RR Lyrae: Theory versus Observation

Kollath, Zoltán; Buchler, J. R.; Feuchtinger, M. U.

doi:10.1086/309330

Cited by 13 publications

(9 citation statements)

References 18 publications

(17 reference statements)

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“…More recently Feuchtinger et al (2000) compared a calculation which used the diffusion approximation against a calculation which used time dependent radiative transfer and found only small differences in the pulsation amplitude. In addition Kolláth et al (2000) explored the use of the radiation diffusion approximation near the surface and concluded that differences between observations and models are not a result of this inadequate treatment of the radiation transport. Because we are performing calculations that have large computational requirements, including anything more sophisticated than radiation diffusion would likely appreciably increase the computational requirements of an already highly compu-tationally intensive simulation.…”

Section: Radiation Diffusionmentioning

confidence: 99%

Radial Stellar Pulsation and Three-Dimensional Convection. Ii. Two-Dimensional Convection in Full Amplitude Radial Pulsation

Geroux

Deupree

2013

ApJ

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We have developed a three-dimensional radiation hydrodynamics code to simulate the interaction of convection and radial pulsation in classical variable stars. One key goal is the ability to carry these simulations to full amplitude in order to compare them with observed light curves. Previous multi-dimensional calculations were prevented from reaching full amplitude because of drift in the radial coordinate system, due to the algorithm defining radial movement of the coordinate system during the pulsation cycle. We have removed this difficulty by defining our radial coordinate flow algorithm to require that the mass in a spherical shell remains constant for every time-step throughout the pulsation cycle. We have used our new code to perform two-dimensional (2D) simulations of the interaction of radial pulsation and convection. We have made comparisons between light curves from our 2D convective simulations with observed light curves and find that our 2D simulated light curves are better able to match the observed light curve shape near the red edge of the RR Lyrae instability strip than light curves from previous one-dimensional time dependent convective models.

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Section: Radiation Diffusionmentioning

confidence: 99%

Radial Stellar Pulsation and Three-Dimensional Convection. Ii. Two-Dimensional Convection in Full Amplitude Radial Pulsation

Geroux

Deupree

2013

ApJ

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“…Kolláth et al 2000), which yields to a distance modulus m − M (V5) = 15. m 7. On the other hand, there are a few longer period δ Scuti stars known with periods between 0.25 and 0.3 days (Rodríguez & Breger 2001), that could be evolved massive δ Scuti variables.…”

Section: Cluster Membership Of the Variable Starsmentioning

confidence: 99%

A variable star survey of the open cluster M 37

Kiss

Szabó

Sziladi

et al. 2001

A&A

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Abstract.A CCD photometric study of the dense galactic open cluster M 37 is presented and discussed. The majority of the analysed data are time-series measurements obtained through an RC filter. The observations were carried out on seven nights between December 1999 and February 2000, and have led to the discovery of 7 new variable stars in the field. Three of them have been unambiguously identified as W UMa-type eclipsing binaries, while two more are monoperiodic pulsating stars, most probably high-amplitude δ Scuti-type variables. The remaining two stars seem to be long-period eclipsing binaries without firm period determination. Johnson B and V frames have been used to construct a new colour-magnitude (CM) diagram of the cluster, and to find the locations of the new variable stars. The pulsating variables are most likely background objects. The CM diagram is fitted with recent isochrones yielding the main parameters of the cluster.

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“…Comparison with the mean absolute magnitude of the RRab Lyrae in M3 recently obtained by Kaluzny et al (1998) using the same approach, is again suggestive of a slightly fainter HB level in NGC 6229 than in M3, as required in order to account for a period shift between the RRab variables in the two clusters. For an analysis of possible problems related to this method, the reader is refered to Kolláth, Buchler & Feuchtinger (2000) and Jurcsik & Kovács (1999).…”

Section: Physical Properties Of Rr Lyrae Stars From Their Fourier Pmentioning

confidence: 99%

The outer-halo globular cluster NGC 6229 - IV. Variable stars

Borissova¹,

Catelan²,

Valchev³

2001

Monthly Notices of the Royal Astronomical Society

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A B S T R A C TWe present time-series B, V photometry of NGC 6229, obtained with the purpose of providing the first extensive CCD variability study of this cluster. As a result, we were able to obtain periods for all NGC 6229 variables, with the exception of five stars from the candidate list of Borissova et al. located very close to the cluster centre. Two stars suspected to be variables by Carney, Fullton and Trammell are first-overtone RR Lyrae (RRc) stars, whereas seven of the 12 candidates of Borissova et al. are confirmed variables ± three of them being fundamental RR Lyrae (RRab) pulsators, two first-overtone pulsators, one an eclipsing binary (most likely an Algol system) and one a bright star whose variability status could not be satisfactorily determined. A new image subtraction method (ISM) suggested by Alard has been employed which, together with the Welch±Stetson technique, has allowed us to discover twelve new RR Lyrae variables in the cluster, for which ephemerides are provided. Ten of these are RRabs, whereas the other two are RRcs. As originally suggested by Mayer, NGC 6229 is clearly an Oosterhoff type I globular cluster. We also confirm that V8 is a Population II Cepheid of the W Virginis type, and suspect that this is the case for V22 as well. The physical properties of the NGC 6229 RR Lyrae population are contrasted with those of M3 (NGC 5272) using several different methods, including a standard periodshift analysis. Possible differences between these two clusters are discussed. (MC) ² Hubble Fellow. ³ It is with deep sorrow that we announce that T. Valchev passed away, at the age of 31, on 1999 December 31, at the Pirin Mountain, Bulgaria.

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RR Lyrae: Theory versus Observation

Cited by 13 publications

References 18 publications

Radial Stellar Pulsation and Three-Dimensional Convection. Ii. Two-Dimensional Convection in Full Amplitude Radial Pulsation

Radial Stellar Pulsation and Three-Dimensional Convection. Ii. Two-Dimensional Convection in Full Amplitude Radial Pulsation

A variable star survey of the open cluster M 37

The outer-halo globular cluster NGC 6229 - IV. Variable stars

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