Possible young stellar objects in the region of the Cygnus OB2 (VI Cygni) association from IRAS observations

Abstract

Several massive young stellar objects are found from an analysis of the 12- to 100-micron flux data of IRAS sources in the region of the Cyg OB2 association. Sixty-four sources with positive spectral indices and steeply increasing FIR flux distribution similar to that found in known young stellar objects are identified. Some of these sources have massive cold dust shells with FIR luminosities of the order of 1000 to 10,000 solar luminosities and are most likely massive young stellar objects which may show bipolar structure and molecular outflows. The luminosity function for the IRAS sources in the Cyg OB2 suggests that most of the sources with positive spectral indices are most likely members of the Cyg OB2 association. It is suggested that there may be a few hundred low-mass young stellar objects in the Cyg OB2 association.