|   | 
Credit & Copyright: H. Olofsson  
(Stockholm Observatory) et al.  
  
  
Explanation:
TT Cygni is a  
cool red  
giant star with a wind.  
  
This false-color picture of TT Cyg was made using a coordinated array of  
millimeter wavelength radio telescopes and shows radio emission  
from carbon monoxide (CO) molecules in the surrounding gas.  
  
The central emission is from material blown off the  
red giant  
over a few hundred years while the thin ring,  
with a radius of about 1/4 light-year, actually represents  
a shell of gas expanding outward for 6,000 years.  
  
Carbon stars like TT Cyg are so named  
for their apparent abundance of carbon containing molecules.  
  
The carbon is likely the dredged-up ashes of  
nuclear helium burning in the stellar interior.  
  
Carbon stars loose a significant fraction of  
their total mass in the form of a  
stellar wind  
which ultimately enriches the  
interstellar gas - the source of  
material for future  
generations of stars.  
  
TT Cyg is about 1,500 light-years away in the  
constellation Cygnus.  
  
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Based on Astronomy Picture
Of the Day
Publications with keywords: stellar wind - red giant - carbon star
Publications with words: stellar wind - red giant - carbon star
See also:
