J/MNRAS/493/1996 NGC 6712 variable stars VI light curves (Deras+, 2020)
NGC 6712: the variable star population of a tidally disrupted globular cluster.
Deras D., Arellano Ferro A., Lazaro C., Bustos Fierro I.H., Calderon J.H.,
Muneer S., Giridhar S.
<Mon. Not. R. Astron. Soc., 493, 1996-2014 (2020)>
=2020MNRAS.493.1996D 2020MNRAS.493.1996D (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Photometry, VRI
Keywords: stars: fundamental parameters - stars: variables: RR Lyrae -
globular clusters: individual: NGC 6712
Abstract:
We present an analysis of VI CCD time-series photometry of globular
cluster NGC 6712. Our main goal is to study the variable star
population as indicators of the cluster mean physical parameters. We
employed the Fourier decomposition of RR Lyrae light curves to confirm
that [Fe/H]UVES=-1.0±0.05 is a solid estimate. We estimated the
reddening to the cluster as E(B-V)=0.35±0.04 from the RRab stars
colour curves. The distance to the cluster was estimated using three
independent methods which yielded a weighted mean distance
=8.1±0.2kpc. The distribution of RRab and RRc stars on the
horizontal branch shows a clear segregation around the first overtone
red edge of the instability strip, which seems to be a common feature
in OoI-type cluster with a very red horizontal branch. We carried out
a membership analysis of 60447 stars in our field of view (FoV) using
the data from Gaia-DR2 and found 1529 likely members; we possess the
light curves of 1100 among the member stars. This allowed us to
produce a clean colour-magnitude diagram, consistent with an age of
12Gyr, and enabled us to discover close unresolved contaminants for
several variable stars. From the proper motion analysis, we found
evidence of non-member stars in the FoV of the cluster being tidally
affected by the gravitational pull of the bulge of the Galaxy. We
found that the RRab variable V6, shows a previously undetected Blazhko
effect. Finally, we report 16 new variables of the EW-type (9) and
SR-type (7).
Description:
The data used in this work were obtained from two sites. The first set
of data was obtained with the 0.80m IAC80 telescope at the
Observatorio del Teide (Tenerife, Spain), during 10 non-consecutive
nights, between 2016 June 13th and July 16th. We used the CAMELOT
camera with 2048x2048-pixels and 0.304arcsec/pixel, with a
10.4x10.4-arcmin2 FoV, and a back illuminated detector CCD42-40 from
E2V Technologies. The second set of data was obtained using the 2m
telescope at the Indian Astronomical Observatory (IAO) in Hanle, India
on 12 nights separated into four intermittent seasons between 2011
June and 2018 April. The detector used was a SITe ST-002 thinned
backside illuminated CCD of 2048x2048-pixels with a scale of
0.296arcsec/pix, which translates into a FoV of approximately
10.1x10.1-arcmin2.
V and I time-series CCD photometry for known variables in the
10.1'x10.1' filed of view of NGC 6712.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 105 30 Data of member variable stars in NGC 6712 in
the FoV of our images.
table4.dat 105 12 Data of known, unclassified, and newly discovered
field variable stars (FV) in NGC 6712 in
the FoV of our images
table5.dat 47 11 Physical parameters of EW stars in NGC 6712 in
the FoV of our images (Section 4.4)
table6.dat 113 14 Fourier coefficients Ak for k=0,1,2,3,4 and phases
from the cosine series phi(c)21, phi(c)31,
phi(c)41, for RRab and RRc
table7.dat 101 15 Physical parameters obtained from the Fourier fit
for the RRab and RRc stars
table2.dat 50 39852 VI photometry of 42 variables in the field of
NGC 6712
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See also:
J/AJ/121/3114 : UBVR photometry of NGC 6712 with VLT (Paltrinieri+, 2001)
Byte-by-byte Description of file: table3.dat table4.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- VName Variable name (G1)
4 A1 --- n_VName Note on VName (1)
6- 12 A7 --- Type Type
13 A1 --- n_Type Note on Type (1)
14- 18 F5.2 mag <Vmag> Mean V magnitude
19 A1 --- n_<Vmag> Note on <Vmag> (1)
21- 25 F5.2 mag <Imag> ? Mean I magnitude
26 A1 --- n_<Imag> Note on <Imag> (1)
28 A1 --- l_AmpV Limit flag on AmpV
29- 32 F4.2 mag AmpV ? Amplitude of variation in V band
34 A1 --- l_AmpI Limit flag on AmpI
35- 38 F4.2 mag AmpI ? Amplitude of variation in I band
40- 49 F10.6 d Per ? Period
50 A1 --- n_Per Note on Per (1)
52- 60 F9.4 d HJDmax ? Time of maximum brightness
61 A1 --- n_HJDmax Note on HJDmax (1)
63- 64 I2 h RAh Right ascension (J2000)
66- 67 I2 min RAm Right ascension (J2000)
69- 73 F5.2 s RAs Right ascension (J2000)
75 A1 --- DE- Declination sign (J2000)
76- 77 I2 deg DEd Declination (J2000)
79- 80 I2 arcmin DEm Declination (J2000)
82- 85 F4.1 arcsec DEs Declination (J2000)
87-105 I19 --- GaiaDR2 Gaia-DR2 Source
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Note (1): Notes as follows:
a = The period is from Oosterhoff (1943BAN.....9..399O 1943BAN.....9..399O)
b = Time of primary minimum light
c = The period is from Sloan et al. (2010ApJ...719.1274S 2010ApJ...719.1274S)
d = Classified as RRab in this work, see Section A3
e = Reclassified as RRab in this work. See Section A4
f = New variable discovered in this work
g = Magnitude-weighted mean
h = Member variable candidate. Bl denotes Blazhko effect
i = Reclassified as EW in this work, see Section A6
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- VName Variable name (G1)
5- 8 F4.2 mag E(B-V) Redenning
10- 12 F3.1 kpc Dist Distance
14- 17 F4.2 Msun M1 Mass of primary
19- 22 F4.2 --- q Mass ratio, M2/M1
24- 27 I4 K Teff1 Effective temperature on primary
29- 32 F4.2 --- T2/1 Effective temperature ratio, Teff2/Teff1
34- 37 F4.2 Rsun R1 Radius on primary
39- 42 F4.2 Rsun R2 Radius of secondary
44- 47 F4.1 deg i Inclination
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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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1- 4 A4 --- Type [RRab RRc] Type
6- 8 A3 --- VName Variable name (G1)
11- 16 F6.3 mag A0 Fourier coefficient A0 for Vmag
18- 22 F5.3 mag e_A0 Fourier coefficient A0 error
24- 28 F5.3 mag A1 Fourier coefficient A1 for Vmag
30- 34 F5.3 mag e_A1 Fourier coefficient A1 error
36- 40 F5.3 mag A2 Fourier coefficient A2 for Vmag
42- 46 F5.3 mag e_A2 Fourier coefficient A2 error
48- 52 F5.3 mag A3 Fourier coefficient A3 for Vmag
54- 58 F5.3 mag e_A3 Fourier coefficient A3 error
60- 64 F5.3 mag A4 Fourier coefficient A4 for Vmag
66- 70 F5.3 mag e_A4 Fourier coefficient A4 error
72- 77 F6.4 --- phi21 Phase for the cosine series φ(c)21
79- 84 F6.4 --- e_phi21 Phase for the cosine series φ(c)21 error
85- 90 F6.4 --- phi31 Phase for the cosine series φ(c)31
92- 97 F6.4 --- e_phi31 Phase for the cosine series φ(c)31 error
99-103 F5.3 --- phi41 Phase for the cosine series φ(c)41
105-109 F5.3 --- e_phi41 Phase for the cosine series φ(c)41 error
111-113 F3.1 --- Dm ? Deviation parameter Dm for the RRab stars (see
Jurcsik & Kovacs, 1996, Cat. J/A+A/312/111)
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Type [RRab RRc] Type
6- 8 A3 --- VName Variable name (G1)
9 A1 --- n_VName Note on VName (1)
10- 11 A2 --- WM [wm ] wm for
Weighted mean for the RR type
14- 18 F5.2 [-] [Fe/H]JK96ZW ZW metallicity from JK96 (2)
20- 23 F4.2 [-] e_[Fe/H]JK96ZW ZW metallicity from JK96 error
25- 29 F5.2 [-] [Fe/H]JK96UVES UVES metallicity from JK96 (2)
31- 34 F4.2 [-] e_[Fe/H]JK96UVES UVES metallicity from JK96 error
36- 40 F5.2 [-] [Fe/H]N13UVES UVES metallicity from N13 (2)
42- 45 F4.2 [-] e_[Fe/H]N13UVES UVES metallicity from N13 error
47- 51 F5.3 mag VMAG Absolute V magnitude
53- 57 F5.3 mag e_VMAG Absolute V magnitude error
59- 63 F5.3 [K] logTeff Effective temperature
65- 69 F5.3 [K] e_logTeff Effective temperature error
71- 75 F5.3 [Lsun] logL Luminosity
77- 81 F5.3 [Lsun] e_logL Luminosity error
83- 86 F4.2 Msun Mass Mass
88- 91 F4.2 Msun e_Mass Mass error
93- 96 F4.2 Rsun Rad Radius
98-101 F4.2 Rsun e_Rad Radius error
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Note (1): a: Not included in the [Fe/H] averages
Note (2): JK96 : Jurcsik & Kovacs, 1996, Cat. J/A+A/312/111)
N13 : Nemec et al. (2013ApJ...773..181N 2013ApJ...773..181N)
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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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2- 4 A3 --- VName Variable name (G1)
10 A1 --- Filter [VI] Observation filter
15- 27 F13.5 d HJD Heliocentric Julian date
30- 35 F6.3 mag magst Standard magnitude
38- 43 F6.3 mag maginst Instrumental magnitude
46- 50 F5.3 mag e_maginst Error on the magnitude
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Global notes:
Note (G1): Variable name:
VNN (cluster members), FVN (not cluster members) and C
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Acknowledgements:
Armando Arellano Ferro, armando(at)astro.unam.mx
(End) A. Arelano Ferro [IA-UNAM, Mexico], P. Vannier [CDS] 16-Jul-2020