The young stellar cluster associated with IRAS 09149-4743

¹ Escola de Artes, Ciências e Humanidades, USP, Av. Arlindo Bettio, 1000, 03828-000, São Paulo, SP, Brazil e-mail: ortiz@astro.iag.usp.br
² Departamento de Astronomia, IAG/USP, Rua do Matão, 1226, Cidade Universitária, 05508-900, São Paulo, SP, Brazil

Received: 10 November 2005
Accepted: 20 August 2006

Abstract

Context.We present the results of a near-infrared survey of the young stellar cluster associated with IRAS 09149-4743, a member of the Vela Molecular Ridge.

Aims.The main purpose of this survey is to study the cluster members and find the ionizing sources of the associated HII region.

Methods.Infrared photometry of 62 stars located in the crowded parts of the cluster is given in the J, H, and K bands. Colour–colour and colour–magnitude diagrams are drawn to obtain an estimate of their spectral type and reddening.

Results.Three main sources are identified as candidates to ionize the HII region: a star located at the centre of the cluster, inside the IRAS error ellipse; a second star, member of a small “subcluster” situated 1.1' to the southeast of the former; and a third object, showing very high colour indices, which indicate visual extinction over 20 mag. Dereddened J magnitudes suggest that the former two stars probably are the main ionizing sources, whereas the latter is too reddened to allow a reliable estimate of its spectral type by photometric methods.