J/MNRAS/452/727 NGC 6229 variable VI light curves (Arellano Ferro+, 2015)
Revisiting the variable star population in NGC 6229 and the structure
of the horizontal branch.
Arellano Ferro A., Mancera Pina P.E., Bramich D.M., Giridhar S.,
Ahumada J.A., Kains N., Kuppuswamy K.
<Mon. Not. R. Astron. Soc. 452, 727 (2015)>
=2015MNRAS.452..727A 2015MNRAS.452..727A (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Stars, variable ; Photometry
Keywords: globular clusters: individual: NGC 6229 - stars: variables: RR Lyrae
Abstract:
We report an analysis of new V and I CCD time series photometry of the
distant globular cluster NGC 6229. The principal aims were to explore
the field of the cluster in search of new variables, and to Fourier
decompose the RR Lyrae light curves in pursuit of physical parameters.
We found 25 new variables: 10 RRab, 5 RRc, 6 SR, 1 CW, 1 SX Phe, and 2
that we were unable to classify. Secular period changes were detected
and measured in some favourable cases. The classifications of some of
the known variables were rectified. The Fourier decomposition of RRab
and RRc light curves was used to independently estimate the mean
cluster value of [Fe/H] and distance. From the RRab stars we found
[Fe/H]UVES =-1.31±0.01(statistical)±0.12(systematic)
([Fe/H]ZW=-1.42) and a distance of 30.0±1.5kpc, and from the RRc
stars we found [Fe/H]UVES=-1.29±0.12 and a distance of
30.7±1.1kpc, respectively. Absolute magnitudes, radii and masses are
also reported for individual RR Lyrae stars. Also discussed are the
independent estimates of the cluster distance from the tip of the red
giant branch, 34.9±2.4kpc and from the period-luminosity relation
of SX Phe stars, 28.9±2.2kpc. The distribution of RR Lyrae stars in
the horizontal branch shows a clear empirical border between stable
fundamental and first overtone pulsators which has been noted in
several other clusters; we interpret it as the red edge of the first
overtone instability strip.
Description:
VI time-series photometry of known and newly discovered variable stars
in NGC 6229.
Objects:
---------------------------------------------
RA (2000) DE Designation(s)
---------------------------------------------
16 46 58.6. +47 31 36.4 NGC 6229 = GCl 47
---------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 115 73 General data for all of the confirmed variables
in NGC 6229 in the FoV of our images (table 3)
and positions of the 3 non-variable stars
table4.dat 110 24 Fourier coefficients Ak for k = 0, 1, 2, 3, 4,
and phases φ21, φ31 and φ41,
for RRab and RRc stars.
table5.dat 80 26 Physical parameters for the RRab and RRc stars
table2.dat 79 50617 Time-series VI photometry of variables stars
in NGC 6229
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See also:
J/ApJ/102/17 : NGC 6229 variable stars V light (Baade+, 1945)
J/other/MmSAI/31.187 : Light curves of 12 variables in NGC 6229 (Mannino, 1960)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- VName Variable name (1)
5- 12 A8 --- VType Variable type (2)
14- 19 F6.3 mag <Vmag> ? Average V magnitude (3)
21- 26 F6.3 mag <Imag> ? Average I magnitude (3)
28- 31 F4.2 mag AmpV ?=- Amplitude in V band
33- 36 F4.2 mag AmpI ?=- Amplitude in I band
38- 47 F10.7 d Per ?=- Period
49- 54 F6.3 d/Myr beta ?=- Slope beta
56- 64 F9.4 d HJD ?=- Maximum brightness date (HJD-2450000)
66- 73 F8.5 d PerB ?=- Period from Borissova et al.,
2001MNRAS.324...77B 2001MNRAS.324...77B
75- 76 I2 h RAh Right ascension (J2000)
78- 79 I2 min RAm Right ascension (J2000)
81- 85 F5.2 s RAs Right ascension (J2000)
87 A1 --- DE- Declination sign (J2000)
88- 89 I2 deg DEd Declination (J2000)
91- 92 I2 arcmin DEm Declination (J2000)
94- 97 F4.1 arcsec DEs Declination (J2000)
99-115 A17 --- Note Note for non-variable stars
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Note (1): Cl* NGC 6229 Saw VNNN in Simbad. Stars V49-V73 are new discoveries
in this work.
Note (2): Label 'Bl' is used for Blazhko variables.
Note (3): The number of digits quoted for <Vmag> and <Imag> depend on the
scatter and/or amplitude modulations seen in each light curve.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- Type RR Lyrae type
6- 8 A3 --- VName Variable name
10- 15 F6.3 mag A0 A0 Fourier amplitude in Vmag
17- 21 F5.3 mag e_A0 rms uncertainty on A0
23- 27 F5.3 mag A1 A1 Fourier amplitude in Vmag
29- 33 F5.3 mag e_A1 rms uncertainty on A1
35- 39 F5.3 mag A2 A2 Fourier amplitude in Vmag
41- 45 F5.3 mag e_A2 rms uncertainty on A2
47- 51 F5.3 mag A3 A3 Fourier amplitude in Vmag
53- 57 F5.3 mag e_A3 rms uncertainty on A3
59- 63 F5.3 mag A4 A4 Fourier amplitude in Vmag
65- 69 F5.3 mag e_A4 rms uncertainty on A4
71- 75 F5.3 --- phi21 φ21 Fourier phase
77- 81 F5.3 --- e_phi21 rms uncertainty on phi21
83- 87 F5.3 --- phi31 φ31 Fourier phase
89- 93 F5.3 --- e_phi31 rms uncertainty on phi31
95- 99 F5.3 --- phi41 φ41 Fourier phase
101-105 F5.3 --- e_phi41 rms uncertainty on phi41
107-110 F4.1 --- Dm ?=- Deviation parameter
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- Type RR Lyrae type
6- 8 A3 --- VName Variable name
9 A1 --- n_VName [ab] Note on Name (1)
10- 11 A2 --- Mean [WM ] WM when weighted mean of the RR Lyrae
type for the following values
13- 18 F6.3 [-] [Fe/H] ?=- UVES metallicity
20- 24 F5.3 [-] e_[Fe/H] ? rms uncertainty on [Fe/H]
26- 30 F5.3 mag VMAG ?=- Absolute V magnitude
32- 36 F5.3 mag e_VMAG ? rms uncertainty on Vmag
38- 42 F5.3 [K] logTeff Effective temperature
44- 48 F5.3 [K] e_logTeff ? rms uncertainty on Teff
50- 54 F5.3 [Lsun] logL ?=- Luminosity
56- 60 F5.3 [Lsun] e_logL ? rms uncertainty on logL
62- 65 F4.2 Msun Mass ?=- Mass
67- 70 F4.2 Msun e_Mass ?=- rms uncertainty on Mass
72- 75 F4.2 Rsun R ?=- Radius
77- 80 F4.2 Rsun e_R ?=- rms uncertainty on R
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Note (1): Notes as follows:
a = No [Fe/H] estimate since Dm>4.1. V36 has a very peculiar value of phi31
b = No MV estimate since star falls off the HB
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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- 4 A4 --- VName Variable name, VNN
5 A1 --- Filt [VI] Observation filter
7- 19 F13.5 d HJD Heliocentric Julian date
21- 26 F6.3 mag magst Standard magnitude
28- 33 F6.3 mag maginst Instrumental magnitude
35- 39 F5.3 mag e_maginst Error on the magnitude
41- 49 F9.3 s-1 Fref Reference flux (in ADU/s)
51- 55 F5.3 s-1 e_Fref Error on the reference flux (in ADU/s)
57- 65 F9.3 s-1 Fdiff Differential flux (in ADU/s)
67- 72 F6.3 s-1 e_Fdiff Error on the differential flux (in ADU/s)
74- 79 F6.4 --- p [0.1094/1.0148] Photometric scale factor
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Acknowledgements:
Armando Arellano Ferro, armando(at)astro.unam.mx
History:
* 14-Sep-2015: First on-line version
* 21-Jan-2016: tables 4 and 5 added (from electronic version)
* 15-Feb-2016: table5: uncertainties on mass corrected
(End) Armando Arelano Ferro [IA-UNAM Mexico], Patricia Vannier [CDS] 11-Sep-2015