J/A+A/370/931 BVI photometry of 4 open clusters (Piatti+, 2001)
On the stellar content of the open clusters Melotte 105, Hogg 15, Pismis 21 and
Ruprecht 140
Piatti A.E., Claria J.J.
<Astron. Astrophys. 370, 931 (2001)>
=2001A&A...370..931P 2001A&A...370..931P
ADC_Keywords: Clusters, open ; Photometry, CCD ; Photometry, UBVRI
Keywords: open clusters: individual: Melotte 105, Hogg 15, Pismis 21,
Ruprecht 140 - open clusters: general - techniques: photometric
Abstract:
CCD observations in the B, V and I passbands have been used to
generate colour-magnitude diagrams reaching down to V∼19mag for two
slightly characterized (Melotte 105 and Hogg 15) and two almost
unstudied (Pismis 21 and Ruprecht 140) open clusters. The sample
consists of about 1300 stars observed in fields of about 4'x4'. Our
analysis shows that neither Pismis 21 nor Ruprecht 140 are genuine
open clusters since no clear main sequences or other meaningful
features can be seen in their colour-magnitude diagrams. Melotte 105
and Hogg 15 are open clusters affected by E(B-V)=0.42±0.03 and
0.95±0.05, respectively. Their distances to the Sun have been
estimated as 2.2±0.3 and 2.6±0.08kpc, respectively, while the
corresponding ages estimated from empirical isochrones fitted to the
Main Sequence cluster members are ∼350Myr and 300Myr, respectively.
The present data are not consistent with the membership of the WN6
star HDE 311884 to Hogg 15.
Objects:
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RA (2000) DE Designation(s)
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11 19 30. -63 30 00 Cl Melotte 105
12 43 36. -63 06 00 Cl Hogg 15
15 16 48. -59 39 00 Cl Pismis 21
18 21 51.7 -33 08 42 Cl Ruprecht 140
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 72 356 Magnitudes and colours of stars in the field
of Melotte 105
table3.dat 72 233 Magnitudes and colours of stars in the field
of Hogg 15.
table4.dat 72 343 Magnitudes and colours of stars in the field
of Pismis 21.
table5.dat 72 259 Magnitudes and colours of stars in the field
of Ruprecht 140.
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See also:
J/A+A/360/529 : Pismis 22, NGC 6178, NGC 6216, Ruprecht 130 (Piatti+, 2000)
J/ApJS/116/263 : VI photometry of open clusters (Piatti+ 1998)
Byte-by-byte Description of file: table?.dat
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Bytes Format Units Label Explanations
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4- 6 I3 --- ID Star number
8- 14 F7.3 pix Xpos X coordinate (1)
17- 23 F7.3 pix Ypos Y coordinate (1)
26- 31 F6.3 mag Vmag V magnitude
34- 38 F5.3 mag e_Vmag rms uncertainty on Vmag
41- 46 F6.3 mag B-V ?=9.999 B-V colour index
49- 53 F5.3 mag e_B-V ?=9.999 rms uncertainty on B-V
56- 61 F6.3 mag V-I V-I colour index
64- 68 F5.3 mag e_V-I rms uncertainty on V-I
72 I1 --- o_Vmag Number of measurements
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Note (1): 1 pix = 0.45". North is up and East is to the left.
For Ruprecht 140, the adopted center is (x, y) ∼ (350, 100)
For Hogg 15, the adopted center is (x, y) ∼ (380, 230)
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Acknowledgements:
Andres Piatti
(End) Patricia Bauer [CDS] 27-Apr-2001