Constraining the evolution of ZZ Ceti

Autor(en)

Anjum S. Mukadam, S O Kepler, Beverley J. Winget, R. Edward Nather, M Kilic, F Mullally, Ted A. von Hippel, Scot J. Kleinman, Atsuko Nitta, Joyce Ann Guzik, Paul A. Bradley, Jaymie M. Matthews, Kazuhiro Sekiguchi, Denis J. Sullivan, Tiri Sullivan, R R Shobbrook, Peter V. Birch, Xianjun J. Jiang, Dawei W. Xu, Santosh Joshi, B N Ashoka, P. A. Ibbetson, Elia M. Leibowitz, Eran O. Ofek, E G Meistas, R Janulis, D Alisauskas, Romualdas Kalytis, Gerald Handler, D Kilkenny, Darragh O'Donoghue, Donald W. Kurtz, M Müller, Pawel A. Moskalik, W Ogloza, S Zola, J Krzesinski, F Johannessen, J M Gonzalez Perez, Jan Erik Solheim, R Silvotti, S Bernabei, G Vauclair, Noel Dolez, Jian Ning Fu, M Chevreton, M Manteiga, O Suarez, Ana Ulla, Margarida S. Cunha, Travis S. Metcalfe, Antonio Kanaan, L Fraga, A F M Costa, O Giovannini, Gilles Fontaine, Pierrette Bergeron, M. Sean O'Brien, Divas Sanwal, Matt A. Wood, T J Ahrens, Nicole M. Silvestri, Eric W. Klumpe, Steven D. Kawaler, Reed L. Riddle, Mike D. Reed, Todd K. Watson

Abstrakt

We report our analysis of the stability of pulsation periods in the DAV star (pulsating hydrogen atmosphere white dwarf) ZZ Ceti, also called R548. Based on observations that span 31 years, we conclude that the period 213.132605 s observed in ZZCeti drifts at a rate dP/dt≤(5.5±1.9) ×10̃¹⁵ s/s, after correcting for proper motion. Our results are consistent with previous P values for this mode and an improvement over them due to the larger time-base. The characteristic stability timescale implied for the pulsation period is |P/P|≥1.2 Gyr, comparable to the theoretical cooling timescale for the star. Our current stability limit for the period 213.132605 s is only slightly less than the present measurement for G117-B15A for the period 215.2 s, another DAV, establishing this mode in ZZ Ceti as the second most stable optical clock known, more stable than atomic clocks and most pulsars. Constraining the cooling rate of ZZ Ceti aids theoretical evolutionary models and white dwarf cosmochronology. The drift rate of this clock is small enough that reflex motion caused by any orbital planets is detectable within limits; our P constraint places limits on the mass and/or distance of any orbital companions.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

University of Washington, Universidade Federal do Rio Grande do Sul, University of Texas, Austin, Kitt Peak National Observatory, Apache Point Observatory, Los Alamos National Laboratory, University of British Columbia (UBC), Subaru Telescope, Victoria University of Wellington, Australian National University, Perth Observatory, Chinese Academy of Sciences (CAS), Uttar Pradesh State Observatory, Indian Space Research Organization, Tel Aviv University, California Institute of Technology (Caltech), Vilnius University (VU), South African Astronomical Observatory (SAAO), University of Cape Town, University of Central Lancashire, Polish Academy of Sciences (PAS), Pedagogical University of Cracow, University of Tromsø - The Arctic University of Norway, University of Oslo, COROT Additional Program Working Group, Universidad de La Laguna, Observatoire Midi-Pyrénées, Laboratoire d’Astrophysique de Toulouse-Tarbes, Beijing Normal University, Université de recherche Paris Sciences et Lettres, Universidad de Vigo, Universidade do Porto, Universidade Federal de Santa Catarina, Université de Montréal, Yale University, Florida Institute of Technology, Iowa State University, Case Western Reserve University, Southwestern University

Journal

The Astrophysical Journal: an international review of astronomy and astronomical physics

Band

594

Seiten

961-970

Anzahl der Seiten

10

ISSN

0004-637X

Publikationsdatum

2003

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie

Sustainable Development Goals

SDG 3 – Gesundheit und Wohlergehen

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/c86e218e-ed12-4d88-a385-f3e725da191f