Chen, J, Ferraro, FR, Cadelano, M, Salaris, M, Lanzoni, B, Pallanca, C, Althaus, LG and Dalessandro, E (2021) Slowly cooling white dwarfs in M13 from stable hydrogen burning. Nature Astronomy. ISSN 2397-3366

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Abstract

White dwarfs (WDs) are the final evolutionary product of the vast majority of stars in the Universe. They are electron-degenerate structures characterized by no stable thermonuclear activity, and their evolution is generally described as a pure cooling process. Their cooling rate is adopted as cosmic chronometer to constrain the age of several Galactic populations, including the disk, globular and open clusters. By analysing high-resolution photometric data of two very similar Galactic globular clusters (M3 and M13), we find a clear-cut and unexpected overabundance of bright WDs in M13. Theoretical models suggest that, consistent with the horizontal branch morphology, this overabundance is due to a slowing down of the cooling process in ~70% of the WDs in M13, caused by stable thermonuclear burning in their residual hydrogen-rich envelope. The presented observational evidence of quiescent thermonuclear activity occurring in cooling WDs brings new attention on the use of the WD cooling rate as cosmic chronometer for low-metallicity environments.

Item Type:	Article
Additional Information:	Chen, J., Ferraro, F.R., Cadelano, M. et al. Slowly cooling white dwarfs in M13 from stable hydrogen burning. Nat Astron (2021). https://doi.org/10.1038/s41550-021-01445-6
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	Nature Publishing Group
Date Deposited:	20 Sep 2021 11:00
Last Modified:	06 Mar 2022 00:50
DOI or ID number:	10.1038/s41550-021-01445-6
URI:	https://researchonline.ljmu.ac.uk/id/eprint/15518

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