NGC 2261

NGC 2261
Reflection nebula

An image of NGC 2261 by the Hubble space telescope.
Credit: HST/NASA/JPL.
Observation data: J2000.0 epoch
Subtype variable nebula
Right ascension 6h 39m 10s[1]
Declination +8° 45[1]
Distance 2,500 ly
Apparent magnitude (V) 9.0
Apparent dimensions (V) 2
Constellation Monoceros
Designations Hubble's Variable Nebula,[1] Caldwell 46

NGC 2261 (also known as Hubble's Variable Nebula or Caldwell 46) is a variable nebula located in the constellation Monoceros. It is illuminated by the star R Monocerotis (R Mon), which is not directly visible itself.

NGC 2261 was imaged as Palomar Observatory's Hale Telescope's first light by Edwin Hubble on January 26, 1949,[2] some 20 years after the Palomar Observatory project began in 1928. Hubble had studied the nebula previously at Yerkes and Mt. Wilson.[2]

One explanation proposed for the variability is that dense clouds of dust near R Mon periodically block the illumination from the star.[3]

See also

References

External links

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