File:M91_wfc3_4_crop_v2_final.jpg · Wikimedia Commons · See Wikimedia Commons
Messier 91 is a spiral galaxy located millions of light-years away that was catalogued by astronomer Charles Messier in the 18th century. It serves as one of many deep-sky objects that helps astronomers study the structure and distribution of galaxies across the universe.
AI-generated from the Wikipedia summary — may contain errors.
Key facts
- Constellation
- Coma Berenices
- Right ascension
- 12 35 26.4
- Declination
- +14 ° 29 ′ 47 ″
- Redshift
- 486 ± 4 km/ s
- Distance
- 63 ± 16 Mly (19 ± 5 Mpc )
- Type
- SBb(rs)
- Size
- 32.36 kpc (105,500 ly ) (estimated)
- Apparent size v
- 5.4 ′ × 4.3 ′
via Wikipedia infobox
Wikidata facts
- Distance from Earth
- 16.7
- Image
- M91s.jpg
Show 9 more facts
- Commons category
- Messier 91
- catalog code
- LEDA 41934
- time of discovery or invention
- 1781-03-18
- apparent magnitude
- 10.514
- galaxy morphological type
- SBb
- redshift
- 0.001621
- radial velocity
- 492
- right ascension
- 188.8601250
- declination
- 14.4963194
via Wikidata · CC0
~3 min read
Article
Messier 91 (also known as NGC 4548 or M91) is a barred spiral galaxy that is found in the south of Coma Berenices. It is in the local supercluster and is part of the Virgo Cluster of galaxies. It is about 63 million light-years away from our galaxy. It was the last of a group of eight "nebulae" – the term 'galaxy' only coming into use for these objects once it was realized in the 20th century that they were extragalactic – discovered by Charles Messier in 1781. It is the faintest object in the Messier catalog, with an apparent magnitude of 10.2.
As a result of a bookkeeping error by Messier, M91 was for a long time one of the few missing entries in the Messier catalog, not matching any known object in the sky. It was not until 1969 that amateur astronomer William C. Williams realized that M91 was NGC 4548, which was catalogued by William Herschel in 1784. Some sources contend the nearby spiral galaxy NGC 4571 was considered as a candidate for this object by Herschel.