title: NGC 4567 and NGC 4568
text: NGC 4567 and NGC 4568 (nicknamed the Butterfly Galaxies or Siamese Twins) are a set of unbarred spiral galaxies about 60 million light-years away in the constellation Virgo. They were both discovered by William Herschel in 1784. They are part of the Virgo Cluster of galaxies. 
  
  These galaxies are in the process of colliding and merging with each other, as studies of their distributions of neutral and molecular hydrogen show, with the highest star-formation activity in the part where they overlap. However, the system is still in an early phase of interaction.
  
  Four supernovae have been observed in the Butterfly Galaxies:  SN 1990B (type Ib, mag. 16), SN 2004cc (type Ic, mag. 17.5), SN 2020fqv (type IIb, mag. 19), and SN 2023ijd (type II, mag. 16.8).
  
  Naming controversy
  The two galaxies were nicknamed "Siamese Twins" because they appear to be connected. On August 5, 2020, NASA announced that they would not use that nickname in an effort to avoid systemic discrimination in their terminology.
  
  See also 
  
   Antennae Galaxies
   Eyes Galaxies
  
  Notes
  
  References
  
  External links 
   Kopernik Space Images, Spiral Galaxies NGC 4568 and NGC 4567 aka "The Siamese Twins" : Supernova 2004cc, George Normandin (29 June 2004)
   Skyhound, The Siamese Twins
   SIMBAD, VCC 1673 : NGC 4567 -- Galaxy in Pair of Galaxies
   SIMBAD, VCC 1676 : NGC 4568 -- Galaxy in Pair of Galaxies
   NED, VV 219
   NED, NGC 4567
   NED, NGC 4568
  
  Virgo (constellation)
  Virgo Cluster
  4567
  42064
  Interacting galaxies
  Unbarred spiral galaxies
  Overlapping galaxies