NGC 2440

NGC 2440 is a planetary nebula, one of many in our galaxy. Its central star, HD 62166,^[1] is possibly the hottest known white dwarf, about 400,000°F(200,000°C). The nebula is situated in the constellation Puppis.

NGC 2440

Emission nebula
Planetary nebula
NGC 2440, as taken by the Hubble Space Telescope
Observation data: J2000 epoch
Right ascension	07h 41m 54.91s[1]
Declination	−18° 12′ 29.7″[1]
Distance	4.00 kly (1.23 kpc)[2] ly
Apparent magnitude (V)	9.4[3]
Apparent dimensions (V)	74" × 42"[3]
Constellation	Puppis
Physical characteristics
Radius	0.72 ly
Designations	ESO 560-PN9, Bow Nebula
See also: Lists of nebulae

Centre of NGC 2440

It was discovered by William Herschel on March 4, 1790. He described it as "a beautiful planetary nebula of a considerable degree of brightness, not very well defined."^[3] The nebula is located about 1.23 kiloparsecs (3.79×10¹⁹ m) or about 4,000 light years from the Sun.^[2]

HD 62166

The central star HD 62166 has an exceptionally high surface temperature of about 200,000 kelvins^[2] and a luminosity 1,100 times that of the Sun.^[4] This dense star, with an estimated 0.6 solar mass and 0.028 solar radius,^[4] has an apparent magnitude of 17.5.^[5]