J/MNRAS/499/4026 NGC 6254 variable stars VI light curves (Arellano Ferro+, 2020)
The globular cluster M10: reassessment of stellar membership, distance,
and age using its variable and HB stars.
Arellano Ferro A., Yepez M.A., Muneer S., Bustos Fierro I.H.,
Schroder K.P., Giridhar S., Calderon J.H.
<Mon. Not. R. Astron. Soc., 499, 4026-4039 (2020)>
=2020MNRAS.499.4026A 2020MNRAS.499.4026A (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Photometry, VRI
Keywords: stars: evolution - stars: fundamental parameters -
stars: horizontal branch - stars: variables: RR Lyrae -
globular clusters: individual: (M10)
Abstract:
Time-series VI CCD photometry of the globular cluster M10 (NGC 6254)
is employed to perform a detailed identification, inspection of their
light curves, their classification and their cluster membership, of
all the known variables reported up to 2018. The membership analysis
is based on the Gaia-DR2 positions and proper motions. The metallicity
of the cluster is estimated based on the sole RRc star known in the
cluster. The Fourier decomposition of its light curve leads to
[Fe/H]ZW=-1.59±0.23dex. The mean cluster distance, estimated by
several independent methods is 5.0±0.3kpc. A multi-approach
search in a region of about 10x10arcmin2 around the cluster
revealed three new variables, one SX Phe (V35) and two sinusoidal
variables on the red giant branch of unclear classification (V36,V37).
Modelling the HB stars is very sensitive to the stellar hydrogen shell
mass, which surrounds the 0.50M☉ helium core. To match the full
stretch of the HB population, a range of total mass of 0.56 to
0.62M☉ is required. These models support a distance of 5.35kpc
and an age of about 13Gyrs, and hints to some individual variation of
the mass loss on the upper RGB, perhaps caused by the presence of
closed magnetic field in red giants.
Description:
The data used in this work were obtained from three sites. The first
set of data was obtained with the 0.84m telescope at the San Pedro
Mertir Observatory, (Baja California, Mexico), during 16
non-consecutive nights, between 2018 June 18th and 2019 July 01th. We
used a Spectral Instrument CCD of 1024x1024 pixels with a scale of
0.444arcsec/pix, translating to an FoV of approximately
7.57x7.57arcmin2. The second set of data was obtained at the Bosque
Alegre Astrophysical Station of the Cordoba Observatory, Universidad
Nacional de Cordoba, Argentina, with the 1.54-m telescope.
Observations were acquired during 5 non-consecutive nights between
2018 August 11th and 2019 September 02th. The detector in 2018 was a
CCD KAF-16803 of 4096x4096-pixels, and in 2019 a CCD KAF-6303E of
3072x2048-pixels. The FoV on the first CCD was 16.9x16.9-arcmin2,
and on the second one 12.6x8.4-arcmin2. In both seasons, the
detectors were binned 2x2 for a scale of 0.496arcsec/pix, and the
frames were trimmed to a maximum size of approximately 10arcmin2 in
order to avoid images severely affected by coma. The third set of data
was obtained using the 2m telescope at the Indian Astronomical
Observatory (IAO) in Hanle, India on 1 night on 2020 April 24th. 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 6254 (M10).
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 96 37 Data of variable stars in M10 in the FoV of
our images
table5.dat 50 25600 VI photometry of 42 variables in the field of
NGC 6254 (M10)
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- VName Variable name (V1-V37 and N3) (G1)
4 A1 --- n_VName [d] Note on Name (1)
6- 11 A6 --- VarType Variable type
14- 19 F6.3 mag <Vmag> ? Intensity-weighted mean V magnitude
20 A1 --- n_<Vmag> [i] i when <Vmag> is magnitude-weighted
mean V magnitude
22- 27 F6.3 mag <Imag> ? Intensity-weighted mean I magnitude
28 A1 --- n_<Imag> [i] i when <Imag> is magnitude-weighted
mean I magnitude
30- 34 F5.3 mag AV ? Amplitude in V band
36- 40 F5.3 mag AI ? Amplitude in I band
42- 49 F8.6 d Per ? This work period (2)
52- 60 F9.6 d Perl ? Period from Rozyczka et al.,
2018AcA....68..237R 2018AcA....68..237R
62- 70 F9.4 d HJDmax ? Time of maximum brightness (HJD-2459999)
72- 73 I2 h RAh Right ascension (J2000)
75- 76 I2 min RAm Right ascension (J2000)
78- 82 F5.2 s RAs Right ascension (J2000)
84 A1 --- DE- Declination sign (J2000)
85 I1 deg DEd Declination (J2000)
87- 88 I2 arcmin DEm Declination (J2000)
90- 94 F5.2 arcsec DEs Declination (J2000)
96 A1 --- Memb [YN?] Membership status (3)
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Note (1): d: Newly reported in this work.
Note (2): All light curves in Fig. 3 are phased with these periods. When our
data were scanty for a proper determination, the period from RO18 was adopted.
These periods should be preferred to the ones found in Section 7.
Note (3): Membership status as follows:
Y = member
N = no-member
? = no proper motion available
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
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): Simbad names:
V1-V16 : Cl* NGC 6254 SAW VNN
V17-V24 : [RNS2018] NGC 6254 VNN
V23, V30, V34
N3 : [RNS2018] N3
Acknowledgements:
Armando Arellano Ferro, armando(at)astro.unam.mx
References:
Rozyczka et al., 2018AcA....68..237R 2018AcA....68..237R
(End) A. Arellano Ferro [[IA-UNAM, Mexico], P. Vannier [CDS] 29-Nov-2020