An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Any group or set of six. → Seyfert's sextet.

From Latinized sestet, from It. sestetto, diminutive of sesto "sixth," from L. sextus "sixth," from sex, → six.

Šeštâyé, from šeš, → six, + tâ "fold, plait, ply; piece, part" (Mid.Pers. tâg "piece, part") + -(y)é nuance suffix.

A group of galaxies about 190 million → light-years away in the head portion of the constellation → Serpens. The group appears to contain six members, but actually contains only four → interacting galaxies. A face-on → spiral galaxy lies in the distant background and appears only by chance aligned with the main group. Also, a prominent condensation is likely not a separate galaxy, but a → tidal tail of stars flung out by the galaxies' gravitational interactions. The interacting galaxies are tightly packed into a region around 100,000 light-years across, comparable to the size of our own Milky Way galaxy, making this one of the densest known galaxy groups.

Discovered by the American astronomer Carl Keenan Seyfert (1911-1960) using photographic plates made at the Barnard Observatory of Vanderbilt University. → sextet.