Bright single-mode RR Lyrae stars: Matching <i>Gaia</i> EDR3 with pulsation and evolutionary models

Kovács, G.; Karamiqucham, Behrooz

doi:10.1051/0004-6361/202142189

Cited by 3 publications

(3 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We neglected 𝛼-enhancement. As stated by Kovacs & Karamiqucham (2021), the effect of 𝛼-enhancement on periods has an order of magnitude of 10 −3 only, hence has little influence on the results of modeling.…”

Section: Grid Of Modelsmentioning

confidence: 94%

“…Masses predicted by the evolution theory are around 10-20% higher than those predicted by the pulsation theory (e.g., Keller 2008). In the case of RR Lyrae stars, Kovacs & Karamiqucham (2021) combined pulsation modeling with evolutionary tracks for single RR Lyrae stars to derive luminosities, which were later compared with estimations based on the Gaia EDR3 data, and led to an agreement between the two methods.…”

Section: Comparison With Evolution Theorymentioning

confidence: 99%

See 1 more Smart Citation

Asteroseismology of RR Lyrae stars with non-radial modes

Netzel¹,

Smolec²

2022

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

The additional signals observed in the frequency spectra of the first-overtone RR Lyrae stars, which form a period ratio around 0.61 with the period of the first overtone, are a common phenomenon for RRc and RRd stars, as well as for first-overtone classical Cepheids. The recently proposed model explains these signals as harmonics of non-radial modes of degrees 8 or 9 in the case of RR Lyrae stars and 7, 8, or 9 in the case of classical Cepheids. We selected at least triple-mode RR Lyrae stars pulsating in radial and non-radial modes for asteroseismic modelling. We assume the identification of the non-radial modes as predicted by the model. We calculated a dense grid of models for RR Lyrae stars using envelope pulsation code. By matching first-overtone period and period ratios, we obtained physical parameters for the selected sample of triple-mode stars. It is the very first attempt of modelling RR Lyrae stars with non-radial modes. We compared our results with predictions of stellar evolution theory, which resulted in a mass discrepancy more noticeable for long-period stars: Pulsation masses seem higher than evolutionary masses. We compared metallicity estimates for RRc stars from a modelled sample with metallicities determined spectroscopically for a sample of RRc stars in the solar neighbourhood: Both distributions are consistent.

show abstract

Section: Grid Of Modelsmentioning

confidence: 94%

Section: Comparison With Evolution Theorymentioning

confidence: 99%

Asteroseismology of RR Lyrae stars with non-radial modes

Netzel¹,

Smolec²

2022

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…Although the single parameter (i.e., period) dependence of the gravity is very strong, the final formula also depends on the parameter coverage of the models. The following formula was derived from the models of Kovacs & Karamiqucham (2021b) covering the RR Lyrae parameter space and combining solar-scaled models with overall heavy element contents of Z = 0.0008 and 0.001: log g = 2.48 − 1.27 log P 0 .…”

Section: Methodsmentioning

confidence: 99%

Toward more accurate RR Lyrae metallicities

Kovacs,

Jurcsik

2023

A&A

Self Cite

View full text Add to dashboard Cite

By using a large sample of fundamental mode RR Lyrae stars with published spectroscopic iron abundances and gravities, we point out the importance of correcting these abundances by using more accurate temporal gravities. For the 197 stars with multiple spectra, overall we find [Fe/H] standard deviations of 0.167 (as published), 0.145 (shifted by data source zero points), and 0.121 (both zero point shifted and corrected for the static gravity). These improvements are significant at the ~2σ level at each correction step, leading to a clearly significant improvement after both corrections are applied. The higher quality of the gravity-corrected metallicities is also strongly supported by the tighter correlation with the metallicities predicted from the period and Fourier phase, φ31. This work highlights the need for using some external estimates of the temporal gravity in the chemical abundance analysis, rather than relying on a full-fetched spectrum fit that leads to large correlated errors in the estimated parameters.

show abstract

Asteroseismology of RR Lyrae stars with non-radial modes

Netzel,

Smolec

2022

Preprint

View full text Add to dashboard Cite

The additional signals observed in the frequency spectra of the first-overtone RR Lyrae stars, that form a period ratio around 0.61 with the period of the first overtone, are a common phenomenon for RRc and RRd stars, as well as for first-overtone classical Cepheids. The recently proposed model explains these signals as harmonics of non-radial modes of degrees 8 or 9 in the case of RR Lyrae stars and 7, 8, or 9 in the case of classical Cepheids. We selected at least triple-mode RR Lyrae stars pulsating in radial and non-radial modes for asteroseismic modeling. We assume the identification of the non-radial modes as predicted by the model. We calculated a dense grid of models for RR Lyrae stars using envelope pulsation code. By matching first overtone period and period ratios we obtained physical parameters for the selected sample of triple-mode stars. It is the very first attempt of modeling RR Lyrae stars with non-radial modes. We compared our results with predictions of stellar evolution theory, which resulted in a mass discrepancy more noticeable for long-period stars: pulsation masses seem higher than evolutionary masses. We compared metallicity estimates for RRc stars from modeled sample with metallicities determined spectroscopically for a sample of RRc stars in the solar neighbourhood: both distributions are consistent.

show abstract

Bright single-mode RR Lyrae stars: Matching Gaia EDR3 with pulsation and evolutionary models

Cited by 3 publications

References 35 publications

Asteroseismology of RR Lyrae stars with non-radial modes

Asteroseismology of RR Lyrae stars with non-radial modes

Toward more accurate RR Lyrae metallicities

Asteroseismology of RR Lyrae stars with non-radial modes

Contact Info

Product

Resources

About