teruel, Spain
e-mail: clsj@cefca.es
² Department of Physics, University of Warwick, Coventry CV4 7AL, UK
³ Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, 05508-090 São Paulo, Brazil
⁴ Institut de Ciències del Cosmos, Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, 08028 Barcelona, Spain
⁵ Observatório Nacional – MCTI (ON), Rua Gal. José Cristino 77, São Cristóvão, 20921-400 Rio de Janeiro, Brazil
⁶ European Southern Observatory, Karl Schwarzschild Straße 2, Garching 85748, Germany
⁷ Centro de Astrobiología (CSIC-INTA), ESAC Campus, Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Spain
⁸ Spanish Virtual Observatory, 28692 Villanueva de la Cañada, Spain
⁹ Donostia International Physics Centre (DIPC), Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain
¹⁰ IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
¹¹ University of Michigan, Department of Astronomy, 1085 South University Ave., Ann Arbor, MI 48109, USA
¹² University of Alabama, Department of Physics and Astronomy, Gallalee Hall, Tuscaloosa, AL 35401, USA
¹³ Instituto de Astrofísica de Canarias, La Laguna, 38205 Tenerife, Spain
¹⁴ Departamento de Astrofísica, Universidad de La Laguna, 38206 Tenerife, Spain

Received: 8 July 2021
Accepted: 26 October 2021

Abstract

Aims. We estimated the spectral evolution of white dwarfs with effective temperature using the Javalambre Photometric Local Universe Survey (J-PLUS) second data release (DR2), which provides 12 photometric optical passbands over 2176 deg².

Methods. We analyzed 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- and helium-dominated atmospheres. We estimated the probability distribution functions for effective temperature (T_eff), surface gravity, parallax, and composition; and the probability of having a H-dominated atmosphere (p_H) for each source. We applied a prior in parallax, using Gaia EDR3 measurements as a reference, and derived a self-consistent prior for the atmospheric composition as a function of T_eff.

Results. We described the fraction of white dwarfs with a He-dominated atmosphere (f_He) with a linear function of the effective temperature at 5000 < T_eff < 30 000 K. We find f_He = 0.24 ± 0.01 at T_eff = 10 000 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 p_H 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 M_⊙, and T_eff > 6000 K. The result for H-dominated white dwarfs agrees with previous studies, with a dominant M = 0.59 M_⊙ peak and the presence of an excess at M ∼ 0.8 M_⊙. This high-mass excess is absent in the He-dominated distribution, which presents a single peak.

Conclusions. The J-PLUS optical data provide 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 T_eff = 20 000 K to T_eff = 5000 K.