Issue |
A&A
Volume 433, Number 3, April III 2005
|
|
---|---|---|
Page(s) | 931 - 940 | |
Section | Galactic structure, stellar clusters, and populations | |
DOI | https://doi.org/10.1051/0004-6361:20042240 | |
Published online | 29 March 2005 |
A low-absorption disk zone at low Galactic latitude in Centaurus
Universidade Federal do Rio Grande do Sul, Instituto de Física, CP 15051, Porto Alegre 91501-970, RS, Brazil e-mail: charles@if.ufrgs.br
Received:
22
October
2004
Accepted:
15
December
2004
We investigate the properties of two stellar concentrations in a low-absorption
disk zone in Centaurus, located respectively at ,
,
and
,
. The present analysis is based mostly on
2MASS photometry, as well as optical photometry. Based on colour–magnitude diagrams and
stellar radial density profiles, we show that these concentrations are not open star
clusters. Instead, they appear to be field stars seen through a differentially-reddened
window. We estimate that the bulk of the stars in both stellar concentrations is located at
~1.5 kpc from the Sun, a distance consistent with that of the Sgr-Car arm in that
direction. This low-absorption window allows one to probe into distant parts of the disk
besides the Sgr-Car arm, probably the tangent part of the Sct-Cru arm, and/or the far side
of the Sgr-Car arm in that direction. The main sequence associated to the Sgr-Car arm is
reddened by
, so that this window through the disk is comparable in reddening to
Baade's window to the bulge. We also investigate the nature of the open cluster candidate
Ru 166. The presently available data do not allow us to conclude whether Ru 166 is an
actual open cluster or field stars seen through a small-scale low-absorption window.
Key words: Galaxy: structure / Galaxy: stellar content
© ESO, 2005
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