| Issue |
Astron. Astrophys. Suppl. Ser.
Volume 127, Number 3, February I 1998
|
|
|---|---|---|
| Page(s) | 423 - 432 | |
| DOI | https://doi.org/10.1051/aas:1998111 | |
| Published online | 15 February 1998 | |
Fundamental parameters of the highly reddened young open clusters Westerlund 1 and 2 *,**
1
Observatorio Astronómico, Universidad Nacional de Córdoba, Laprida 854, 5000 Córdoba, Argentina
2
Instituto de Física, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil
Send offprint request to: A.E. Piatti
Received:
2
April
1997
Accepted:
23
May
1997
We study the compact open clusters Westerlund 1 (BH 197) and Westerlund 2.
We present CCD integrated spectroscopy for both clusters, and CCD
imaging in the V and I bands for the former one. So far, Westerlund 1
is possibly the most reddened open cluster studied in detail
(
). It has an age of 8 ± 3 Myr
and a distance from the Sun of 
kpc. For
Westerlund 2 we derive a visual absorption 
mag, an age of 2-3 Myr, and
kpc. From luminosity and structural arguments
we conclude that Westerlund 1, although young and compact, it is a
massive cluster, in contrast to Westerlund 2.
Key words: open clusters: individual: Westerlund 1, Westerlund 2 / open clusters: general
Based on observations made at Complejo Astronómico El Leoncito, which is operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the Universities of La Plata, Córdoba and San Juan, Argentina, and at the University of Toronto (David Dunlap Observatory) 24-inch telescope, Las Campanas, Chile.
© European Southern Observatory (ESO), 1998