NGC 6956
| Galaxie NGC 6956 | |
|---|---|
 | |
| AladinLite | |
| Sternbild | Delphin |
| Position Äquinoktium: J2000.0, Epoche: J2000.0 | |
| Rektaszension | 20h 43m 53,7s [1] |
| Deklination | +12° 30′ 43″ [1] |
| Erscheinungsbild | |
| Morphologischer Typ | SBb[1] |
| Helligkeit (visuell) | 12,4 mag[2] |
| Helligkeit (B-Band) | 13,2 mag[2] |
| Winkelausdehnung | 1,9′ × 1,9′[2] |
| Flächenhelligkeit | 13,6 mag/arcmin²[2] |
| Physikalische Daten | |
| Zugehörigkeit | LGG 440[1][3] |
| Rotverschiebung | 0,015511 ± 0,000030[1] |
| Radialgeschwindigkeit | (4650 ± 9) km/s[1] |
| Hubbledistanz H0 = 73 km/(s • Mpc) | (216 ± 15) · 106 Lj (66,3 ± 4,6) Mpc [1] |
| Geschichte | |
| Entdeckung | Wilhelm Herschel |
| Entdeckungsdatum | 19. Oktober 1784 |
| Katalogbezeichnungen | |
| NGC 6956 • UGC 11619 • PGC 65379 • CGCG 425-001 • MCG +02-53-001 • 2MASX J20435368+1230429 • GC 4598 • H III 219 • h 2086 • LDCE 1416 NED001 | |
NGC 6956 ist eine Balken-Spiralgalaxie vom Hubble-Typ SBb im Sternbild Delphin. Sie ist schätzungsweise 216 Millionen Lichtjahre von der Milchstraße entfernt.
Das Objekt wurde am 19. Oktober 1784 von Wilhelm Herschel entdeckt.[4]
NGC 6956-Gruppe (LGG 440)
| Galaxie | Alternativname | Entfernung/Mio. Lj |
|---|---|---|
| PGC 65281 | UGC 11620 | |
| PGC 65293 | UGC 11623 | |
| NGC 6956 | PGC 65269 | 216 |
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NASA: Against an inky black backdrop, the blue swirls of spiral galaxy NGC 6956 stand out radiantly. NGC 6956 is a barred spiral galaxy, a common type of spiral galaxy with a bar-shaped structure of stars in its center. This galaxy exists 214 million light-years away in the constellation Delphinus.
Scientists used NASA’s Hubble Space Telescope to image NGC 6956 to study its Cepheid variable stars, which are stars that brighten and dim at regular periods. Since the period of Cepheid variable stars is a function of their brightness, scientists can measure how bright these stars appear from Earth and compare it to their actual brightness to calculate their distance. As a result, these stars are extremely useful in determining the distance of cosmic objects, which is one of the hardest pieces of information to measure for extragalactic objects.
This galaxy also contains a Type Ia supernova, which is the explosion of a white dwarf star that was gradually accreting matter from a companion star. Like Cepheid variable stars, the brightness of these types of supernovae and how fast they dim over time enables scientists to calculate their distance. Scientists can use the measurements gleaned from Cepheid variable stars and Type Ia supernovae to refine our understanding of the rate of expansion of the universe, also known as the Hubble Constant.