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A&A Supplement series, Vol. 127, February I 1997, 423-432

Received April 2; accepted May 23, 1997

Fundamental parameters of the highly reddened young open clusters Westerlund 1 and 2gif,gif

A.E. Piattitex2html_wrap1409 - E. Bicatex2html_wrap1411 - J.J. Clariátex2html_wrap1409

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tex2html_wrap1415  Observatorio Astronómico, Universidad Nacional de Córdoba, Laprida 854, 5000 Córdoba, Argentina
tex2html_wrap1417  Instituto de Fısica, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil


We study the compact open clusters Westerlund1 (BH197) and Westerlund2. We present CCD integrated spectroscopy for both clusters, and CCD imaging in the V and I bands for the former one. So far, Westerlund1 is possibly the most reddened open cluster studied in detail (tex2html_wrap_inline1393). It has an age of 8 tex2html_wrap_inline1395 3 Myr and a distance from the Sun of tex2html_wrap_inline1397 kpc. For Westerlund2 we derive a visual absorption tex2html_wrap_inline1399 mag, an age of 2-3 Myr, and tex2html_wrap_inline1403 kpc. From luminosity and structural arguments we conclude that Westerlund1, although young and compact, it is a massive cluster, in contrast to Westerlund2.

keywords: open clusters: individual: Westerlund1, Westerlund2 -- open clusters: general

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