The vast majority of stars form in clusters of different sizes and stellar population. A significant fraction of these clusters lie in proximity to hottest, massive stars. The energetic radiation from even just a few of these massive stars in a cluster can have dramatic effects on the star formation process, the evolution of circumstellar disks around the stars, and on the entire cluster and its natal molecular cloud. For example, there is strong evidence that the massive stars can trigger the formation of new generations of low-mass stars in the parental clouds.
Massive stars can also disrupt the formation of circumstellar disks around its nearby stars. These disks can be quickly dissipated by the intense UV radiation, inhibiting the formation of planets. During the early evolution of young clusters hosting massive stars, even the low-mass stars may experience intense UV radiation during their orbital motion around the cluster center, and even their disks will be disrupted. All this means that the formation of planets around stars in clusters may be endangered.
In order to properly understand these processes (and also thanks to the growing evidence that our solar system itself formed in the presence of nearby massive stars), astronomers in the last few decades have put a great effort in the study of how star formation proceeds in the presence of massive stars. CfA astronomers Mario Guarcello, Jeremy Drake, Ned Wright, Joe Hora, Tom Aldcroft, Antonella Fruscione, and Vinay Kashyap, along with their colleagues, have used data from the optical through the mid-infrared to find and categorize 1843 young stars with evidence for surrounding disks located in the Cygnus massive star formatting region.
The scientists analyzed these young sources to estimate their ages, finding that about 155 are about one hundred thousand years old, with many others having ages ranging up to a few millions of years. A total of 1843 young stars are found to have disks, despite the intense UV radiation in their environment. Closer examination of the locations of these disk-bearing stars revealed evidence that some of the star formation has been triggered by local activity. Now that the presence of many disk-bearing stars in UV environments has been established, future research will examine the effects that the radiation has on the disks.
"The Protoplanetary Disks in the Nearby Massive Star-Forming Region Cygnus OB2," M. G. Guarcello, J. J. Drake, N. J. Wright, J. E. Drew, R. A. Gutermuth, J. L. Hora, T. Naylor,T. Aldcroft, A. Fruscione, D. Garc?a-Alvarez, V. L. Kashyap, and R. King, ApJ, 773, 135, 2013.