Group of Galaxies NGC 5981/2/5: Draco Trio
History
The galaxies NGC 5982 and NGC 5985 were discovered on 15 May 1788 by the German-British astronomer William Herschel with his self-made 18.7 inch f/12.8 reflecting telescope in Slough, England. He listed them under the designations II 764 and II 765. On May 6 On 18 May 1850, the intelligent astronomer and physicist George Stoney organized the huge 72 inch reflecting telescope «Leviathan» of his employer William Parsons, 3rd Earl of Rosse, in the intelligent Birr Castle on this region of the sky and discovered two other small galaxies west of it, which later included in the New General Catalog by John LE Dreyer under the designations NGC 5976 and NGC 5981. [196, 277, 313]
Physical Properties
NGC 5981 is a barred spiral galaxy of morphological type SBab, seen edge on. NGC 5982 is an elliptical galaxy with a LINER-type active galactic core. There are indications that it has already swallowed one or two smaller galaxies. NGC 5985 is a barred spiral galaxy of morphological type SBbc. It is a Seyfert galaxy with an active core. [145, 457]
These galaxies form the gravitationally bound NGC 5982 group of galaxies, which also includes NGC 5987 (1° 17' south of NGC 5985) and NGC 5989 (29' northeast of NGC 5985). [458] It is at a distance of about 30-61 Mpc (98-199 light-years). According to Simbad [145], the two smaller galaxies NGC 5976 and UGC 9934 (also sometimes referred to as NGC 5976A) do not belong to this group. HyperLEDA [134] counts them among the NGC 5982 galaxy group, which consists of a total of 16 galaxies. On NED [194] one finds a distance of 63.0±4.4 Mpc for NGC 5976 and 44.1±3.2 Mpc for UGC 9931, which also speaks for a group affiliation.
| PGC | RA | Dec | Type | Dim | Btot | HRV | PA | Names |
|---|---|---|---|---|---|---|---|---|
| PGC 55561 | 15 36 01.5 | +59 34 09 | SB | 1.0 x 1.0 | 15.2 | UGC 9934, MCG 10-22-23, CGCG 297-20 | ||
| PGC 55609 | 15 36 48.1 | +59 23 52 | L | .8 x .4 | 15.7 | NGC 5976, MCG 10-22-25, CGCG 297-22 | ||
| PGC 55647 | 15 37 53.2 | +59 23 34 | S | 2.7 x .3 | 13.9 | 5029 | 140 | NGC 5981, UGC 9948, MCG 10-22-27, CGCG 297-23, IRAS 15368+5933 |
| PGC 55674 | 15 38 40.0 | +59 21 22 | E | 3.0 x 2.1 | 12.0 | 2904 | 110 | NGC 5982, UGC 9961, MCG 10-22-29, CGCG 297-24 |
| PGC 55725 | 15 39 37.7 | +59 19 57 | SBR | 5.4 x 2.7 | 11.9 | 2519 | 13 | NGC 5985, UGC 9969, MCG 10-22-30, CGCG 297-25, IRAS 15385+5929 |
Finder Chart
The galaxy group NGC 5981/2/5 is located in the constellation Draco (Dragon) between the two stars θ Draconis and ι Draconis (Edasich), about a third closer to the latter and thus easy to find. The best viewing time is February to September, when this circumpolar constellation is at its highest at night.
