Hα emission-line stars in molecular clouds II. The M42 region

• We present a deep survey of H α  emission-line stars in the M 42 region using wide-field objective prism films. A total of 1699 H α emission-line stars were identified, of which 1025 were previously unknown, within an area of 5.̊5 × 5.̊5 centred on the Trapezium Cluster. We present H α  strength estimates, positions, and  JH K s  photometry extracted from 2MASS, and comparisons to previous surveys. The spatial distribution of the bulk of the stars follows the molecular cloud as seen in CO and these stars are likely to belong to the very young population of stars associated with the Orion Nebula Cluster. Additionally, there is a scattered population of H α  emission-line stars distributed all over the region surveyed, which may consist partly of foreground stars associated with the young NGC 1980 cluster, as well as some foreground and background dMe or Be stars. The present catalogue adds a large number of candidate low-mass young stars belonging to the Orion population, selected independently of their infrared excess or X-ray emission.

Ämnesord

Natural Sciences  (hsv)

Physical Sciences  (hsv)

Astronomy, Astrophysics and Cosmology  (hsv)

Naturvetenskap  (hsv)

Fysik  (hsv)

Astronomi, astrofysik och kosmologi  (hsv)

Astronomy with specialization in Astrophysics  (uu)

Astronomi med intiktning mot astrofysik  (uu)

Nyckelord

stars: emission-line

Be / stars: formation / stars: pre-main sequence