Luminosity and Mass Function of the Galactic open cluster NGC 2422^*

¹ Dipartimento di Scienze Fisiche ed Astronomiche, Università di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy
² INAF - Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy
³ Astrophysics Division - Space Science Department of ESA, ESTEC, Postbus 299, 2200 AG Noordwijk, The Netherlands

Corresponding author: L. Prisinzano, loredana@oapa.astropa.unipa.it

Received: 6 May 2002
Accepted: 6 April 2003

Abstract

We present UBVRI photometry of the open cluster NGC 2422 (age yr) down to a limiting magnitude . These data are used to derive the Luminosity and Mass Functions and to study the cluster spatial distribution. By considering the color–magnitude diagram data and adopting a representative cluster main sequence, we obtained a list of candidate cluster members based on a photometric criterion. Using a reference field region and an iterative procedure, a correction for contaminating field stars has been derived in order to obtain the Luminosity and the Mass Functions in the range. By fitting the spatial distribution, we infer that a non-negligible number of cluster stars lies outside our investigated region. We have estimated a correction to the Mass Function of the cluster in order to take into account the “missing” cluster stars. The Present Day Mass Function of NGC 2422 can be represented by a power-law of index (rms) – the Salpeter Mass Function in this notation has index  – in the mass range . The index α and the total mass of the cluster are very similar to those of the Pleiades.