Recent progress in the theoretical modelling of Cepheids and RR Lyrae stars

Marconi, M.

doi:10.1051/epjconf/201715206001

Cited by 5 publications

(4 citation statements)

References 29 publications

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“…These relations, that update previous relations published in the literature for solar metallicity models (Bono et al 2000b) are consistent with the latter, within the errors, and confirm the use of pulsation models to establish sound relations between pulsational and evolutionary parameters. Moreover they provide a very important tool to build iso-periodic model sequences to apply the light and radial velocity curves model fitting (Marconi et al 2013a;Marconi 2017). The coefficients reported in previous Table 3 show that a variation of the mixing length parameter does not significantly affect the PLMT relations.…”

Section: The Period-luminosity-mass-temperature Relationsmentioning

confidence: 95%

An Extended Theoretical Scenario for Classical Cepheids. I. Modeling Galactic Cepheids in the Gaia Photometric System

Somma

Marconi

Molinaro

et al. 2020

ApJS

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We present a new extended and detailed set of models for Classical Cepheid pulsators at solar chemical composition (Z = 0.02, Y = 0.28) based on a well tested nonlinear hydrodynamical approach. In order to model the possible dependence on crucial assumptions such as the Mass-Luminosity relation of central Helium burning intermediate-mass stars or the efficiency of superadiabatic convection, the model set was computed by varying not only the pulsation mode and the stellar mass but also the Mass-Luminosity relation and the mixing length parameter that is used to close the system of nonlinear hydrodynamical and convective equations. The dependence of the predicted boundaries of the instability strip as well as of both light and radial velocity curves on the assumed Mass-Luminosity and the efficiency of superadiabatic convection is discussed. Nonlinear Period-Mass-Luminosity-Temperature,

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Section: The Period-luminosity-mass-temperature Relationsmentioning

confidence: 95%

An Extended Theoretical Scenario for Classical Cepheids. I. Modeling Galactic Cepheids in the Gaia Photometric System

Somma

Marconi

Molinaro

et al. 2020

ApJS

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“…Unsolved problems include doublemode pulsations (Kolláth et al 2002;Smolec & Moskalik 2010) and the cyclic modulations of RR Lyrae light curves (e.g., the Blazhko effect, Blažko 1907;Szabó et al 2010). For background material we refer the reader to Gautschy & Saio (1995, Buchler (2009), andMarconi (2017).…”

Section: Namementioning

confidence: 99%

Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation

Paxton¹,

Smolec²,

Schwab³

et al. 2019

ApJS

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We update the capabilities of the open-knowledge software instrument Modules for Experiments in Stellar Astrophysics (MESA). RSP is a new functionality in MESAstar that models the non-linear radial stellar pulsations that characterize RR Lyrae, Cepheids, and other classes of variable stars. We significantly enhance numerical energy conservation capabilities, including during mass changes. For example, this enables calculations through the He flash that conserve energy to better than 0.001%. To improve the modeling of rotating stars in MESA, we introduce a new approach to modifying the pressure and temperature equations of stellar structure, and a formulation of the projection effects of gravity darkening. A new scheme for tracking convective boundaries yields reliable values of the convective-core mass, and allows the natural emergence of adiabatic semiconvection regions during both core hydrogen-and helium-burning phases. We quantify the parallel performance of MESA on current generation multicore architectures and demonstrate improvements in the computational efficiency of radiative levitation. We report updates to the equation of state and nuclear reaction physics modules. We briefly discuss the current treatment of fallback in core-collapse supernova models and the thermodynamic evolution of supernova explosions. We close by discussing the new MESA Testhub software infrastructure to enhance source-code development.

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“…RR Lyrae stars (RRLs) are low-mass pulsating giant stars that have evolved away from the main sequence, and are on the intersection of the horizontal branch and the classical instability strip of the Hertzsprung-Russell diagram. They pulsate mostly radially but on occasion, nonradial modes can be observed, which make them a good source to study the stellar evolution and stellar pulsation (for a review see e.g., Kolenberg 2012;Marconi 2017). Their pulsation modes and the shape of their lightcurves (LCs) are used to classify them into three different types: RRab type pulsates in the fundamental mode and has an asymmetric sawtooth shaped LC; RRc type pulsates in the firstovertone mode and has more sinusoidal LC than RRab; and RRd type pulsates in both the modes and also has a sinusoidal LC.…”

Section: Introductionmentioning

confidence: 99%

Study of the Blazhko Type RRc stars in the Stripe 82 Region Using SDSS and ZTF

Varma,

Benkő,

Ngeow

2023

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RR Lyrae stars (RRLs) are pulsating stars, many of which also show a long-term variation called the Blazhko effect which is a modulation of amplitude and phase of the lightcurve. In this work, we searched for the incidence rate of the Blazhko effect in the first-overtone pulsating RR Lyrae (RRc) stars of the Galactic halo. The focus was on the Stripe 82 region in the Galactic halo which was studied by Sesar et al. using the Sloan Digital Sky Survey (SDSS) data. In their work, 104 RRLs were classified as RRc type. We combined their SDSS light curves with Zwicky Transient Facility (ZTF) data, and used them to document the Blazhko properties of these RRc stars. Our analysis showed that among the 104 RRc stars, eight were rather RRd stars, and were excluded from the study. Out of the remaining 96, 34 were Blazhko type, 62 were non-Blazhko type, giving the incidence rate of 35.42% for Blazhko RRc stars. The shortest Blazhko period found was 12.808 ± 0.001 days for SDSS 747380, while the longest was 3088 ± 126 days for SDSS 3585856. Combining SDSS and ZTF data sets increased the probability of detecting the small variations due to the Blazhko effect, and thus provided a unique opportunity to find longer Blazhko periods. We found that 85% of RRc stars had the Blazhko period longer than 200 days.

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Recent progress in the theoretical modelling of Cepheids and RR Lyrae stars

Cited by 5 publications

References 29 publications

An Extended Theoretical Scenario for Classical Cepheids. I. Modeling Galactic Cepheids in the Gaia Photometric System

An Extended Theoretical Scenario for Classical Cepheids. I. Modeling Galactic Cepheids in the Gaia Photometric System

Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation

Study of the Blazhko Type RRc stars in the Stripe 82 Region Using SDSS and ZTF

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