2020/10/05 by Olivier Vincent, P. Bergeron, Pierre Bergeron +1 · 34 citations
Physics and Astronomy · Social Sciences · #Amplitude #Astronomy and Astrophysical Research #Educational Leadership and Practices #Instability #Instability strip #Parallax #Southern Hemisphere #Stars #Stellar, planetary, and galactic studies #Variable star #White dwarf #astro-ph.SR
paper · pdf · doi:10.3847/1538-3881/abbe20
published in The Astronomical Journal 160(6), 252 (Institute of Physics) · 39 pages, 10 figures. Accepted for publication in The Astronomical Journal
arxiv created 2020/10/05 · openalex created_date 2020/10/15 · openalex publication_date 2020/11/06 · arxiv updated 2020/11/18 · openalex updated_date 2026/08/05
Abstract The Gaia satellite recently released parallax measurements for ∼260,000 high-confidence white dwarf candidates, allowing for precise measurements of their physical parameters. By combining these parallaxes with Pan-STARRS and u -band photometry, we measured the effective temperature and stellar mass for all white dwarfs in the Northern Hemisphere within 100 pc of the Sun, and identified a sample of ZZ Ceti white dwarf candidates within the so-called instability strip. We acquired high-speed photometric observations for 90 candidates using the PESTO camera attached to the 1.6 m telescope at the Mont-Mégantic Observatory. We report the discovery of 38 new ZZ Ceti stars, including two very rare ultramassive pulsators. We also identified five possibly variable stars within the strip, in addition to 47 objects that do not appear to show any photometric variability. However, several of those could be variable with an amplitude below our detection threshold, or could be located outside the instability strip due to errors in their photometric parameters. In the light of our results, we explore the trends of the dominant period and amplitude in the M – plane, and briefly discuss the question of the purity of the ZZ Ceti instability strip (i.e., a region devoid of non-variable stars).