J/AJ/152/129 VR photometry for 914 stars in NGC 188 (Chen+, 2016)
Physical parameter study of eight W Ursae Majoris-type contact binaries in
NGC 188.
Chen X., Deng L., de Grijs R., Zhang X., Xin Y., Wang K., Luo C., Yan Z.,
Tian J., Sun J., Liu Q., Zhou Q., Luo Z.
<Astron. J., 152, 129-129 (2016)>
=2016AJ....152..129C 2016AJ....152..129C (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Photometry, VRI ; Radial velocities ;
Proper motions
Keywords: binaries: eclipsing - methods: data analysis -
open clusters and associations: individual: NGC 188, Berkeley 39 -
stars: distances
Abstract:
We used the newly commissioned 50cm Binocular Network telescope at
Qinghai Station of Purple Mountain Observatory (Chinese Academy of
Sciences) to observe the old open cluster NGC188 in V and R as part of
a search for variable objects. Our time-series data span a total of 36
days. Radial velocity and proper-motion selection resulted in a sample
of 532 genuine cluster members. Isochrone fitting was applied to the
cleaned cluster sequence, yielding a distance modulus of
(m-M)V0=11.35±0.10mag and a total foreground reddening of
E(V-R)=0.062±0.002mag. Light-curve solutions were obtained for eight
W Ursae Majoris eclipsing binary systems (W UMas), and their orbital
parameters were estimated. Using the latter parameters, we estimate a
distance to the W UMas that is independent of the host cluster's
physical properties. Based on combined fits to six of the W UMas (EP
Cep, EQ Cep, ES Cep, V369 Cep, and-for the first time-V370 Cep and
V782 Cep), we obtain an average distance modulus of
(m-M)V0=11.31±0.08mag, which is comparable to that resulting
from our isochrone fits. These six W UMas exhibit an obvious
period-luminosity relation. We derive more accurate physical
parameters for the W UMa systems and discuss their initial masses and
ages. The former show that these W UMa systems have likely undergone
angular momentum evolution within a convective envelope (W-type
evolution). The ages of the W UMa systems agree well with the
cluster's age.
Description:
We observed the open cluster NGC188 for a total of 36 nights during
two separate periods (2014 September 28-October 7: 2014 Sep 28, 2014
Oct 01, 2014 Oct 02, 2014 Oct 04, 2014 Oct 05, 2014 Oct 07; and 2016
January 13-March 10: 2016 Jan 13, 2016 Jan 14, 2016 Jan 15, 2016 Jan
20, 2016 Jan 22, 2016 Jan 23, 2016 Jan 25, 2016 Jan 26, 2016 Jan 27,
2016 Jan 28, 2016 Jan 29, 2016 Jan 30, 2016 Feb 02, 2016 Feb 03, 2016
Feb 04, 2016 Feb 05, 2016 Feb 06, 2016 Feb 07, 2016 Feb 09, 2016 Feb
14, 2016 Feb 17, 2016 Feb 19, 2016 Feb 22, 2016 Feb 24, 2016 Feb 25,
2016 Feb 27, 2016 Feb 28, 2016 Feb 29, 2016 Mar 05, 2016 Mar 07) using
the 50cm Binocular Network telescope (50BiN) at the Qinghai Station of
Purple Mountain Observatory (Chinese Academy of Sciences). The
time-series light-curve observations in the Johnson V and R bands were
obtained simultaneously using two Andor 2k*2k CCDs. The telescope's
field of view is 20*20arcmin2, which is adequate for covering the
central region of NGC188.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 69 914 Information for stars in the open cluster
NGC 188 field
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See also:
B/ocl : Optically visible open clusters and Candidates (Dias+ 2002-2015)
J/AJ/147/42 : V light curves of EP Cep, ES Cep, and V369 Cep (Zhu+, 2014)
J/AJ/137/5086 : NGC 188 V12 VI light curves (Meibom+, 2009)
J/AJ/137/3743 : Spectroscopic binary orbits in NGC 188 (Geller+, 2009)
J/AJ/135/2264 : Stellar radial velocities in NGC 188 (Geller+, 2008)
J/AJ/133/1409 : u'g'r'i'z' photometry in NGC 188 (Fornal+, 2007)
J/AJ/131/1565 : UBVI photometry of Berkeley 17 and NGC 188 (Krusberg+, 2006)
J/A+A/438/291 : X-ray sources in NGC 188 (Gondoin+, 2005)
J/PASP/116/1012 : A star catalog for the open cluster NGC 188 (Stetson+, 2004)
J/AJ/126/2922 : Astrometry and membership in NGC 188 (Platais+, 2003)
J/AJ/124/601 : Positions and proper motions in NGC 188 (Platais+, 2002)
J/A+A/390/961 : VI photometry in NGC 188 (Andreuzzi+, 2002)
J/AJ/118/2894 : UBVRI CCD photometry in NGC 188 (Sarajedini+, 1999)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 F7.4 deg RAdeg Right Ascension in decimal degrees (J2000)
9- 15 F7.4 deg DEdeg Declination in decimal degrees (J2000)
17- 23 F7.4 mag Vmag [11.8/19.2] Johnson V band magnitude (1)
25- 30 F6.4 mag e_Vmag [0.0025/0.22] Uncertainty in Vmag
32- 38 F7.4 mag Rmag [11.37/18.31] Cousins R band magnitude (1)
40- 45 F6.4 mag e_Rmag [0.0023/0.22] Uncertainty in Rmag
47- 52 F6.2 mas/yr pmRA [-28.2/48.3] Proper motion along RA (2)
54- 59 F6.2 mas/yr pmDE [-27/50.8] Proper motion along DE (2)
61- 67 F7.2 km/s RV [-306.7/45.4]?=0 Radial velocity (3)
69 I1 --- Mm [0/1] Membership code (1=cluster member, or
0=not a cluster member)
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Note (1): The V and R magnitudes are the 50cm Binocular Network telescope
(50BiN) photometry data.
Note (2): From Platais et al. 2003 (Cat. J/AJ/126/2922).
Note (3): From Geller et al. 2008 (Cat. J/AJ/135/2264).
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 09-Jan-2017