Skip directly to content

Star birth in Cepheus

NSF Award:

Management and Operations of the National Optical Astronomy Observatory  (Association of Universities for Research in Astronomy, Inc.)

Congressional Districts:
Research Areas:

Watching star birth isn't easy: Tens of millions of years are needed to form a star like the sun. Much like archaeologists, who reconstruct ancient cities from shards of debris strewn over time, astronomers reconstruct the birth process of stars indirectly by observing stars in different stages of the process and inferring the changes that take place. Studies show that half of the common stars, including the sun, formed in massive clusters, rich with young stars, from which they eventually escaped.

Thomas Allen of the University of Toledo and an international team of astronomers have been observing the Cep OB3b region, where stars are forming in the northern constellation of Cepheus. The cluster is similar in some ways to the famous cluster found in the Orion Nebula. But unlike the Orion Nebula, relatively little dust and gas obscures the view of Cep OB3b. The cluster's massive, hot stars have blown out cavities in the gaseous cloud with their intense ultraviolet radiation, which mercilessly destroys everything in its path.

Observations of the Cepheus cluster will provide a deeper understanding of the history of the origins of an important stellar constituent and Cep OB3b may reveal what the Orion Nebular cluster will look like in the future.

Allen and his colleagues have found that the total number of young stars in the cluster is as high as 3000. Infrared observations of the stars from the NASA Spitzer satellite show about 1000 stars surrounded by disks of gas and dust from which solar systems may form. As the stars age, the disks disappear as the dust and gas get converted into planets or are dispersed into space.

These observations point to a new mystery: Although the stars in Cep OB3b are thought to be about 3 million years old, in some parts of the cluster most of the stars have lost their disks, suggesting that the stars in those parts are older. This indicates that the cluster is surrounded by older stars, potential relics of previous clusters that have since expanded and dispersed.

To search for evidence for these relic clusters, the team is using the Mosaic camera on the 0.9-meter telescope run by the WIYN 0.9-meter Consortium on Kitt Peak near Tucson, Ariz. WIYN Consortium partners are Austin Peay State University, Haverford College, Indiana University, Rochester Institute of Technology, San Francisco State University, University of St. Thomas, University of Wisconsin-Madison, University of Wisconsin-Stevens Point, University of Wisconsin-Whitewater and the Wisconsin Space Grant Consortium.


  • a composite image shows massive young stars in a cluster; surrounding smaller stars may be forming planetary systems
This composite image shows massive young stars that are heating gas and dust; surrounding smaller stars may be forming planetary systems.
T.A. Rector (University of Alaska Anchorage), T. Allen (University of Toledo) and WIYN/NOAO/AURA/NSF

Recent Award Highlights

an adaptive optics system captured these supersonic gas bullets in space

Adaptive optics detail the turmoil of a stellar nursery

Technique offers unprecedented clarity and sky coverage

Research Areas: Astronomy & Space Locations: Washington DC International
a narrow dust ring surrounds the star fomalhaut

Sensitive ALMA identifies dust ring for newly formed star

Radio array observes debris around nearby star Fomalhaut

Research Areas: Astronomy & Space Locations: Washington DC International