NEW YOUNG STELLAR OBJECT CANDIDATES IN THE CHAMELEON-I MOLECULAR CLOUD DISCOVERED BY DENIS

We present an analysis of point sources discovered by DENIS in an area of approximate to 1(.)(degrees)5 x 3(.)(degrees) around the Chamaeleo n I molecular cloud. Most of the 30 000 objects detected in the J band are background stars that were previously used to derive an accurate extinction map of the full area (Cambresy et al., 1997) using star cou nts. Here, we investigate the young stellar population of the cloud us ing the IJK(s) photometric DENIS data. The whole sample of 126 already known YSOs, which are mainly T Tauri stars, are identified in the DEN IS catalogue. Besides, we propose 54 sources as new candidates of YSOs . These new faint objects are selected according to their extremely re d near infrared colour, that cannot be explained only by the reddening of the cloud. Moreover they are concentrated near the most obscured a reas of the cloud. Pending spectroscopic measurements, the sources are interpreted as probable classical T Tauri stars that have escaped pre vious spectroscopic, IRAS or X-ray observations and pertaining to the low-end of the luminosity function. Assuming that they are reliable YS Os with massive accretion disks, and using theoretical pre-main-sequen ce tracks we estimate the age of this sample to be ranging from 5 10(5 ) to 4 10(6) years, an elapse of time that spans the range between the end of the star formation in the cloud and the maximum life time of t he circumstellar disk.