J/AJ/166/95 Parameteres for 88 giant variable star candidates (Cortes+, 2023)
Variability in NGC 3201 Giant Stars.
Cortes C.C., Llancaqueo Albornoz A., Villanova S., Ahumada J.A.,
Parisi C.
<Astron. J., 166, 95 (2023)>
=2023AJ....166...95C 2023AJ....166...95C
ADC_Keywords: Clusters, globular; Stars, giant; Stars, variable; Photometry, VRI
Keywords: Globular star clusters ; Variable stars
Abstract:
We present the analysis of 510 light curves in V and I bands of 255
giant stars in the globular cluster NGC-3201. Our aim is to expand the
sample of new types of variables reported in a previous study. These
variables show a short period (PV<0.6day) and a low amplitude
(AV<0.06mag.). We first searched for variability using the generalized
Lomb-Scargle and phase dispersion minimization periodograms of the
sample, discarding 167 stars as non-variables. We then applied the
significance test and reduced the sample to 88 giants, of which we
classified 18 as possible variables, 11 as dubious, 41 as
non-variables, and 18 as variables. We finally determined the cluster
membership of this sample and grouped each star based on their
light-curve shape. The discovered variables show periods in the range
0.2440<PV<0.5868days and amplitudes between 0.010<AV<0.064 mag. Within
the sample of 18 variable stars, we report the discovery of an object
with a period PV=0.3603±0.0012 and amplitude AV=0.703±0.029
mag that shows a RR-Lyrae ab-type light curve. Additionally, we report
two RR-Lyrae ab and c types with ultralow amplitude.
Description:
We analyzed 255 light curves of giant stars from NGC-3201 in the V and
I bands to carry out this research. Of the total sample of 255 giant
stars, 88 targets were considered as candidates.
Objects:
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RA (2000) DE Designation(s)
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10 17 36.81 -46 24 44.9 NGC3201 = C 1015-461
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 46 24908 Time series for V and I filters of each star
table2.dat 77 88 Significance S values for V and I filters for 88
candidate variable stars and their classification
based on the criteria from Section 3.2.
table3.dat 97 18 Final parameters for all stars classified as
variable from the significance test
table4.dat 99 29 Final parameters for all stars classified as
possible variable and dubious from the
significance test
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See also:
II/183 : UBVRI Photometric Standards (Landolt 1992)
II/337 : VISTA Variables in the Via Lactea Survey DR1 (Saito+, 2012)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
II/376 : VISTA Variable in the Via Lactea Survey (VVV) DR4.2 (Minniti+, 2023)
VII/195 : Globular Clusters in the Milky Way (Harris, 1996)
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
J/A+A/505/139 : Abund of red giants in 17 globular clusters (Carretta+, 2009)
J/A+A/505/117 : Abund of red giants in 15 globular clusters (Carretta+, 2009)
J/MNRAS/413/1275 : VrI light curves of NGC6981 variables (Bramich+, 2011)
J/other/RMxAA/50.307 : RR Lyr light curves in NGC 3201 (Arellano Ferro+, 2014)
J/ApJ/801/69 : Fe EWs 21 giant star members of NGC3201 (Mucciarelli+, 2015)
J/AcA/66/31 : NGC 3201 variable stars in NGC 3201 (Kaluzny+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq [1/88] Sequential star identifier
4- 4 A1 --- Filt [VI] Filter
6- 22 F17.9 d HJD [2456371/2456375] Heliocentric Julian Date of
Observation
24- 31 F8.5 mag mag [10.7/82] Standard magnitude in Filt
33- 38 F6.4 mag e_mag [0.005/0.02] Uncertainty in mag
40- 46 F7.5 mag sigma [0.0002/0.009] Internal errors associated with
the DanDIA reduction program
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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- 2 I2 --- Seq [1/88] Sequential star identifier
4- 5 I2 h RAh [10] Hour of Right Ascension (J2000)
7- 8 I2 min RAm Minute of Right Ascension (J2000)
10- 15 F6.3 s RAs Second of Right Ascension (J2000)
17- 17 A1 --- DE- [-] Sign of the Declination (J2000)
18- 19 I2 deg DEd [46] Degree of Declination (J2000)
21- 22 I2 arcmin DEm Arcminute of Declination (J2000)
24- 28 F5.2 arcsec DEs Arcsecond of Declination (J2000)
30- 36 F7.3 --- SV [-13/16.6] Significance values for V filter
38- 44 F7.3 --- SI [-20/21] Significance values for I filter
46- 64 I19 --- Gaia ? Gaia DR3 identifier
66- 77 A12 --- Class Classification
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq [1/88] Sequential star identifier
4- 11 F8.5 mag Vmag [13.2/16] Mean V-band magnitude from light curves
13- 20 F8.5 mag Imag [11.8/15.4] Mean I-band magnitude from light curves
22- 28 F7.5 d PerV [0.14/0.59] V-band period, days
30- 36 F7.5 d e_PerV [0.00/0.006] Uncertainty in PerV
38- 44 F7.5 mag AVmag [0.00/0.8] Amplitude in V band
46- 52 F7.5 mag e_AVmag [0.00/0.03] Uncertainty in AVmag
54- 60 F7.5 d PerI [0.14/0.6] I-band period, days
62- 68 F7.5 d e_PerI [0.0007/0.008] Uncertainty in PerI
70- 76 F7.5 mag AImag [0.006/0.5] Amplitude in I band
78- 84 F7.5 mag e_AImag [0.0006/0.02] Uncertainty in AImag
86- 97 A12 --- Type Giant Type
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq [2/86] Sequential star identifier
4- 11 F8.5 mag Vmag [12.5/15.9] Mean Vband magnitude from light curves
13- 20 F8.5 mag Imag [11/14.7] Mean I-band magnitude from light curves
22- 29 F8.6 d PerV [0.14/0.75] V-band period, days
31- 37 F7.5 d e_PerV [0.0002/0.02] Uncertainty in PerV
39- 45 F7.5 mag AVmag [0.004/0.03] Amplitude in V band
47- 53 F7.5 mag e_AVmag [0.0006/0.002] Uncertainty in AVmag
55- 62 F8.6 d PerI [0.11/0.74] I-band period, days
64- 70 F7.5 d e_PerI [0.0003/0.02] Uncertainty in PerI
72- 78 F7.5 mag AImag [0.003/0.02] Amplitude in I band
80- 86 F7.5 mag e_AImag [0.0005/0.002] Uncertainty in AImag
88- 99 A12 --- Type Giant Type
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 18-Mar-2024