NGC 2403

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Galaxy
NGC 2403
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Image taken with a 60 cm telescope
Image taken with a 60 cm telescope
AladinLite
Constellation giraffe
Position
equinox :  J2000.0 , epoch : J2000.0
Right ascension 07 h 36 m 51.4 s
declination + 65 ° 36 ′ 09 ″
Appearance
Morphological type SAB (s) cd HII / LINER  
Brightness  (visual) 8.2 likes
Brightness  (B-band) 8.9 likes
Angular expansion 23.4 ′ × 11.8 ′
Position angle 127 °
Surface brightness 14.2 mag / arcmin²
Physical data
Affiliation M81 group , LGG 176  
Redshift (445 ± 1)  ·  10 −6  
Radial velocity (133 ± 0) km / s  
Stroke distance
v rad  / H 0 		(10 ± 1)  x  10 6  ly
(3.14 ± 0.23)  Mpc 
history
discovery Wilhelm Herschel
Discovery date November 1, 1788
Catalog names
NGC  2403 • UGC  3918 • PGC  21396 • CGCG  310-003 • MCG  + 11-10-007 • IRAS  07320 + 6543 • 2MASX  J07365139 + 6536091 • GC  1541 • H  V 44 •

NGC 2403 is a bar-spiral galaxy of the Hubble type SBc in the constellation Giraffe in the northern sky . It is around 10 million light years away from the Milky Way and has a diameter of around 70,000 light years .
It has an angular dimension of 23.4 '× 11.8' and an apparent magnitude of 8.2 mag. This galaxy, which can easily be seen in good binoculars, is one of the brightest galaxies in the northern sky that has not been included in the Messier catalog .

In the center of this galaxy are several large open star clusters with massive, very hot stars that are embedded in HII regions . From these areas we receive not only H-alpha , but also radiation in the far ultraviolet and even soft X-rays .

That means: The first of the massive stars formed here have already exploded as supernovae . Their shock waves have heated the hydrogen gas of the respective star formation region so much that it emits soft X-ray emissions. The remaining, unaffected gas is stimulated by the ultraviolet radiation of the currently existing massive stars to glow in the hydrogen lines . These also contribute to the observed distant UV radiation.

The galaxy is a member of the M81 galaxy group and is approximately 12 million light years away. In 2004, the 2004dj supernova erupted in this galaxy . As early as 2002, SN 2002kg and before that SN 1954J were observed in NGC 2403.

NGC 2403 was discovered on November 1, 1788 by the German-British astronomer Wilhelm Herschel .

Web links

Commons : NGC 2403  - Album containing pictures, videos and audio files

Individual evidence

  1. ↑ a b c d e NASA / IPAC EXTRAGALACTIC DATABASE
  2. ↑ a b c d e SEDS : NGC 2403
  3. ↑ Seligman
  4. ↑ Klaus-Peter Schröder: NGC 2403: Much similarity to M 33; in: Stars and Space , February 2013, p. 71 ff.