Based on time-series photometry from three totally different telescopes, a world group of astronomers has carried out an in depth asteroseismology study of WD J0049?2525—probably the most large pulsating white dwarf. The study, published May 22 on the arXiv pre-print server, resulted within the detection of latest pulsation modes of this white dwarf.
White dwarfs (WDs) are stellar cores left behind after a star has exhausted its nuclear gasoline and signify the ultimate evolutionary stage for the overwhelming majority of stars. Observations present that the majority WDs have main spectral classification DA as they exhibit hydrogen-dominated atmospheres. However, a small fraction of WDs showcases traces of heavier components.
In pulsating WDs, luminosity varies as a consequence of non-radial gravity wave pulsations inside these objects. One subtype of pulsating WDs is named DAVs, or ZZ Ceti stars, which have solely hydrogen absorption traces of their spectra.
With a mass of about 1.3 photo voltaic plenty, WD J004917.14–252556.81, or WD J0049?2525 for brief, is an ultra-massive ZZ Ceti star—probably the most large pulsating WD up to now detected. The white dwarf is situated at a distance of some 326 mild years and its efficient temperature is estimated to be roughly 13,000 Okay. Previous observations have detected two vital pulsation modes of this object.
A bunch of astronomers led by Ozcan Caliskan of Istanbul University in Turkey employed the New Technology Telescope (NTT), the Apache Point Observatory (APO) and the Gemini South telescope to conduct an asteroseismology investigation of WD J0049?2525. The predominant purpose of this study was to probe the inside of this WD.
“We current an in depth observational and asteroseismic evaluation of probably the most large pulsating WD at the moment identified, WD J0049?2525, primarily based on time-series photometry from three totally different telescopes,” the researchers wrote within the paper.
The observations allowed Caliskan’s group to determine 13 new vital pulsation frequencies of WD J0049?2525, lots of which have excessive signal-to-noise ratios. The a number of distinguished frequencies are concentrated within the vary between 3,868 µHz (258 seconds) and 5,861 (170 seconds) µHz.
Moreover, the review detected two potential frequency splittings, indicating a rotation interval of both 0.3 or 0.67 days for WD J0049?2525. The astronomers word that each prompt orbital intervals are in settlement with expectations for such an enormous WD.
Based on the collected knowledge, it was discovered that WD J0049?2525 has a mass of roughly 1.29 photo voltaic plenty and its asteroseismic distance is between 304 and 320 mild years, which is according to earlier estimates. The crystallized core mass fraction for this WD was calculated to be larger than 99%.
Summing up the outcomes, the authors of the paper underline that additional high-precision observations are needed to totally perceive the detailed construction of WD J0049?2525, particularly to constrain its rotation interval and to confirm the presence of further refined pulsation modes.
More data:
O. Caliskan et al, Asteroseismology of WD J004917.14-252556.81, the Most Massive Pulsating White Dwarf, arXiv (2025). DOI: 10.48550/arxiv.2505.17177
Journal data:
arXiv
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Asteroseismology study uncovers new pulsation modes in ultra-massive white dwarf ( 2)
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