J-PLUS: The fraction of calcium white dwarfs along the cooling sequence

Aims . We used the Javalambre Photometric Local Universe Survey (J-PLUS) second data release (DR2) photometry in 12 optical bands over 2176 deg 2 to estimate the fraction of white dwarfs with the presence of Ca II H+K absorption along the cooling sequence. Methods . We compared the J-PLUS photometry against metal-free theoretical models to estimate the equivalent width in the J 0395 passband of 10 nm centered at 395 nm (EW J 0395 ), a proxy to detect calcium absorption. A total of 4399 white dwarfs with effective temperatures within 30 000 > T eff > 5500 K and masses of M > 0.45 M ⊙ were analyzed. Their EW J 0395 distribution was modeled using two populations, corresponding to polluted and non-polluted systems, to estimate the fraction of calcium white dwarfs ( f Ca ) as a function of T eff . The probability of each individual white dwarf presenting calcium absorption, p Ca , was also computed. Results . The comparison of EW J 0395 with both the measured Ca/He abundance and the identification of metal pollution from spectroscopy shows that EW J 0395 correlates with the presence of Ca II H+K absorption. The fraction of calcium white dwarfs changes along the cooling sequence, increasing from f Ca ≈ 0 at T eff = 13 500 K to f Ca ≈ 0.15 at T eff = 5500 K. This trend reflects the selection function of calcium white dwarfs in the optical. We compare our results with the fractions derived from the 40 pc spectroscopic sample and from Sloan Digital Sky Survey (SDSS) spectra. The trend found in J-PLUS observations is also present in the 40 pc sample; however, SDSS shows a deficit of metal-polluted objects at T eff < 12 000 K. Finally, we found 39 white dwarfs with p Ca > 0.99. Twenty of them have spectra presented in previous studies, whereas we obtained follow-up spectroscopic observations for six additional targets. These 26 objects were all confirmed as metal-polluted systems. Conclusions . The J-PLUS optical data provide a robust statistical measurement for the presence of Ca II H+K absorption in white dwarfs. We find a 15 ± 3% increase in the fraction of calcium white dwarfs from T eff = 13 500 K to 5500 K, which reflects their selection function in the optical from the total population of metal-polluted systems.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2024-10-17
DOI
https://doi.org/10.1051/0004-6361/202451226
Citations
2
Primary Topic
Stellar, planetary, and galactic studies
Type
article
Field-Weighted Citation Impact
0.66

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article

J-PLUS: The fraction of calcium white dwarfs along the cooling sequence

T. Civera, A. Marín-Franch, F. Jiménez-Esteban, L. Schmidtobreick et al.
2 citations
Astronomy and Astrophysics
Stellar, planetary, and galactic studies
0.66
article

J-PLUS: The fraction of calcium white dwarfs along the cooling sequence

T. Civera, A. Marín-Franch, F. Jiménez-Esteban, L. Schmidtobreick, Raúl E. Angulo, Mairi W O’Brien, Renato A. Dupke, H. Domínguez Sánchez, C. López-Sanjuán, M. Moles, D. Cristóbal-Hornillos, J. Varela, Pier-Emmanuel Tremblay, J. M. Carrasco, A. Ederoclite, Mark Hollands, N. P. Gentile Fusillo, A. Rebassa-Mansergas, J. A. Fernández-Ontiveros, Andrés del Pino, A. J. Cenarro, A. Hernán-Caballero, C. Hernández–Monteagudo, D. Spinoso, L. Sodré, H. Vázquez Ramió, Boris T. Gänsicke
article en
2 citations

Abstract

Aims . We used the Javalambre Photometric Local Universe Survey (J-PLUS) second data release (DR2) photometry in 12 optical bands over 2176 deg 2 to estimate the fraction of white dwarfs with the presence of Ca II H+K absorption along the cooling sequence. Methods . We compared the J-PLUS photometry against metal-free theoretical models to estimate the equivalent width in the J 0395 passband of 10 nm centered at 395 nm (EW J 0395 ), a proxy to detect calcium absorption. A total of 4399 white dwarfs with effective temperatures within 30 000 > T eff > 5500 K and masses of M > 0.45 M ⊙ were analyzed. Their EW J 0395 distribution was modeled using two populations, corresponding to polluted and non-polluted systems, to estimate the fraction of calcium white dwarfs ( f Ca ) as a function of T eff . The probability of each individual white dwarf presenting calcium absorption, p Ca , was also computed. Results . The comparison of EW J 0395 with both the measured Ca/He abundance and the identification of metal pollution from spectroscopy shows that EW J 0395 correlates with the presence of Ca II H+K absorption. The fraction of calcium white dwarfs changes along the cooling sequence, increasing from f Ca ≈ 0 at T eff = 13 500 K to f Ca ≈ 0.15 at T eff = 5500 K. This trend reflects the selection function of calcium white dwarfs in the optical. We compare our results with the fractions derived from the 40 pc spectroscopic sample and from Sloan Digital Sky Survey (SDSS) spectra. The trend found in J-PLUS observations is also present in the 40 pc sample; however, SDSS shows a deficit of metal-polluted objects at T eff < 12 000 K. Finally, we found 39 white dwarfs with p Ca > 0.99. Twenty of them have spectra presented in previous studies, whereas we obtained follow-up spectroscopic observations for six additional targets. These 26 objects were all confirmed as metal-polluted systems. Conclusions . The J-PLUS optical data provide a robust statistical measurement for the presence of Ca II H+K absorption in white dwarfs. We find a 15 ± 3% increase in the fraction of calcium white dwarfs from T eff = 13 500 K to 5500 K, which reflects their selection function in the optical from the total population of metal-polluted systems.

Astronomy and AstrophysicsVol. 691
University of Warwick (GB), Centro de Estudios de Física del Cosmos de Aragón (ES), Universitat de Barcelona (ES), Tsinghua University (CN)
National Science Foundation, Smithsonian Institution, U.S. Department of Energy, Alfred P. Sloan Foundation, Yale University, Carnegie Institution of Washington, Vanderbilt University, Princeton University, Ohio State University, Harvard University, University of Utah, University of Washington, Johns Hopkins University, University of Arizona, Carnegie Mellon University, University of Notre Dame, University of Portsmouth, New Mexico State University, Ministerio de Ciencia, Innovación y Universidades, Carnegie Institution for Science, European Space Agency, York University, University of Oxford, European Commission, Fundação de Amparo à Pesquisa do Estado de São Paulo, Generalitat de Catalunya, Ministério da Ciência, Tecnologia e Inovação, Financiadora de Estudos e Projetos, Ministerio de Ciencia e Innovación, Universidad Nacional Autónoma de México, Universitat de Barcelona, Jiangsu Association for Science and Technology, Max-Planck-Institut für Astrophysik, Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Canarias, Office of Science, College of Engineering, Michigan State University, University of Colorado Boulder, Leibniz-Gemeinschaft, Agència de Gestió d'Ajuts Universitaris i de Recerca, European Regional Development Fund, Agencia Estatal de Investigación, Institut de Ciències del Cosmos, Brookhaven National Laboratory, Lawrence Berkeley National Laboratory
Openalex Percentile: Top 27%
Stellar, planetary, and galactic studies
0.66
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