Constraining the Evolution of ZZ Ceti

Mukadam, Anjum S.; Kepler, S. O.; Winget, D. E.; Nather, R. E.; Kilic, Mukremin; Mullally, Fergal; Hippel, Ted von; Kleinman, S. J.; Nitta, A.; Guzik, J. A.; Bradley, P. A.; Matthews, J.; Sekiguchi, K.; Sullivan, D. J.; Sullivan, T.; Shobbrook, R. R.; Birch, P. V.; Jiang, Xue-Jian; Xu, Dawen; Joshi, Santosh; Ashoka, B. N.; Ibbetson, P.; Leibowitz, E. M.; Ofek, E. O.; Meistas, E.; Janulis, R.; Ališauskas, D.; Kalytis, R.; Handler, G.; Kilkenny, D.; O’Donoghue, D.; Kurtz, D. W.; Müller, Mark-Christoph; Moskalik, P.; Ogłoza, W.; Zoła, S.; Krzesinski, J.; Johannessen, F.; González-Pérez, J. M.; Solheim, J. E.; Silvotti, R.; Bernabei, S.; Vauclair, G.; Dolez, N.; Fu, J. N.; Chevreton, M.; Manteiga, M.; Suárez, Olga; Ulla, A.; Cunha, M. S.; Metcalfe, T. S.; Kanaan, A.; Fraga, L.; Costa, A. F. Murillo; Giovannini, O.; Fontaine, G.; Bergeron, P.; O'Brien, M. S.; Sanwal, D.; Wood, M. A.; Ahrens, Thomas J.; Silvestri, Nicole M.; Klumpe, E. W.; Kawaler, S. D.; Riddle, R. L.; Reed, M. D.; Watson, T. K.

doi:10.1086/377044

Cited by 38 publications

(35 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Kepler 1993) is the most wellestablished method for the measurement of secular changes in pulsating star periods. Practically, its efficiency has been demonstrated by studies of several pulsating stars, such as the DAV star G117-B15A (Kepler et al 2005a,b) and the DBV star R548 (Mukadam et al 2003).…”

Section: The (O-c) Methodsmentioning

confidence: 99%

The temporal changes of the pulsational periods of the pre-white dwarf PG 1159-035

Costa¹,

Kepler²

2008

A&A

Self Cite

View full text Add to dashboard Cite

Context. PG 1159-035, a pre-white dwarf with T eff ≃ 140 000 K, is the prototype of the PG 1159 spectroscopic class and the DOV pulsating class. Pulsating pre-white dwarf stars evolve rapidly: the effective surface temperature decreases rapidly, the envelope contracts and the inner structure experiences stratification due to gravitational settling. These changes in the star generate variations in its oscillation periods. The measurement of temporal change in the oscillation periods, Ṗ, allows us to estimate directly rates of stellar evolutionary changes, such as the cooling rate and the envelope contraction rate, providing a way to test and refine evolutionary models for pre-white dwarf pulsating stars. Aims. Previously, only two pulsation modes of the highest amplitudes for PG 1159-035 have had their Ṗ measured: the 516.0 s and the 539.3 s modes. We measured the Ṗ of a larger number of pulsation modes, increasing the number of constraints for evolutionary studies of PG 1159-035. We attempted to use the secular variations in the periods of multiplets to calculate the variation in the rotational period, the envelope contraction rate, and the cooling rate of the star. Methods. The period variations were measured directly from the PG 1159-035 observational data and refined by the (O-C) method. Results. We measured 27 pulsation mode period changes. The periods varied at rates of between 1 and 100 ms/yr, and several can be directly measured with a relative standard uncertainty below 10%. For the 516.0 s mode (the highest in amplitude) in particular, not only the value of Ṗ can be measured directly with a relative standard uncertainty of 2%, but the second order period change, P, can also be calculated reliably. By using the (O-C) method, we refined the Ṗs and estimated the Ps for six other pulsation periods. As a first application, we calculated the change in the PG 1559-035 rotation period, Ṗrot = (−2.13 ± 0.05) × 10 −6 ss −1 , the envelope contraction rate Ṙ = (−2.2 ± 0.5) × 10 −13 R ⊙ s −1 , and the cooling rate Ṫ = −1.42 × 10 −3 Ks −1 .

show abstract

Section: The (O-c) Methodsmentioning

confidence: 99%

The temporal changes of the pulsational periods of the pre-white dwarf PG 1159-035

Costa¹,

Kepler²

2008

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…We can use this well-measuredṖ to constrain, among other things, the mass of the axion, the best motivated dark matter candidate and in general, the emission rate of weakly interacting particles. While measuring aṖ for R548's most stable mode (near 213 s) is less trivial because it is a doublet, the current upper limit, 5:5 AE 1:9 ; 10 À15 s s À1 (Mukadam et al 2003), also indicates that in the near future R548 may become useful to constrain the axion mass as well.…”

Section: Astrophysical Contextmentioning

confidence: 96%

Strong Limits on the DFSZ Axion Mass with G117‐B15A

Kim

Montgomery

Winget

2008

ApJ

Self Cite

View full text Add to dashboard Cite

We compute rates of period change (Ṗ) for the 215 s mode in G117-B15A and the 213 s mode in R548, first for models without axions, and then for models with axions of increasing mass. We use the asteroseismological models for G117-B15A and R548 we derived in an earlier publication. For G117-B15A, we consider two families of solutions, one with relatively thick hydrogen layers and one with thin hydrogen layers. Given the region of parameter space occupied by our models, we estimate error bars on the calculatedṖ values using Monte Carlo simulations. Together with the observedṖ for G117-B15A, our analysis yields strong limits on the DFSZ axion mass. Our thin hydrogen solutions place an upper limit of 13.5 meV on the axion, while our thick hydrogen solutions relaxes that limit to 26.5 meV.

show abstract

“…The second term represents the rate of change due to gravitational contraction (Ṙ < 0), and it is a negative contribution. In the cases in which robust measurements of secular period drifts of pulsating WDs can be achieved, a number of important applications can be -in principle -carried out (Mukadam et al 2003). In particular, the derived values ofΠ could help in calibrating the WD cooling curves, thus reducing the theoretical uncertainties of WD cosmochronology to constrain the age of the Galactic disk (e.g., Harris et al 2006), halo (e.g., Isern et al 1998), and Galactic globular clusters (e.g., Hansen et al 2013) and open clusters .…”

Section: Introductionmentioning

confidence: 99%

Pulsating low-mass white dwarfs in the frame of new evolutionary sequences

Calcaferro

Córsico

Althaus

2017

A&A

View full text Add to dashboard Cite

Context. An increasing number of low-mass (M /M 0.45) and extremely low-mass (ELM, M /M 0.18−0.20) white-dwarf stars are being discovered in the field of the Milky Way. Some of these stars exhibit long-period g-mode pulsations, and are called ELMV variable stars. Also, some low-mass pre-white dwarf stars show short-period p-mode (and likely radial-mode) photometric variations, and are designated as pre-ELMV variable stars. The existence of these new classes of pulsating white dwarfs and pre-white dwarfs opens the prospect of exploring the binary formation channels of these low-mass white dwarfs through asteroseismology. Aims. We aim to present a theoretical assessment of the expected temporal rates of change of periods (Π) for such stars, based on fully evolutionary low-mass He-core white dwarf and pre-white dwarf models. Methods. Our analysis is based on a large set of adiabatic periods of radial and nonradial pulsation modes computed on a suite of low-mass He-core white dwarf and pre-white dwarf models with masses ranging from 0.1554 to 0.4352 M , which were derived by computing the non-conservative evolution of a binary system consisting of an initially 1 M ZAMS star and a 1.4 M neutron star companion. Results. We computed the secular rates of period change of radial ( = 0) and nonradial ( = 1, 2) g and p modes for stellar models representative of ELMV and pre-ELMV stars, as well as for stellar objects that are evolving just before the occurrence of CNO flashes at the early cooling branches. We find that the theoretically expected magnitude ofΠ of g modes for pre-ELMVs is by far larger than for ELMVs. In turn,Π of g modes for models evolving before the occurrence of CNO flashes are larger than the maximum values of the rates of period change predicted for pre-ELMV stars. Regarding p and radial modes, we find that the larger absolute values ofΠ correspond to pre-ELMV models. Conclusions. We conclude that any eventual measurement of a rate of period change for a given pulsating low-mass pre-white dwarf or white dwarf star could shed light about its evolutionary status. Also, in view of the systematic difficulties in the spectroscopic classification of stars of the ELM Survey, an eventual measurement ofΠ could help to confirm that a given pulsating star is an authentic low-mass white dwarf and not a star from another stellar population.

show abstract

Constraining the Evolution of ZZ Ceti

Cited by 38 publications

References 40 publications

The temporal changes of the pulsational periods of the pre-white dwarf PG 1159-035

The temporal changes of the pulsational periods of the pre-white dwarf PG 1159-035

Strong Limits on the DFSZ Axion Mass with G117‐B15A

Pulsating low-mass white dwarfs in the frame of new evolutionary sequences

Contact Info

Product

Resources

About