J/A+A/372/95 NGC 2439 ubvyβ photometry (Kaltcheva+, 2001)
The association surrounding NGC 2439
Kaltcheva N.T., Gredel R., Fabricius C.
<Astron. Astrophys. 372, 95 (2001)>
=2001A&A...372...95K 2001A&A...372...95K
ADC_Keywords: Photometry, uvby, beta ; Stars, early-type
Keywords: stars: early type - stars: fundamental parameters -
open clusters and associations: individual: NGC 2439 - ISM: clouds
Abstract:
The structure of the field surrounding the Galactic cluster NGC 2439
is studied utilizing uvbyβ photometry of bright OB stars. We
collate all photometric and kinematic data available to identify
possible groupings. The stars of our sample show a large scatter in
their distances, radial velocities, proper motions and reddenings. We
conclude that they do not belong to a single stellar association. We
find evidence of the existence of three coherent structures at
distances of 370pc, 1kpc, and 2.6-3.2kpc. The high stellar density
toward NGC 2439 is very likely due to a decreased absorption in this
direction, which poses some doubt on the reality of the cluster. A
comprehensive uvbyβ study of NGC 2439 is required to clarify its
nature. The spatial distribution of the stars and their reddening are
used to characterise the spatial distribution of the visual extinction
in the region. The results obtained confirm previously determined
constraints on the formation mechanism of interstellar CH+ towards
the NGC 2439 field.
Objects:
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RA (2000) DE Designation(s)
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07 40 48 -31 39.0 NGC 2439
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 157 56 NGC 2439 photometric data and derived quantities
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See also:
III/135 : Henry Draper Catalogue and Extension (Cannon+ 1918-1924; ADC 1989)
I/108 : Cape Photographic Durchmusterung (Gill+ 1895-1900)
III/43 : Luminous Stars in the Southern Milky Way (Stephenson+ 1971)
I/193 : Positions and Proper Motions - South (Bastian+ 1993)
II/215 : uvby-beta Catalogue (Hauck+ 1997)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- HD ? HD (Cat. III/135) number
7- 13 I7 --- CPD ? CPD (Cat. I/108)number
15- 17 I3 --- LS ? LS (Cat. III/43)number
19- 24 I6 --- PPM ? PPM (Cat. I/193)number
26- 28 A3 --- Group ? Possible membership to a group (1)
30- 35 F6.2 deg GLON Galactic longitude
37- 41 F5.2 deg GLAT Galactic latitude
43- 54 A12 --- SpType MK classification
56- 61 F6.3 mag Vmag ? standard Johnson V magnitude
63- 68 F6.3 mag b-y ? Stroemgren b-y index
70- 75 F6.3 mag m1 ? Stroemgren m1 index
77- 82 F6.3 mag c1 ? Stroemgren c1 index
84- 88 F5.3 mag beta ? Hβ index
90- 95 A6 --- Source ? Source of the photometric data (2)
97-102 F6.3 mag (b-y)0 ? Stroemgren b-y index corrected for reddening
104-108 F5.3 mag m0 ? Stroemgren m1 index corrected for reddening
110-115 F6.3 mag c0 ? Stroemgren c1 index corrected for reddening
117-121 F5.3 mag E(b-y) ? Colour excess E(b-y)
123-127 F5.3 mag Vmag0 ? Standard Johnson V magnitude corrected for
reddening
129-133 F5.3 mag beta(c0) ? Hβ index calculated from c0
135-139 F5.2 mag VMAG ? Absolute V magnitude
140 A1 --- u_VMAG Uncertainty flag on VMAG
142-145 I4 pc r ? Distance
146 A1 --- u_r Uncertainty flag on r
148-151 F4.1 km/s RV ? Radial velocity
152 A1 --- --- [/]
153-154 I2 km/s RV2 ? Second radial velocity value (when variable)
155 A1 --- --- [/]
156-157 I2 km/s RV3 ? Third radial velocity value (when variable)
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Note (1): Possible membership to a group:
H: Humphreys 1976
b: Bochum 15
N: NGC 2439 No2
Cr: Collinder 140
Note (2): Source of the photometric data:
HM: Hauck & Mermilliod, Cat. II/215
KGF: This paper, table 1
KO: Kaltcheva & Olsen, 1999A&A...352..600K 1999A&A...352..600K
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Acknowledgements: Nadia Kaltcheva
(End) Patricia Bauer [CDS] 28-May-2001