A Spitzer View of Star Formation in the Cygnus X North Complex

TL;DR

This study uses Spitzer and other data to analyze star formation in Cygnus X North, revealing clustering of young stars around massive B stars and suggesting triggered star formation in filamentary structures.

Contribution

First comprehensive infrared and spectroscopic analysis of Cygnus X North, identifying young stellar objects and their spatial distribution relative to massive stars.

Findings

YSOs are clustered near massive B stars.

50-70% of infrared excess sources are in clusters with >10 members.

Class II objects are in dense clusters, while Class I are in filamentary structures.

Abstract

We present new images and photometry of the massive star forming complex Cygnus X obtained with IRAC and MIPS on the Spitzer Space Telescope. A combination of IRAC, MIPS, UKIDSS, and 2MASS data are used to identify and classify young stellar objects. Of the 8,231 sources detected exhibiting infrared excess in Cygnus X North, 670 are classified as Class I and 7,249 are classified as Class II. Using spectra from the FAST spectrograph at the Fred L. Whipple Observatory and Hectospec on the MMT, we spectrally typed 536 sources in the Cygnus X complex to identify the massive stars. We find that YSOs tend to be grouped in the neighborhoods of massive B stars (spectral types B0 to B9). We present a minimal spanning tree analysis of clusters in two regions in Cygnus X North. The fraction of infrared excess sources that belong to clusters with >10 members is found to be 50--70%. Most Class II objects lie in dense clusters within blown out HII regions, while Class I sources tend to reside in more filamentary structures along the bright-rimmed clouds, indicating possible triggered star formation.