J/AJ/141/92 BVI photometry of 10 distant open clusters (Janes+, 2011)
A quantitative analysis of distant open clusters.
Janes K.A., Hoq S.
<Astron. J., 141, 92 (2011)>
=2011AJ....141...92J 2011AJ....141...92J
ADC_Keywords: Clusters, open ; Photometry, UBVRI
Keywords: Hertzsprung-Russell and C-M diagrams -
open clusters and associations: general -
open clusters and associations: individual (Berkeley 19, Berkeley 44,
King 25, NGC 6802, NGC 6827, Berkeley 52, Berkeley 56, NGC 7142,
NGC 7245, King 9) - techniques: photometric
Abstract:
The oldest open star clusters are important for tracing the history of
the Galactic disk, but many of the more distant clusters are heavily
reddened and projected against the rich stellar background of the
Galaxy. We have undertaken an investigation of several distant
clusters (Berkeley 19, Berkeley 44, King 25, NGC 6802, NGC 6827,
Berkeley 52, Berkeley 56, NGC 7142, NGC 7245, and King 9) to develop
procedures for separating probable cluster members from the background
field. We next created a simple quantitative approach for finding
approximate cluster distances, reddenings, and ages. We first conclude
that with the possible exception of King 25 they are probably all
physical clusters.
Description:
We made all of our observations using the PRISM (Perkins Re-Imaging
System) camera on the Perkins telescope. The PRISM instrument converts
the f/17.5 focal ratio of the telescope to f/4.45, with a
13.3x13.3-arcmin field of view and 15um (0.39-arcsec) pixel scale. We
used a standard Lowell Observatory BVRI filter set, designed to be
compatible with the Landolt standard stars. The seeing ranged from
about 1.5 to 2.5-arcsec, FWHM.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 74 10 Summary information for the target clusters
table9.dat 79 68222 Photometric catalog
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Cluster Cluster name
13- 14 I2 h RA1h Cluster right ascension (J2000)
16- 17 I2 min RA1m Cluster right ascension (J2000)
19- 20 I2 s RA1s Cluster right ascension (J2000)
22 A1 --- DE1- Cluster declination sign (J2000)
23- 24 I2 deg DE1d Cluster declination (J2000)
26- 27 I2 arcmin DE1m Cluster declination (J2000)
29- 30 I2 arcsec DE1s Cluster declination (J2000)
32- 34 I3 deg GLON Galactic longitude
36- 38 I3 deg GLAT Galactic latitude
40- 42 I3 arcsec Rad Radius
44- 50 A7 --- Name Name of the cluster, as in table9
52- 53 I2 h RAh Right ascension origin (J2000) (1)
55- 56 I2 min RAm Right ascension origin (J2000) (1)
58- 62 F5.2 s RAs Right ascension origin (J2000) (1)
64 A1 --- DE- Declination sign origin (J2000) (1)
65- 66 I2 deg DEd Declination origin (J2000) (1)
68- 69 I2 arcmin DEm Declination origin (J2000) (1)
71- 74 F4.1 arcsec DEs Declination origin (J2000) (1)
--------------------------------------------------------------------------------
Note (1): position of the origin of the (Xpos,Ypos) offsets in table9
(computed at CDS, not in the original data)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Name Cluster name
9- 13 I5 --- Star Running star number within a cluster
15- 21 F7.2 arcsec Xpos X (RA) position relative to cluster center (1)
23- 29 F7.2 arcsec Ypos Y (Dec) position relative to cluster center (1)
31- 36 F6.3 mag Vmag V band magnitude
38- 42 F5.3 mag e_Vmag Error in Vmag
44- 49 F6.3 mag B-V ?=99.999 The (B-V) color index (2)
51- 55 F5.3 mag e_B-V ?=9.999 Error in B-V (2)
57- 62 F6.3 mag V-I ?=99.999 The (V-I) color index (2)
64- 68 F5.3 mag e_V-I ?=9.999 Error in V-I (2)
70- 71 I2 --- nV [0/31] Number of frames in the V filter
73- 74 I2 --- nB [4/36] Number of frames in the B filter
76- 77 I2 --- nI [0/42] Number of frames in the I filter
79 A1 --- Mm [mnfx] Membership flag (3)
--------------------------------------------------------------------------------
Note (1): See Table 1 for cluster centers.
Note (2): Values of 99.999 and 9.999 indicate no data for that entry.
Note (3): Date type flag as follows:
m = possible cluster member
n = likely non-member
f = field star outside the cluster area
x = membership undetermined (NGC 7142 only)
--------------------------------------------------------------------------------
History:
* 01-Aug-2012: From electronic version of the journal
* 23-Jun-2013: added accurate positions in table1 at CDS, to give
a correct position of the stars in table9.
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 01-Aug-2012