NGC 7771 Galaxy Group
History
The three galaxies were discovered on 18 September 1784 by the German-British astronomer William Herschel with his 18.7 inch reflecting telescope. He cataloged them as II 230 (NGC 7769) and II 231 (NGC 7770 and NGC 7771). Herschels class II stood for faint nebulae. [277, 463]
Physical Properties
The galaxies are in gravitational interaction with each other. NGC 7771 is undergoing a massive star formation spurt, which may have been caused by the dwarf galaxy NGC 7770. This appears to be in the early stages of a merger with NGC 7771. The resulting tidal disturbances may have caused the apparent two-armed spiral pattern and forced a significant portion of the disk gas inward. [438] Distances range from 58 Mpc to 63 Mpc (189 to 205 million light years) [145]
| Name | RA | Dec | Type | bMag | vMag | B-V | SB | Dim | PA | z | D(z) | MD | Dreyer Description | Identification, Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NGC 7769 | 23 51 04.1 | +20 09 02 | Gx (Sb) | 12.8 | 12.0 | 0.8 | 14.2 | 3.2 × 2.7 | 170 | 0.014046 | 59.33 | pF, pS, R, mbM | WH II 230; h 2274; GC 5020; UGC 12808; MCG 3-60-30; CGCG 455-54; IRAS 23485+1952; KCPG 592A; KAZ 346; KUG 2348+198A | |
| NGC 7770 | 23 51 22.5 | +20 05 49 | Gx (S0-a) | 14.4 | 13.8 | 0.6 | 13.1 | 0.7 × 0.4 | 17 | 0.013733 | 58.01 | vF, vS, iR, s of 2 | GC 5021; UGC 12813; MCG 3-60-34; CGCG 455-57; KUG 2348+198B; KAZ 347; NPM1G +19.0594 | |
| NGC 7771 | 23 51 24.6 | +20 06 44 | Gx (SBa) | 13.1 | 12.3 | 0.8 | 13.1 | 2.4 × 1.1 | 68 | 0.014267 | 60.26 | 45.450 | pB, pL, E 84°, bM, n of 2 | WH II 231; h 2275; GC 5022; UGC 12815; MCG 3-60-35; CGCG 455-58; IRAS 23488+1949; KCPG 592B; KAZ 348; KUG 2348+198C |
Finder Chart
The NGC 7771 galaxy group is located in the constellation Pegasus. On 19 September it is in opposition to the Sun and crosses the meridian at local midnight. The best observation time is June to December, when it is highest at night.
