|   | 
Credit & Copyright: Eric Coles and  
Mel Helm  
  
  
Explanation:
This  
skyscape features dusty  
Sharpless  
catalog emission region  
Sh2-155,  
the Cave Nebula.  
  
In the telescopic image, data taken through a  
narrowband filter tracks the reddish glow of ionized hydrogen atoms.  
  
About 2,400 light-years away, the scene lies  
along the plane of our Milky Way Galaxy  
toward the royal northern constellation  
of Cepheus.  
  
Astronomical explorations of the region reveal that it has  
formed at the boundary of the massive Cepheus B molecular cloud  
and the hot, young stars of the Cepheus OB 3  
association.  
  
The bright rim of  
ionized  
hydrogen gas is energized by radiation from the hot stars,  
dominated by the brightest star above and left of picture center.  
  
Radiation driven  
ionization fronts are likely triggering collapsing cores  
and new star formation within.  
  
Appropriately sized for a stellar nursery, the cosmic cave is  
over 10 light-years across.  
  
  
  
  
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Based on Astronomy Picture
Of the Day
Publications with keywords: molecular cloud
Publications with words: molecular cloud
See also:
