1. Constraining the Evolution of ZZ Ceti
- Author
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Mukadam A. S., Kepler S. O., Winget D. E., Nather R. E., Kilic M., Mullally F., Hippel T. von, Kleinman S. J., Nitta A., Guzik J. A., Bradley P. A., Matthews J., Sekiguchi K., Sullivan D. J., Shobbrook R. R., Birch P., Jiang X. J., Xu D. W., Joshi S., Ashoka B.N., Ibbetson P., Leibowitz E., Ofek E. O., Meištas E. G., Janulis R., Ališauskas D., Kalytis R., Handler G., Kilkenny D., O’Donoghue D., Kurtz D. W., Müller M., Moskalik P., Ogłoza W., Zoła S., Krzesiński J., Johannessen F., Gonzalez-Perez J. M., Solheim J-E., Silvotti R., Bernabei S., Vauclair G., Dolez N., Fu J. N., Chevreton M., Manteiga M., Súarez O., Ulla A., Cunha M. S., Metcalfe T. S., Kanaan A., Fraga L., Costa A. F. M., Giovannini O., Fontaine G., Bergeron P., O’Brien M. S., Sanwal D., Wood M. A., Ahrens T. J., Silvestri N., Klumpe E. W., Kawaler S. D., Riddle R., Reed M. D., and Watson T. K.
- Subjects
stars ,white dwarfs ,individual ,ZZ Cet ,R548 - stars ,pulsations ,evolution ,Astronomy ,QB1-991 - Abstract
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 ZZ Ceti drifts at a rate dP/dt≤(5.5±1.9)×10−15 s/s, after correcting for proper motion. Our results are consistent with previous Ṗ 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/ Ṗ|≥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.
- Published
- 2003
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