J/other/RMxAA/54.15 Variable stars in NGC 6934 (Yepez+, 2018)
The variable star population in the globular cluster NGC 6934.
Yepez M.A., Arellano Ferro A., Muneer S., Giridhar S.
<Rev. Mex. Astron. Astrofis., 54, 15-36 (2018)>
=2018RMxAA..54...15Y 2018RMxAA..54...15Y (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Stars, variable ; Photometry, CCD
Keywords: globular clusters: individual: NGC 6934 - stars: variables: RR Lyrae -
stars: variables: SX Phe
Abstract:
We report an analysis of new V and I CCD time-series photometry of
the globular cluster NGC 6934. Through the Fourier decomposition of
the RR Lyrae light curves, the mean values of [Fe/H] and the distance
of the cluster were estimated, we found; [Fe/H]UVES=-1.48±0.14 and
d=16.03±0.42kpc, and [Fe/H]UVES=-1.43±0.11 and
d=15.91±0.39kpc, from the calibrations of RRab and RRc stars
respectively. Independent distance estimations from SX Phe and SR
stars are also discussed. Individual absolute magnitudes, radii and
masses are also reported for RR Lyrae stars. We found 12 new
variables: 4 RRab, 3 SX Phe, 2 W Virginis (CW) and 3 semi-regular
(SR). The inter-mode or "either-or" region in the instability strip is
shared by the RRab and RRc stars. This characteristic, observed only
in some OoI clusters and never seen in an OoII, is discussed in terms
of mass distribution in the ZAHB.
Description:
V and I time-series photometry for all confirmed variables in NGC 6934.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 87 104 General data of confirmed variables in NGC 6934
table6.dat 92 31237 VI photometry of 34 RR Lyrae, 14 SX Phe, 1 SR
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- VName Variable name, VNN
4 A1 --- n_VName [a] a for newly found in this work
6- 11 A6 --- Type Variable type
13- 18 F6.3 mag ?=- Intensity weighted V magnitude
20- 25 F6.3 mag ?=- Intensity weighted I magnitude
27- 31 F5.3 mag AV ?=- V amplitude
33- 37 F5.3 mag AI ?=- I amplitude
38 A1 --- u_AI Uncertainty flag on AI
39 A1 --- l_PKOS01 [~] Limit flag on PKOS01
40- 48 F9.6 d PKOS01 ?=- Period Kaluzni et al. (2001AJ....121.1533K 2001AJ....121.1533K)
50- 58 F9.4 d E0 ?=- Epoch (HJD-2450000)
60- 67 F8.6 d Per ?=- Period present work
69- 70 I2 h RAh ?=- Right ascension (J2000)
72- 73 I2 min RAm ?=- Right ascension (J2000)
75- 78 F4.1 s RAs ?=- Right ascension (J2000)
79 A1 --- DE- Declination sign (J2000)
80- 81 I2 deg DEd ?=- Declination (J2000)
83- 84 I2 arcmin DEm ?=- Declintaion (J2000)
86- 87 I2 arcsec DEs ?=- Declination (J2000)
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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2- 4 A3 --- VName Variable name, VNN
7 A1 --- Filter [VI] Observation filter
10- 22 F13.5 d HJD Heliocentric Julian date
25- 30 F6.3 mag magst Standard magnitude
33- 38 F6.3 mag maginst Instrumental magnitude
41- 45 F5.3 mag e_maginst ?=- Error on the magnitude
49- 57 F9.3 s-1 Fref Reference flux (in ADU/s)
60- 65 F6.3 s-1 e_Fref Error on the reference flux (in ADU/s)
68- 76 F9.3 s-1 DFlux ?=- Differential flux (in ADU/s)
79- 84 F6.3 s-1 e_DFlux ?=- Error on the differential flux (in ADU/s)
87- 92 F6.4 --- p Photometric scale factor
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Acknowledgements:
Armando Arellano Ferro, armando(at)astro.unam.mx
(End) A. Arelano Ferro [IA-UNAM, Mexico], P. Vannier [CDS] 17-May-2018