|Right ascension||00h 13m 01.015s|
|Declination||+72° 31′ 19.085″|
|Distance||~3,500 ly (~1.0 kpc)|
|Apparent magnitude (V)||10.7, 11.6|
|Apparent dimensions (V)||38 x 35 arcseconds|
|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. Radiation from the star causes the shed outer layer to heat to about 10,000 degrees Celsius, and is about one light-year across. 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.
- NGC 40 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images