NGC 691 | |
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Observation data (J2000 epoch) | |
Constellation | Aries |
Right ascension | 01h 50m 41.7s [1] |
Declination | +21° 45′ 36″ [1] |
Redshift | 0.008889 ± 0.000013 [1] |
Helio radial velocity | 2,665 ± 5 km/s [1] |
Distance | 119 ± 14 Mly (36.5 ± 4.3 Mpc) [1] |
Apparent magnitude (V) | 11.5 [2] |
Characteristics | |
Type | SA(rs)bc [1] |
Apparent size (V) | 3.5′ × 2.6′ [1] |
Other designations | |
UGC 1305, CGCG 482-023, MCG +04-05-019, PGC 6793 [1] |
NGC 691 is an unbarred spiral galaxy located in the constellation Aries. It is located at a distance of circa 120 million light years from Earth, which, given its apparent dimensions, means that NGC 691 is about 130,000 light years across. It was discovered by William Herschel on November 13, 1786. [3]
NGC 691 features a multiple ring structure, with three rings recognised in the infrared, with diameters of 1.03, 1.67, and 2.79 arcminutes. [4] When imaged in H-alpha, the galaxy appears patchy. The total star formation rate of the galaxy is estimated to be about 0.6 M☉ per year. [5] One supernova has been observed in NGC 691, SN 2005W. It was discovered by Yoji Hirose in unfiltered CCD frames taken on Feb. 1.442 UT with a 0.35-m f/6.8 Schmidt-Cassegrain reflector. The supernova was located 56" east and 1" south of the center of NGC 691 and at the time of the discovery had an apparent magnitude of 15.2. [6] Spectrographic observations indicated it was a type Ia supernova about a week before maximum. [7] The peak magnitude of the supernova was 14.3, on February 10.759. [8]
NGC 691 is the foremost member of a galaxy group known as the NGC 691 group. Other members of the group include IC 163, NGC 678, NGC 680, NGC 694, IC 167, and NGC 697. [9]
NGC 4309 is a lenticular galaxy located about 55 million light-years away in the constellation Virgo. The galaxy was discovered by astronomer Christian Peters in 1881 and is a member of the Virgo Cluster.
NGC 4323 is a lenticular or dwarf elliptical galaxy located about 52.5 million light-years away in the constellation Coma Berenices. The galaxy was discovered in 1882 by astronomer Wilhelm Tempel and is a member of the Virgo Cluster.
NGC 5238 is an irregular galaxy in the constellation Canes Venatici. Located at a comoving distance of 4.51 Mpc, it is 64.4 arcseconds in diameter. It has sometimes been classified as a blue compact dwarf galaxy. Although some authors have hypothesized it to be a member of the M101 Group of galaxies, it is currently believed to be an isolated galaxy.
NGC 4274 is a barred spiral galaxy located in the constellation Coma Berenices. It is located at a distance of circa 45 million light years from Earth, which, given its apparent dimensions, means that NGC 4274 is about 95,000 light years across. It was discovered by William Herschel in 1785.
NGC 4494 is an elliptical galaxy located in the constellation Coma Berenices. It is located at a distance of circa 45 million light years from Earth, which, given its apparent dimensions, means that NGC 4494 is about 60,000 light years across. It was discovered by William Herschel in 1785.
NGC 4699 is an intermediate spiral galaxy located in the constellation Virgo. It is located at a distance of circa 65 million light years from Earth, which, given its apparent dimensions, means that NGC 4699 is about 85,000 light years across. It was discovered by William Herschel in 1786. It is a member of the NGC 4699 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.
NGC 3675 is a spiral galaxy located in the constellation Ursa Major. It is located at a distance of circa 50 million light years from Earth, which, given its apparent dimensions, means that NGC 3675 is about 100,000 light years across. It was discovered by William Herschel in 1788.
NGC 6753 is a massive unbarred spiral galaxy, seen almost exactly face-on, in the southern constellation of Pavo. It was discovered by the English astronomer John Herschel on July 5, 1836. The galaxy is located at a distance of 142 million light years from the Milky Way, and is receding with a heliocentric radial velocity of 3,140 km/s. It does not display any indications of a recent interaction with another galaxy or cluster.
NGC 3726 is a spiral galaxy located in the constellation Ursa Major. It is located at a distance of circa 45 million light years from Earth, which, given its apparent dimensions, means that NGC 3726 is about 85,000 light years across. It was discovered by William Herschel on February 5, 1788.
NGC 7606 is a spiral galaxy located in the constellation Aquarius. It is located at a distance of circa 100 million light years from Earth, which, given its apparent dimensions, means that NGC 7606 is about 165,000 light years across. It was discovered by William Herschel on September 28, 1785. The galaxy is included in the Herschel 400 Catalogue. It lies 45 arcminutes northeast from psi2 Aquarii. It can be seen with a 4 inch telescope but its visibility is greatly affected by light pollution.
NGC 7723 is a barred spiral galaxy located in the constellation Aquarius. It is located at a distance of circa 90 million light years from Earth, which, given its apparent dimensions, means that NGC 7723 is about 95,000 light years across. It was discovered by William Herschel on November 27, 1785. The galaxy is included in the Herschel 400 Catalogue. It lies 1.5 degrees north-northwest from Omega1 Aquarii. It can be seen with a 4-inch telescope under dark skies.
NGC 7184 is a barred spiral galaxy located in the constellation Aquarius. It is located at a distance of circa 100 million light years from Earth, which, given its apparent dimensions, means that NGC 7184 is about 175,000 light years across. It was discovered by William Herschel on October 28, 1783.
NGC 3489 is a lenticular galaxy located in the constellation Leo. It is located at a distance of circa 30 million light years from Earth, which, given its apparent dimensions, means that NGC 3489 is about 30,000 light years across. It was discovered by William Herschel on April 8, 1784. NGC 3489 is a member of the Leo Group.
NGC 1386 is a spiral galaxy located in the constellation Eridanus. It is located at a distance of circa 53 million light years from Earth, which, given its apparent dimensions, means that NGC 1386 is about 50,000 light years across. It is a Seyfert galaxy, the only one in Fornax Cluster.
NGC 7531 is an intermediate spiral galaxy located in the constellation Grus. It is located at a distance of circa 70 million light-years from Earth, which, given its apparent dimensions, means that NGC 7531 is about 95,000 light years across. It was discovered by John Herschel on September 2, 1836.
NGC 680 is an elliptical galaxy located in the constellation Aries. It is located at a distance of circa 120 million light years from Earth, which, given its apparent dimensions, means that NGC 680 is about 100,000 light years across. It was discovered by William Herschel on September 15, 1784.
NGC 4312 is an edge-on unbarred spiral galaxy located about 55 million light-years away in the constellation Coma Berenices. It was discovered by astronomer William Herschel on January 14, 1787. NGC 4312 is a member of the Virgo Cluster and is a LINER galaxy.
NGC 2906 is a spiral galaxy located in the constellation Leo. It is located at a distance of circa 120 million light years from Earth, which, given its apparent dimensions, means that NGC 2906 is about 75,000 light years across. It was discovered by William Herschel on December 28, 1785.
NGC 4324 is a lenticular galaxy located about 85 million light-years away in the constellation Virgo. It was discovered by astronomer Heinrich d'Arrest on March 4, 1862. NGC 4324 has a stellar mass of 5.62 × 1010M☉, and a baryonic mass of 5.88 × 1010M☉. The galaxy's total mass is around 5.25 × 1011M☉. NGC 4324 is notable for having a ring of star formation surrounding its nucleus. It was considered a member of the Virgo II Groups until 1999, when its distance was recalculated and it was placed in the Virgo W Group.
NGC 3435 is a barred spiral galaxy located about 235 million light-years from the Milky Way, and is about 125 000 light-years across. It can be found in the constellation Ursa Major. It was discovered on 9 April 1793 by astronomer William Herschel.