J/A+A/542/A68 NGC 3231, 7055 and 7127 BVRI photometry (Paunzen+, 2012)
BVRI photometry of NGC 3231, NGC 7055, and NGC 7127.
Paunzen E., Hermansson L., Holmstroem P.
<Astron. Astrophys. 542, A68 (2012)>
=2012A&A...542A..68P 2012A&A...542A..68P
ADC_Keywords: Clusters, open ; Photometry, CCD ; Photometry, UBVRI
Keywords: open clusters and associations: general -
open clusters and associations: individual: NGC 3231 -
open clusters and associations: individual: NGC 7055 -
open clusters and associations: individual: NGC 7127
Abstract:
Open clusters are often used as tracers for the formation and
evolution of the Milky Way. But they can also be used to study
distinct "local stellar populations" and all kind of stellar groups.
All these studies crucially depend on their unambiguous detection and
classification separating them from the fore- and background field
population. Still more than one third of the catalogued galactic open
clusters are unstudied to date. We have chosen three northern open
cluster fields, namely NGC 3231, NGC 7055, and NGC 7127 which have
been never studied before to shed more light on their true nature. We
present Johnson-Cousins BVRI photometry down to V=19mag. After the
transformation to the standard systems, colour-magnitude diagrams were
generated. These diagrams were used to fit solar abundant isochrones
to determine the distance modulus, reddening and apparent age of the
main sequences. From the analysis of the colour-magnitude diagrams and
the available proper motions we conclude that NGC 7055 and NGC 7127
are young, real, open clusters. NGC 3231, on the other hand, is
probably a high galactic latitude open cluster remnant.
Description:
Photometric CCD BVRI measurements of objects within the open cluster
candidates NGC 3231, NGC 7055, and NGC 7127 were obtained at the
Sandvreten Observatory (Uppsala, Sweden).
Objects:
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RA (2000) DE Designation(s)
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10 27 29 +66 47 54 NGC 3231 = NGC 3231
21 19 30 +57 36 00 NGC 7055
21 43 41 +54 37 48 NGC 7127 = C 2142+543
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 69 39 Observed program stars of NGC 3231
table2.dat 69 251 Observed program stars of NGC 7055
table3.dat 69 288 Observed program stars of NGC 7127
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Byte-by-byte Description of file: table1.dat table2.dat table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Stars number sorted after X and Y,
within the cluster
5- 10 F6.2 pix Xpos X coordinate (scale 0.9"/pix)
12- 17 F6.2 pix Ypos Y coordinate (scale 0.9"/pix)
19- 24 F6.3 mag Bmag ?=- Johnson-Cousins B magnitude
26- 30 F5.3 mag e_Bmag ?=- Error in B magnitude
32- 37 F6.3 mag Vmag ?=- Johnson-Cousins V magnitude
39- 43 F5.3 mag e_Vmag ?=- Error in V magnitude
45- 50 F6.3 mag Rcmag ?=- Johnson-Cousins R magnitude
52- 56 F5.3 mag e_Rcmag ?=- Error in R magnitude
58- 63 F6.3 mag Icmag ?=- Johnson-Cousins I magnitude
65- 69 F5.3 mag e_Icmag ?=- Error in I magnitude
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Acknowledgements:
Ernst Paunzen, epaunzen(at)physics.muni.cz
(End) Patricia Vannier [CDS] 04-Jun-2012