NGC 40

For the Bow Tie Nebula in Centaurus, see Boomerang Nebula.

NGC 40
Observation data (Epoch J2000)
Right ascension	00h 13m 01.015s[1]
Declination	+72° 31′ 19.085″[1]
Distance	~3,500 ly (~1.0 kpc)[2]
Apparent magnitude (V)	11.4,[1] 12.3[2]
Apparent dimensions (V)	38 x 35 arcseconds[2]
Constellation	Cepheus
Physical characteristics
Other designations	Bow-Tie Nebula, Caldwell 2
See also: Planetary nebula, Lists of nebulae

NGC 40 (also known as the Bow-Tie Nebula and Caldwell 2) is a planetary nebula discovered by W.F.Herschel Nov 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^[3] degrees (Celsius). Radiation from the star causes the shed outer layer to heat to about 10,000^[3] degrees (Celsius) and is about one^[3] light-year across. About 30,000^[3] years from now, scientists theorize that NGC 40 will fade away, leaving only a white dwarf star approximately the size of Earth.^[3]

References

1. ^ ^{a b c} "SIMBAD Astronomical Database". Results for NGC 40. http://simbad.u-strasbg.fr/Simbad. Retrieved 2006-12-22. 
2. ^ ^{a b c} O'Meara, Stephen James (2002). Deep Sky Companions: The Caldwell Objects. Sky Publishing Corporation. pp. 22–23. ISBN 0-933346-97-2. 
3. ^ ^{a b c d e} "Chandra X-Ray Observatory". http://chandra.harvard.edu/photo/2005/n40/. Retrieved 2007-06-05. 

External links

• NGC 40 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Astronomical catalogs
NGC:	NGC 38 - NGC 39 - NGC 40 - NGC 41 - NGC 42
Caldwell:	C1 - C2 - C3 - C4

Coordinates: 00^h 13^m 01^s, +72° 31′ 19″