A Detailed Study of G173.58+2.45: an Intermediate‐Mass Star‐forming Region

Abstract

The G173.58+2.45 outflow was imaged in CO line emission, millimeter and centimeter continuum emission, and near-infrared emission. The observations provide evidence that the outflow is produced by at least two young stellar objects (spectral types late B to mid-A) located in a cluster of near-infrared sources near the center of the molecular outflow. The combined mass outflow rate of 1 × 10-4 M☉ yr-1 provides an upper limit on the luminosity of the young stellar objects powering the outflow of 50 L☉ (spectral type later than B7), which is consistent with the near-infrared data. There is no indication of a well-collimated jet, either on large or small scales, that could power the outflow. We conclude that G173.58+2.45 is an excellent example of clustered, intermediate-mass star formation at an age of roughly 105 yr. The near-infrared observations also suggest that the cluster contains at least two mid-to-early B stars, neither of which seem to be in an outflow stage. Our improved understanding of the G173.58+2.45 young star cluster contrasts sharply with previous conclusions, based on low-resolution images, that a single outflow with relatively simple morphology was powered by a jet from an early B star. This analysis illustrates that caution should be exercised before low-resolution images are used to infer conditions in massive star-forming regions and the accretion-outflow mechanism associated with massive stars.