Period Changes in ω Centauri RR Lyrae Stars

Jurcsik, J.; Clement, Christine M.; Geyer, E. H.; Domsa, I.

doi:10.1086/318746

Cited by 45 publications

(86 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Clearly, the phased light curve is now much improved, but we still observe possible amplitude modulations, which may be due to the Blazhko effect. This period change rate is higher than other values found in the literature by a factor of two or more (Le Borgne et al 2007;Lee 1991;Jurcsik et al 2001), but given our limited data we cannot speculate on the cause.…”

Section: Rr Lyrae Starscontrasting

confidence: 79%

Variable stars in the globular cluster NGC 7492

Jaimes

Ferro

Bramich

et al. 2013

A&A

View full text Add to dashboard Cite

Aims. We have performed a photometric V, R, I CCD time-series analysis with a baseline of about eight years of the outer-halo globular cluster NGC 7492 with the aim of searching for new variables and using these (and the previously known variables) to determine the physical parameters of interest for the cluster (e.g. metallicity, absolute magnitude of the horizontal branch, distance, etc.). Methods. We used difference image analysis to extract precise light curves in the relatively crowded star field, especially towards the densely populated central region. Several different approaches were used for variability detection that recover the known variables and lead to new discoveries. We determined the physical parameters of the only RR0 star using a light-curve Fourier decomposition analysis. Results. We found one new long-period variable and two SX Phe stars in the blue straggler region. We also present one candidate SX Phe star that requires follow-up observations. Assuming that the SX Phe stars are cluster members and using the period-luminosity relation for these stars, we estimate their distances as ∼25.2 ± 1.8 and 26.8 ± 1.8 kpc, and identify their possible modes of oscillation. We refined the periods of the two RR Lyrae stars in our field of view. We found that the RR1 star V2 is undergoing a period change and possibly exhibits the Blazhko effect. A Fourier decomposition of the light curve of the RR0 star V1 allowed us to estimate a metallicity of [Fe/H] ZW ∼ −1.68 ± 0.10 or [Fe/H] UVES ∼ −1.64 ± 0.13, a log-luminosity log(L/L ) ∼ 1.76 ± 0.02, an absolute magnitude M V ∼ 0.38 ± 0.04 mag, and a true distance modulus of μ 0 ∼ 16.93 ± 0.04 mag, which is equivalent to a distance of ∼24.3 ± 0.5 kpc. All of these values are consistent with previous estimates in the literature.

show abstract

Section: Rr Lyrae Starscontrasting

confidence: 79%

Variable stars in the globular cluster NGC 7492

Jaimes

Ferro

Bramich

et al. 2013

A&A

View full text Add to dashboard Cite

show abstract

“…We also note that the period ranges are nearly coincident in the two samples; in particular, we have a mean and median value of 0.53 d for stars with increasing period, and a mean and median value of 0.51 d for stars with decreasing period. This similarity is not observed for RRab stars in galactic clusters (Lee 1991;Jurcsik et al 2001), where positive rates are largely more frequent.…”

Section: Comparison Between Stars With Period Changes Of Opposite Signmentioning

confidence: 71%

“…The theoretical sequences calculated by Dorman (1992) predict a blueward evolution at slightly lower luminosities, crossing the instability strip in fewer cases (e.g., Fig. 7 in Jurcsik et al 2001). In general, all theoretical models predict a blueward evolution in connection with the prevalence of the H-shell burning over the He-central burning.…”

Section: Comparison Between Stars With Period Changes Of Opposite Signmentioning

confidence: 75%

“…2,3 are only available in electronic form at http://www.aanda.org period decreases. Such rates have been observed in some cluster stars (Jurcsik et al 2001), but it is unclear in which evolutionary phase they occur (Sweigart & Renzini 1979).…”

Section: Introductionmentioning

confidence: 91%

“…In the literature it is more common to indicate the rate of period changes using the β parameter, expressed in [d Myr −1 ] (e.g., Lee 1991;Jurcsik et al 2001). The β values can be calculated from the second-order fits by applying…”

Section: Stars With a Linearly Variable Periodmentioning

confidence: 99%

See 2 more Smart Citations

Stellar evolution through the ages: period variations in galactic RRab stars as derived from the GEOS database and TAROT telescopes

Borgne¹,

Paschke²,

Vandenbroere³

et al. 2007

A&A

View full text Add to dashboard Cite

Context. The theory of stellar evolution can be more closely tested if we have the opportunity to measure new quantities. Nowadays, observations of galactic RR Lyr stars are available on a time baseline exceeding 100 years. Therefore, we can exploit the possibility of investigating period changes, continuing the pioneering work started by V. P. Tsesevich in 1969. Aims. We collected the available times of maximum brightness of the galactic RR Lyr stars in the GEOS RR Lyr database. Moreover, we also started new observational projects, including surveys with automated telescopes, to characterise the O-C diagrams better. Methods. The database we built has proved to be a very powerful tool for tracing the period variations through the ages.

show abstract

References

2015

Pulsating Stars

View full text Add to dashboard Cite

Period Changes in ω Centauri RR Lyrae Stars

Cited by 45 publications

References 20 publications

Variable stars in the globular cluster NGC 7492

Variable stars in the globular cluster NGC 7492

Stellar evolution through the ages: period variations in galactic RRab stars as derived from the GEOS database and TAROT telescopes

References

Contact Info

Product

Resources

About