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Credit & Copyright: Nicolas Lefaudeux  
 
Explanation:
What created the unusual red tail in Comet NEOWISE?  
  
Sodium.   
  
A spectacular sight back in the summer of 2020, Comet NEOWISE,   
at times, displayed something more than just a   
surprisingly  
striated   
white dust tail and a   
pleasingly patchy blue   
ion tail.  
  
Some color sensitive   
images showed an unusual red tail, and   
analysis showed much of this third tail's color was emitted by sodium.  
   
Gas rich in sodium atoms might have been liberated from   
Comet NEOWISE's warming nucleus in early July by bright  
sunlight, electrically charged by   
ultraviolet sunlight, and then pushed out by the   
solar wind.  
  
The   
featured image   
was captured in mid-July from   
Brittany,   
France   
and shows the real colors.  
  
Sodium comet tails have been seen before but are   
rare --   
this one disappeared by late July.   
  
Comet C/2020 F3 (NEOWISE)   
has since faded,   
lost all of its bright tails, and now approaches the orbit of   
Jupiter   
as it heads back to the outer   
Solar System, to return only in about 7,000 years.   
  
  
    
 Astrophysicists:   
Browse 2,400+ codes in the Astrophysics Source Code Library 
   
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NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: comet
Publications with words: comet
See also:
- APOD: 2025 September 30 Á Comet Lemmon Brightens
 - APOD: 2025 September 29 Á Two Camera Comets in One Sky
 - APOD: 2025 September 26 Á A SWAN an ATLAS and Mars
 - APOD: 2025 September 18 Á Comet C/2025 R2 SWAN
 - APOD: 2025 September 16 Á New Comet SWAN25B over Mexico
 - APOD: 2025 July 7 Á Interstellar Comet 3I ATLAS
 - Comet C/2025 F2 SWAN
 

