### Abstract

We compute the phase lags between the radial velocity curves and the light curves ΔΦ_{1} = φ_{1}
^{Vr} - φ_{1}
^{mag} for classical Cepheid model sequences both in the linear and the nonlinear regimes. The nonlinear phase lags generally fall below the linear ones except for high-period models, in which they lie above, and of course for low pulsation amplitudes, in which the two merge. The calculated phase lags show good agreement with the available observational data of normal amplitude Galactic Cepheids. The metallicity has but a moderate effect on the phase lag, while the mass-luminosity relation and the parameters of the turbulent convective model (time-dependent mixing length) mainly influence the modal selection and the period, which is then reflected in the period-ΔΦ_{1} diagram. We discuss the potential application of this observable as a discriminant for pulsation modes and as a test for ultralow-amplitude (ULA) pulsation.

Original language | English |
---|---|

Pages (from-to) | 1150-1160 |

Number of pages | 11 |

Journal | Astrophysical Journal |

Volume | 667 |

Issue number | 2 I |

DOIs | |

Publication status | Published - 2007 |

### Fingerprint

### Keywords

- Cepheids
- Instabilities
- Stars: oscillations

### ASJC Scopus subject areas

- Nuclear and High Energy Physics
- Space and Planetary Science

### Cite this

*Astrophysical Journal*,

*667*(2 I), 1150-1160. https://doi.org/10.1086/520917

**The Cepheid phase lag revisited.** / Szabó, R.; Buchler, J. Robert; Bartee, Justin.

Research output: Contribution to journal › Article

*Astrophysical Journal*, vol. 667, no. 2 I, pp. 1150-1160. https://doi.org/10.1086/520917

}

TY - JOUR

T1 - The Cepheid phase lag revisited

AU - Szabó, R.

AU - Buchler, J. Robert

AU - Bartee, Justin

PY - 2007

Y1 - 2007

N2 - We compute the phase lags between the radial velocity curves and the light curves ΔΦ1 = φ1 Vr - φ1 mag for classical Cepheid model sequences both in the linear and the nonlinear regimes. The nonlinear phase lags generally fall below the linear ones except for high-period models, in which they lie above, and of course for low pulsation amplitudes, in which the two merge. The calculated phase lags show good agreement with the available observational data of normal amplitude Galactic Cepheids. The metallicity has but a moderate effect on the phase lag, while the mass-luminosity relation and the parameters of the turbulent convective model (time-dependent mixing length) mainly influence the modal selection and the period, which is then reflected in the period-ΔΦ1 diagram. We discuss the potential application of this observable as a discriminant for pulsation modes and as a test for ultralow-amplitude (ULA) pulsation.

AB - We compute the phase lags between the radial velocity curves and the light curves ΔΦ1 = φ1 Vr - φ1 mag for classical Cepheid model sequences both in the linear and the nonlinear regimes. The nonlinear phase lags generally fall below the linear ones except for high-period models, in which they lie above, and of course for low pulsation amplitudes, in which the two merge. The calculated phase lags show good agreement with the available observational data of normal amplitude Galactic Cepheids. The metallicity has but a moderate effect on the phase lag, while the mass-luminosity relation and the parameters of the turbulent convective model (time-dependent mixing length) mainly influence the modal selection and the period, which is then reflected in the period-ΔΦ1 diagram. We discuss the potential application of this observable as a discriminant for pulsation modes and as a test for ultralow-amplitude (ULA) pulsation.

KW - Cepheids

KW - Instabilities

KW - Stars: oscillations

UR - http://www.scopus.com/inward/record.url?scp=35348870291&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=35348870291&partnerID=8YFLogxK

U2 - 10.1086/520917

DO - 10.1086/520917

M3 - Article

VL - 667

SP - 1150

EP - 1160

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2 I

ER -