|   | 
Credit & Copyright: Bob Franke    
(Focal Pointe Observatory)    
    
    
Explanation:
Braided, serpentine filaments of glowing gas    
suggest this nebula's popular name, The Medusa Nebula.    
    
Also known as Abell 21, this Medusa is an old    
planetary nebula    
some 1,500 light-years away in the constellation    
Gemini.    
    
Like its mythological    
namesake, the nebula is associated    
with a dramatic transformation.    
    
The planetary    
nebula phase represents a final stage in    
the    
evolution of low mass stars    
like the    
sun,    
as they transform themselves from red giants to hot white dwarf    
stars and in the process shrug off their outer layers.    
    
Ultraviolet    
radiation    
from the hot star powers the nebular glow.    
    
The Medusa's transforming star is    
near the center    
of the overall bright    
crescent    
shape.    
    
In this deep,    
wide telescopic view,    
fainter filaments clearly extend below and to    
the left of the bright crescent region.    
    
The Medusa    
Nebula is estimated to be over 4 light-years across.    
    
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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: planetary nebula
Publications with words: planetary nebula
See also:
- APOD: 2025 August 31 Á NGC 7027: The Pillow Planetary Nebula
- APOD: 2025 August 22 Á A Tale of Two Nebulae
- APOD: 2025 August 5 Á NGC 6072: A Complex Planetary Nebula from Webb
- APOD: 2025 July 29 Á A Helix Nebula Deep Field
- APOD: 2025 July 13 Á Planetary Nebula Mz3: The Ant Nebula
- APOD: 2025 June 9 Á Between Scylla and Charybdis: A Double Cosmic Discovery
- APOD: 2025 May 14 Á NGC 1360: The Robins Egg Nebula
