J/AJ/145/7 UBVRI CCD photometry of the open cluster NGC 6811 (Janes+, 2013)
NGC 6811: an intermediate-age cluster in the Kepler field.
Janes K., Barnes S.A., Meibom S., Hoq S.
<Astron. J., 145, 7 (2013)>
=2013AJ....145....7J 2013AJ....145....7J
ADC_Keywords: Clusters, open ; Photometry, UBVRI ; Photometry, CCD
Keywords: Hertzsprung-Russell and C-M diagrams - methods: data analysis -
open clusters and associations: individual: NGC 6811
Abstract:
NGC 6811 is one of the four open clusters located in the Kepler
spacecraft field of view. We obtained UBVRI photometry of the cluster
on six nights (four of them photometric) with the 1.08m Hall and 1.83m
Perkins telescopes at Lowell Observatory. The mean photometric
precision ranges from better than 0.01mag in the V, B-V, V-R, and V-I
indices among stars brighter than magnitude 15 to about 0.05mag for
U-B at magnitude 18. We followed a Bayesian statistical approach using
the Markov Chain Monte Carlo algorithm to determine the cluster
reddening, distance, age, and iron content from a maximum-likelihood
fit to stellar isochrones. Using the Yale-Yonsei isochrones, we
derived E(B-V)=0.066±0.025, (m-M)V=10.13±0.19,
age=1.06±0.19Gyr, and Z=0.012±0.004 ([Fe/H]=-0.18); with the
Padova isochrones, we found E(B-V)=0.081±0.015,
(m-M)V=10.31±0.11, age=0.94±0.08Gyr, and Z=0.012±0.002
([Fe/H]=-0.20). The uncertainties include possible errors in the
photometric zero points of ±0.01mag, but do not include
uncertainties in the models. Taking into account the differences
between the two sets of models, we find the best estimate for the
cluster parameters to be E(B-V)=0.074±0.024, (m-M)V=10.22±0.18,
age=1.00±0.17Gyr, and Z=0.012±0.004 ([Fe/H]=-0.19).
Description:
We obtained CCD images of NGC 6811 at Lowell Observatory using the
Hall 1.2m telescope on 2005 Sep 30 (SITe CCD detector, and B, V, I
filters), on 2005 Oct 2 (SITe CCD detector, and B filter), and on 2010
Sep 17-18 (e2v CCD detector, and U, B, V filters), and with the
Perkins 1.8m telescope on 2009 Sep 21 (Fairchild CCD detector, and B,
V, R, I filters), and on 2011 Jun 27 (e2v CCD detector, and B, V
filters).
Objects:
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RA (2000) DE Designation(s)
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19 37 17 +46 23.3 NGC 6811 = Cl Melotte 222
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 103 10674 Photometric catalog in NGC 6811
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/other/RMxAA/47.309 : NGC 6811 & NGC 6830 uvby-β photometry (Pena+, 2011)
J/AJ/142/112 : KIC photometric calibration (Brown+, 2011)
J/ApJ/733/L9 : Stellar rotation for 71 NGC 6811 members (Meibom+, 2011)
J/AJ/136/118 : Open clusters as galactic disk tracers. I. (Frinchaboy+, 2008)
J/A+A/438/1163 : Catalogue of Open Cluster Data (COCD) (Kharchenko+, 2005)
J/PAZh/25/115 : A study of the open cluster NGC 6811 (Glushkova+, 1999)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Star [1/10674] Running star number (in RA order)
<[JBM2013] NNNNN> in Simbad
7- 14 F8.2 arcsec Xpos [-1288/1753] X position (X=αcosδ) (1)
16- 23 F8.2 arcsec Ypos [-1261.1/1853.01] Y position (Y=δ) (1)
25- 30 F6.3 mag Vmag [10.37/22.891] The V band magnitude
32- 36 F5.3 mag e_Vmag Error in Vmag
38- 43 F6.3 mag B-V [-0.232/1.851]?=99.999 The (B-V) color index
45- 49 F5.3 mag e_B-V ?=9.999 Error in B-V
51- 56 F6.3 mag U-B [-1.04/2.194]?=99.999 The (U-B) color index
58- 62 F5.3 mag e_U-B ?=9.999 Error in U-B
64- 69 F6.3 mag V-R [0.012/1.438]?=99.999 The (V-R) color
71- 75 F5.3 mag e_V-R ?=9.999 Error in V-R
77- 82 F6.3 mag V-I [-0.141/3.192]?=99.999 The (V-I) color
84- 88 F5.3 mag e_V-I ?=9.999 Error in V-I
90- 91 I2 --- NU [0/13] Number of U band frames
93- 94 I2 --- NB [0/25] Number of B band frames
96- 97 I2 --- NV [3/25] Number of V band frames
99-100 I2 --- NR [0/6] Number of R band frames
102-103 I2 --- NI [0/8] Number of I band frames
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Note (1): For matching stars, we used stars from the Kepler Input Catalog (KIC;
Brown et al., 2011, cat. J/AJ/142/112) to transform the individual images
to a common coordinate system, centered on the cluster center at
19:37:17+46:23:18 (J2000)
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History:
From electronic version of the journal
References:
Janes et al., Paper II, 2014AJ....147..139J 2014AJ....147..139J, cat. J/AJ/147/139
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 19-Feb-2014