A study the period variation rate of V1292 Taurus Type RR Lyrae variable star

ABSTRACT We present an analysis of VI CCD time-series photometry of the Oo II type globular cluster M92. The variable star population of the cluster is studied with the aim of revising their classifications, identifications, frequency spectra, and to select indicators of the parental cluster metallicity and distance. The Fourier decomposition of RR Lyrae light curves lead to the estimation of mean [Fe/H]spec = −2.20 ± 0.18 and distance of 8.3 ± 0.2 kpc. Four new variables are reported: one RRd (V40), a multimode SX Phe (V41), an SR (V42), and one RRc (F1) that is most likely not a cluster member. The AC nature of V7 is confirmed. The double mode nature of the RRc star V11 is not confirmed and its amplitude modulations are most likely due to the Blazhko effect. Two modes are found in the known RRc variable V13. It is argued that the variable V30, previously classified as RRab is, in fact, a BL Her-type star not belonging to the cluster. Using the Gaia-DR2 proper motions, we identified 5012 stars in the field of the cluster, which are very likely cluster members, and for which we possess photometry, enabling the production of a refined colour–magnitude diagram. This also allowed us to identify a few variable stars that do not belong to the cluster. The RR Lyrae pulsation modes on the HB are cleanly separated by the first overtone red edge, a common feature in all Oo II-type clusters.

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A Timing Model for the RR Lyrae Variable Star TU Ursae Majoris, a Probable Member of a Binary System

The Astronomical Journal ◽

10.1086/301109 ◽

1999 ◽

Vol 118 (5) ◽

pp. 2442-2450 ◽

Cited By ~ 16

Author(s):

Richard A. Wade ◽

J. Donley ◽

Robert Fried ◽

Raymond E. White ◽

A. Saha

Keyword(s):

Binary System ◽

Variable Star ◽

Timing Model ◽

Rr Lyrae

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The MACHO Project Large Magellanic Cloud Variable‐Star Inventory. IX. Frequency Analysis of the First‐Overtone RR Lyrae Stars and the Indication for Nonradial Pulsations

The Astrophysical Journal ◽

10.1086/309530 ◽

2000 ◽

Vol 542 (1) ◽

pp. 257-280 ◽

Cited By ~ 83

Author(s):

C. Alcock ◽

R. Allsman ◽

D. R. Alves ◽

T. Axelrod ◽

A. Becker ◽

...

Keyword(s):

Frequency Analysis ◽

Variable Star ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Rr Lyrae Stars ◽

Rr Lyrae ◽

Lyrae Stars

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On the Changes of Periods of RR Lyrae Variables in the Globular Clusters M5, M53 and NGC 5053

International Astronomical Union Colloquium ◽

10.1017/s025292110003339x ◽

1973 ◽

Vol 21 ◽

pp. 101-103

Author(s):

V. P. Goranskij ◽

B. V. Kukarkin ◽

N. N. Samus’

Keyword(s):

Surface Temperature ◽

Globular Clusters ◽

Variable Star ◽

Theoretical Calculations ◽

Interior Structure ◽

Rr Lyrae ◽

Late Stages

The period of a variable star is very sensitive to extremely minor changes in luminosity, mass, radius, surface temperature, etc. of the star. With new theoretical calculations of the interior structure of stars in the late stages of evolution now available, the investigation of instabilities in the periods of the RR Lyrae variables in globular clusters becomes urgent.

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Period Variations and Evolution of Delta Scuti Variables

International Astronomical Union Colloquium ◽

10.1017/s0252921100014160 ◽

1993 ◽

Vol 134 ◽

pp. 189-191

Author(s):

Jiang Shi-Yang

Keyword(s):

Main Sequence ◽

Life Time ◽

High Amplitude ◽

Period Variation ◽

Solar Mass ◽

Period Range ◽

Variation Rate ◽

Delta Scuti ◽

Low Amplitude ◽

Scuti Stars

The Short periods of Delta Scuti Stars allow the observational detection of the period changes expected from the stellar evolution within several tens years. For about 30 years we are keeping this topic as a small systematic observational program with our 60 cm telescope. Here we publish the period variation of 18 stars in table I. The data of 28 And are taken from R. Garrido et al. in AAp 144 (1983), 211; the period variation rate of 4 CVn is given by M. Breger. Both of them are low amplitude variables.From these data we find out that both the population I and II variables can have period increasing and decreasing. The rate is between 2 × 10−6 to 8 × 10−8 days/year. Due to the period range of about 0.2 days, the time scale of period variation in one direction is limited within about 2 million to 200 million years. Usually we take the mass of this A to F type variables as 1.5 to 2.0 solar mass, so the main sequence life time is about several billion years. If all these A to F type main sequence stars will be variable in some period of its life time the possibility for a star to show Delta Scuti type variation is about hundredth, especially for the high amplitude type. Up to now we have found some 50 high amplitude variables with V < 10.5, and the total number of A3 to F5 with V < 10.5 is about 1.2 × 105, so the incidence of high amplitude variables is about 0.04%.

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