NGC 40

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Planetary nebula
data from NGC 40
Photo from the Hubble Space Telescope
Photo from the Hubble Space Telescope
AladinLite
Constellation Cepheus
Position
equinox : J2000.0
Right ascension 00h 13m 01.0s
declination + 72 ° 31 ′ 19 ″
Appearance
Apparent brightness  (visual) 12.3 mag 
Apparent brightness  (B-band) 10.7 mag 
Angular expansion 1.23 ′ × 1.23 ′  
Central star
designation HD  826 
Apparent brightness 11.6 mag 
Spectral class WC 
Physical data
Redshift −0.000068 
Radial velocity −20.4 km / s 
distance 3500 ly 
diameter 0.6 ly
Age 4500 years
history
discovery Wilhelm Herschel
Date of discovery November 25, 1788
Catalog names
 NGC  40 •  PK  120 + 9.1 •  GC  20 •  H  IV 58 •  h  8 • PN G120.0 + 09.8

NGC 40 is a planetary nebula in the constellation Cepheus . The star that has repelled its outer shell has a temperature of 50,000 degrees Celsius and is roughly the size of Earth . This central star has an enormously high density, which is typical for white dwarfs, and thus around 70% solar mass despite its small diameter. The gases surrounding it have a temperature of 10,000 degrees Celsius. NGC 40 is estimated to be around 4,500 years old, with its gas clouds still expanding at about 29 km / s.

Visual observation

Recording with a ToUcam on a 14 "SCT

NGC 40 can already be seen well in a medium amateur telescope with approx. 8 ". While the bright central star in the eyepiece of a 14-inch device is immediately noticeable, you will be somewhat disappointed about the sheen of the gas cloud around it, because it glows inside you Spectral range to which our eyes are less sensitive: a delicate, colorless and slightly structured "smoke ring" can be seen quite clearly, but not brightly (compared to M57 ).

discovery

The planetary nebula NGC 40 was discovered on November 25, 1788 by the German-British astronomer Friedrich Wilhelm Herschel .

Web links

Commons : NGC 40  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b NASA / IPAC EXTRAGALACTIC DATABASE
  2. ↑ a b SEDS: NGC 40
  3. ↑ a b SIMBAD database, operated at CDS
  4. ↑ Seligman