NGC 2440

NGC 2440
Observation data (Epoch J2000)
Right ascension	07h 41m 54.91s[1]
Declination	-18° 12′ 29.7″[1]
Distance	4.00 kly (1.23 kpc)[2]
Apparent magnitude (V)	9.4[3]
Apparent dimensions (V)	74" × 42"[3]
Constellation	Puppis
Physical characteristics
See also: Planetary nebula, Lists of nebulae

NGC 2440 is a planetary nebula, one of many in our galaxy. Its central star, HD62166^[1], is possibly the hottest known white dwarf. The nebula is situated in the Puppis constellation.

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]

HD62166

HD62166 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 18.9.^[1].

External links

• Hubble Space Telescope reveals NGC 2440 on YouTube
• Astronomy Picture of the Day (15 February 2007): Planetary Nebula NGC 2440
• Astronomy Picture of the Day (7 May 2006): NGC 2440: Cocoon of a New White Dwarf
• Astronomy Picture of the Day (30 November 1995): NGC 2440 Nucleus: The Hottest Star?

Notes

1. ^ ^{a b c d} (SIMBAD 2007)
2. ^ ^{a b c} (Nemiroff & Bonnell 2007)
3. ^ ^{a b c} (O'Meara 2007)
4. ^ ^{a b} (James & Marion 2006)

References

• SIMBAD (January 9, 2007), Results for NGC 2440, SIMBAD, Centre de Données Astronomiques de Strasbourg, http://simbad.u-strasbg.fr/simbad/sim-id?protocol=html&Ident=NGC+2440 
• Nemiroff, Robert; Bonnell, Jerry (February 15, 2007), Astronomy Picture of the Day, ASD at NASA / GSFC & Michigan Tech. U., http://antwrp.gsfc.nasa.gov/apod/ap070215.html 
• James, Renée; Marion, Howie (April 2006), "X-treme Stars of the cosmos", Astronomy (Kalmbach Publishing Co.) 34 (4): 34–39 
• O'Meara, Stephen James (2007), "Albino Butterfly, Kiss Nebula, Little Lips Nebula: NGC 2440", Hidden Treasures (Cambridge University Press): 204–208