New SX Phoenicis Stars in the Globular Cluster M53

Jeon, Young‐Beom; Lee, Myung Gyoon; Lee, Ho

doi:10.1086/375323

Cited by 36 publications

(70 citation statements)

References 27 publications

(60 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We successfully identified SXP1, SXP2, SXP6, and SXP7 among these eight objects in our data (they are identical to our V73, V74, V75, and V76, respectively). From the data published by Jeon et al (2003), SXP4, SXP5, and SXP8 have too low amplitudes to be identified in our data. The situation is different for SXP3 which has a reasonably large amplitude of 0.1 mag according to Jeon et al (2003) but it is rather close to V66 and V67 and the limited resolution of our CCD chip did not enable us to separate their light variations.…”

Section: Short-period Variablescontrasting

confidence: 76%

“…With the aid of TFA, we considerably increased the reliability of detection of short-period, low-amplitude signals by filtering out low-frequency trends from the data whose amplitudes would have overwhelmed the intrinsic light variations of these objects. All of the short-period stars previously known in M53 were discovered by Jeon et al (2003) who used a 1.8-m telescope and PSF photometry. All of these objects are of SX Phe-type located in the blue straggler region of the color-magnitude diagram (CMD).…”

Section: Short-period Variablesmentioning

confidence: 99%

“…This cluster is also very abundant in blue straggler stars (BSSs). Among the almost 200 BSSs, 8 were proven to be SX Phe variables (Jeon et al 2003). Beccari et al (2008a) showed that the BSSs follow a bimodal distribution, implying a binary rate of 10%, but no eclipsing binaries have been found so far.…”

Section: Introductionmentioning

confidence: 99%

“…Despite its high variable content and its favorable position, no comprehensive wide-field CCD time-series photometric study has been published for this cluster. Among the two previous works of similar type, Kopacki (2000) observed only the central part of the cluster, while Jeon et al (2003) limited themselves to the investigation of SX Phe stars. The present study, based on two-color photometry covering most of the cluster, intends to improve the time and spatial coverage of this cluster.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Study of globular cluster M53: new variables, distance, metallicity

Dékány

Kovács

2009

A&A

View full text Add to dashboard Cite

Aims. We study the variable star content of the globular cluster M53 to compute the physical parameters of the constituting stars and the distance of the cluster. Methods. Covering two adjacent seasons in 2007 and 2008, new photometric data are gathered for 3048 objects in the field of M53. By using the OIS (optimal image subtraction) method and subsequently TFA (trend filtering algorithm), we search for variables in the full sample by using discrete Fourier transformation and box-fitting least squares methods. We select variables based on the statistics related to these methods combined with visual inspection. Results. We identified 12 new variables (2 RR Lyrae stars, 7 short periodic stars -3 of them are SX Phe stars -and 3 long-period variables). No eclipsing binaries were found in the present sample. Except for the 3 (hitherto unknown) Blazhko RR Lyrae (two RRab and an RRc) stars, no multiperiodic variables were found. We showed that after proper period shift, the PLC (period-luminositycolor) relation for the first overtone RR Lyrae sample tightly follows the one spanned by the fundamental stars. Furthermore, the slope is in agreement with that derived from other clusters. Based on the earlier Baade-Wesselink calibration of the PLC relations, the derived reddening-free distance modulus of M53 is 16.31 ± 0.04 mag, corresponding to a distance modulus of 18.5 mag for the Large Magellanic Cloud. From the Fourier parameters of the RRab stars we obtained an average iron abundance of −1.58 ± 0.03 (error of the mean). This is ∼0.5 dex higher than the overall abundance of the giants as given in the literature and derived in this paper from the three-color photometry of giants. We suspect that the source of this discrepancy (observable also in other, low-metallicity clusters) is the lack of a sufficient number of low-metallicity objects in the calibrating sample of the Fourier method.

show abstract

Section: Short-period Variablescontrasting

confidence: 76%

Section: Short-period Variablesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Study of globular cluster M53: new variables, distance, metallicity

Dékány

Kovács

2009

A&A

View full text Add to dashboard Cite

show abstract

“…SX Phe stars are well known as distance indicators through their P-L relation (e.g. Jeon et al 2003). By adopting the P-L relation for the fundamental mode recently calculated by Cohen & Sarajedini (2012) for a sample of 77 double-mode SX Phe stars in Galactic globular clusters, which is of the form M V = −1.640(±0.110)−3.389(±0.090) log(P f ), we can calculate M V = 2.588 ± 0.157 mag for V6 assuming that it is pulsating in the fundamental mode.…”

Section: Sx Phoenicis Stars and Candidatesmentioning

confidence: 99%

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

RR Lyrae stars and the horizontal branch of NGC 5904 (M5)

Ferro

Luna

Bramich

et al. 2016

Astrophys Space Sci

View full text Add to dashboard Cite

We report the distance and [Fe/H] value for the globular cluster NGC 5904 (M5) derived from the Fourier decomposition of the light curves of selected RRab and RRc stars. The aim in doing this was to bring these parameters into the homogeneous scales established by our previous work on numerous other globular clusters, allowing a direct comparison of the horizontal branch luminosity in clusters with a wide range of metallicities. Our CCD photometry of the large variable star population of this cluster is used to discuss light curve peculiarities, like Blazhko modulations, on an individual basis. New Blazhko variables are reported.From the RRab stars we found [Fe/H] UVES = −1.335 ± 0.003(statistical) ± 0.110(systematic), and a distance of 7.6 ± 0.2 kpc, and from the RRc stars we found [Fe/H] UVES = −1.39 ± 0.03(statistical) ± 0.12(systematic) and a distance of 7.5 ± 0.3 kpc. The results for RRab and RRc stars should be considered independent since they come from different calibrations and zero points. Absolute magnitudes, radii and masses are also reported for individual RR Lyrae stars. The distance to the cluster was also calculated by alternative methods like the Period-Luminosity relation of SX Phe and the luminosity of the stars at the tip of the red giant branch, and we obtained the results 7.7 ± 0.4 and 7.2 − 7.5 kpc respectively.The distribution of RR Lyrae stars in the instability strip is discussed and compared with other clusters in connection with the Oosterhoff and horizontal branch type. The Oosterhoff type II clusters systematically show a RRab-RRc segregation about the instability strip first-overtone red edge, while the Oosterhoff type I clusters may or may not display this feature. A group of RR Lyrae stars is identified in an advanced evolutionary stage, and two of them are likely binaries with unseen companions.

show abstract

New SX Phoenicis Stars in the Globular Cluster M53

Cited by 36 publications

References 27 publications

Study of globular cluster M53: new variables, distance, metallicity

Study of globular cluster M53: new variables, distance, metallicity

Variable stars in the globular cluster NGC 7492

RR Lyrae stars and the horizontal branch of NGC 5904 (M5)

Contact Info

Product

Resources

About