A photometric study of the young open cluster NGC 1220 ^*,**

¹ Dipartimento di Astronomia, Università di Padova, Vicolo Osservatorio 2, 35122 Padova, Italy e-mail: ortolani@pd.astro.it
² Osservatorio Astronomico di Milano, Italy e-mail: covino@merate.mi.astro.it
³ Universidade Federal do Rio Grande do Sul, Dept. de Astronomia, CP 15051, Porto Alegre 91501-970, Brazil e-mail: bica@if.ufrgs.br
⁴ Universidade de Sao Paulo, Dept. de Astronomia, CP 3386, Sao Paulo 01060-970, Brazil e-mail: barbuy@astro.iag.usp.br

Corresponding author: G. Carraro, giovanni.carraro@unipd.it

Received: 9 April 2002
Accepted: 27 May 2002

Abstract

We present UBV CCD observations obtained in the field of the northern open cluster NGC 1220, for which little information is available. We provide also BV CCD photometry of a field 5′ northward of NGC 1220 to take into account field star contamination. We argue that NGC 1220 is a young compact open cluster, for which we estimate a core radius in the range  arcmin. We identify 26 likely candidate members with spectral type earlier than , down to mag on the basis of the position in the two-colour Diagram and in the Colour Magnitude Diagrams (CMDs). By analyzing the distribution of these stars in the colour-colour and CMDs, we find that NGC 1220 has a reddening  mag, is placed pc distant from the Sun, and has an age of about 60 Myrs. The cluster turns out to be located about 120 pc above the Galactic plane, relatively high with respect to its age.