Resumen
The distance to the Lambda Orionis Star Forming Region (LOSFR) is 400 pc (Murdin & Perston 1977). There are 11 B stars around the 1 Ori 08 III star, which is exciting a HII region named S 264. Zhang et al. (1989) detected with IRAS a dust ring (diameter of 9 deg) centered around this star. Two dark clouds, Barnard 30 and 35 (B30 and B35) are located within this ring. The structure of the complex is illustrated by Figure 1, where we display a IRAS image taken at 12 microns. Based on a H α emission survey, Duerr, Imhoff & Lada (1982), identified three stellar clusters centered around 1 Ori (Collinder 69) and the dark clouds B30 and B35. Dolan & Mathieu (1999, 2001, 2002, =D&M) collected deeper photometry (VRI filters) in an area about 8 sq.deg. centered on the OB association, discovering a significant population of low mass stellar members, and obtained medium resolution multifiber spectroscopy for those candidates closest to the central star. According to them, the turn-off age for the massive stars is ~ 6 Myr.
