Caption: An image of Seyfert's Sextet.


  1. Seyfert's Sextet in constellation Serpens was discovered by Carl Seyfert (1911--1960) in 1951.

  2. The image appears to be approximately true color, but it's hard to know with astrophotography since the image makers can make the colors anything they like and often enhance colors to bring out features.

  3. Seyfert's Sextet consists of 6 galaxies. Five are gravitationally bound together into a small compact galaxy group (or VERY POOR galaxy cluster which is ∼ 58 Mpc away.

  4. The 6th galaxy is a background galaxy at ∼ 269 Mpc and is NOT gravitationally bound bound to the others. It's the face-on spiral (NGC 6027d) whose apparent size is small.

    Since NGC 6027d is ∼ 5 times farther away than the other 5 galaxies, it is NOT surprising that it has apparent size ∼ 1/3 of those others. That the apparent size is NOT ∼ 1/5 of the others must be because it is intrinsically a larger galaxy.

  5. The names and types of the galaxies in Hubble sequence galaxy types/de Vaucouleurs system are:

    1. NGC 6027e: At the upper left: S0? seen sort of edge-on (see also NED: NGC 6027e; Sinbad: NGC 6027e).

    2. NGC 6027: At the upper mid: an S0 pec seen sort of edge-on (see also NED: NGC 6027; Sinbad: NGC 6027).

    3. NGC 6027b: At the upper right: an S0 pec seen sort of edge-on (see also NED: NGC 6027b; Sinbad: NGC 6027b).

    4. NGC 6027a: The middle one from the top of the 3 lower galaxies: an SA pec seen edge-on (see also NED: NGC 6027a; Sinbad: NGC 6027a).

    5. NGC 6027c: The bottom one from the top of the 3 lower galaxies: an SB(s)c? seen edge-on (see also NED: NGC 6027c; Sinbad: NGC 6027c).

    6. NGC 6027d: The top one from the top of the 3 lower galaxies: an S? or Scd D? (see also NED: NGC 6027d; Sinbad: NGC 6027d).

      The "D" in Scd D may mean D galaxy (i.e., diffuse galaxy), but no one's telling.

      Recall NGC 6027d is the background galaxy at distance ∼ 269 Mpc.

    Note "pec" stands for peculiar galaxy---but all galaxies are peculiar in one way or another---they are individuals, NOT identicals.

    Peculiar galaxies are just a bit more peculiar than most.

  6. The 5 gravitationally bound galaxies are interacting galaxies. The top 3 of them are strongly interacting as can be seen by the connecting bridges (Cimatti-163) of stars joining them.

  7. For interacting galaxies explicated, see insert interacting_galaxies.html below (local link / general link: interacting_galaxies.html):


  8. As aforementioned, the galaxy interaction for Seyfert's Sextet is clear for the 3 top galaxies that have faint bridges of stars connecting them and whose galactic disks maybe look a bit distorted.

    There are NO obvious tidal tails in this image.

  9. The interacting galaxies of Seyfert's Sextet should continue interacting for hundreds of millions of years and eventually undergo a galaxy merger to become a giant elliptical galaxy (see Wikipedia: Seyfert's Sextet).

Credit/Permission: NASA/ESA, circa or before 2008 (uploaded to Wikipedia by User:Kosame~commonswiki, 2008) / Public domain.
Image link: Wikipedia: File:Seyfert Sextet full.jpg.
Local file: local link: seyfert_sextet.html.
File: Galaxies file: seyfert_sextet.shtml.