Bow-Tie Nebula

As seen from Misti Mountain Observatory.

Observation Data
Epoch: J2000
Right Ascension: 00h 13m 01.015s[1]
Declination: +72° 31′ 19.085″[1]
Constellation: Cepheus
Apparent Dimensions (V): 38 x 35 arcseconds[2]
Apparent Magnitude (V): 10.7,[1] 11.6[2]
Absolute Magnitude (V):
Type: 3b+b
Helio Radial Velocity: -20.50
Redshift: -0.000068
Distance: ~3,500 ly (~1.0 kpc)[2]
Other Designations
Bow-Tie Nebula, Caldwell 2

NGC 40 (also known as the Bow-Tie Nebula and Caldwell 2) is a planetary nebula discovered by William Herschel on November 25, 1788, and is composed of hot gas around a dying star. The star has ejected its outer layer which has left behind a smaller, hot star with a temperature on the surface of about 50,000 degrees Celsius.[3] Radiation from the star causes the shed outer layer to heat to about 10,000 degrees Celsius,[3] and is about one light-year across.[3] About 30,000 years from now, scientists theorize that NGC 40 will fade away, leaving only a white dwarf star approximately the size of Earth.[3]


  1. 1.0 1.1 1.2 SIMBAD Astronomical Database. Results for NGC 40. Retrieved on 2006-12-22.
  2. 2.0 2.1 2.2 O'Meara, Stephen James (2002). Deep Sky Companions: The Caldwell Objects. Sky Publishing Corporation, 22–23.
  3. 3.0 3.1 3.2 3.3 Chandra X-Ray Observatory. Retrieved on 2007-06-05.