Asteroseismology of the ZZ Ceti star KUV 08368+4026

Li, C.; Fu, J.-N.; Vauclair, G.; Dolez, N.; Fox-Machado, L.; Michel, R.; Chavez, M.; Bertone, E.
Monthly Notices of the Royal Astronomical Society, Volume 449, Issue 4, p.3360-3369 (2015).


Asteroseismology is a unique tool to explore the internal structure of stars through both observational and theoretical research. The internal structure of pulsating hydrogen shell white dwarfs (ZZ Ceti stars) detected by asteroseismology is regarded as the representative of all DA white dwarfs. Observations for KUV 08368+4026, which locates in the middle of the ZZ Ceti instability strip, have been carried out in 1999 and from 2009 to 2012 with either single-site runs or multisite campaigns. Time series photometric data of about 300 h were collected in total. Through data reduction and analysis, 30 frequencies were extracted, including four triplets, two doublets, one single mode and further signals. The independent modes are identified as either l = 1 or l = 2 modes. Hence, a rotation period of 5.52 ± 0.22 d was deduced from the period spacing in the multiplets. Theoretical static models were built and a best-fitting model for KUV 08368+4026 was obtained with 0.692 ± 0.002 M, (2.92 ± 0.02) × 10-3L and the hydrogen mass fraction of 10-4 stellar mass.