NGC 646

NGC 646
Observation data (J2000 epoch)
ConstellationHydrus
Right ascension01h 37m 25.5s[1]
Declination−64° 53′ 47″[1]
Distance392 Mly
Apparent magnitude (B)15.65
Surface brightness22.53 mag/arcsec2
Characteristics
TypeSAB(s)c pec?[1]
Other designations
PGC 6010[1]

NGC 646 is a large barred spiral galaxy located in the constellation Hydrus.[2] Its speed relative to the cosmic microwave background is 8,145 ± 19 km/s, which corresponds to a Hubble distance of 120.1 ± 8.4 Mpc (~392 million ly). NGC 646 was discovered by British astronomer John Herschel in 1834.[3] It forms an interacting galaxy pair.[4]

Luminosity

The luminosity class of NGC 646 is III.[1] It has surface brightness equal to 14.69 mag/am2.[5] NGC 646 is a low surface brightness galaxy (LSB).[5] LSB galaxies are diffuse (D) galaxies with a surface brightness less than one magnitude lower than that of the ambient night sky.

Distance

The Hubble distance of PGC 6014, the galaxy to the east of NGC 646, is 106.4 ± 7.5 Mpc (~347 million ly).[6] A distance of approximately 45 million light years therefore separates these two galaxies which appear to be neighbors in the image. Their gravitational interaction, if there is any interaction, should therefore be of short duration.[7]

See also

References

  1. ^ a b c d e "Your NED Search Results". ned.ipac.caltech.edu. Retrieved 2024-04-18.
  2. ^ "NGC 646 NED02 - Elliptical/Spiral Galaxy in Hydrus | TheSkyLive.com". theskylive.com. Retrieved 2024-04-15.
  3. ^ "New General Catalog Objects: NGC 600 - 649". cseligman.com. Retrieved 2024-04-18.
  4. ^ Danziger, I. J.; Schuster, H. -E. (1974-08-01). "The interacting galaxy system NGC 646". Astronomy and Astrophysics. 34: 301–303. Bibcode:1974A&A....34..301D. ISSN 0004-6361.
  5. ^ a b astrovalleyfield.ca http://astrovalleyfield.ca/AstronomieCompl/NGC%20et%20autres/WolfgangS/N0600_exc_web.htm. Retrieved 2024-05-03. {{cite web}}: Missing or empty |title= (help)
  6. ^ "Your NED Search Results". ned.ipac.caltech.edu. Retrieved 2024-04-18.
  7. ^ "New General Catalog Objects: NGC 600 - 649". cseligman.com. Retrieved 2024-04-18.