Sculptor Dwarf Irregular | |
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![]() Sculptor Dwarf Irregular Galaxy close up by Hubble Space Telescope. | |
Observation data (J2000 epoch) | |
Constellation | Sculptor |
Right ascension | 00h 08m 13.36s [1] |
Declination | −34° 34′ 42.0″ [1] |
Redshift | 221 ± 6 km/s [2] |
Distance | 10.44 ± 0.33 Mly (3.2 ± 0.1 Mpc) [1] |
Apparent magnitude (V) | 15.5 [2] |
Absolute magnitude (V) | −11.87 [1] |
Characteristics | |
Type | dIrr [1] |
Apparent size (V) | 1.1′ × 0.9′ [2] |
Half-light radius (apparent) | 29″.4 ± 1″.6 [1] |
Other designations | |
SDIG, [2] PGC 621, [2] ESO 349-031 [2] |
The Sculptor Dwarf Irregular Galaxy (SDIG) is an irregular galaxy in the constellation Sculptor. It is a member of the NGC 7793 subgroup of the Sculptor Group. [1] The galaxy was discovered in 1976.[ citation needed ]
The Sculptor Dwarf Irregular Galaxy and the dwarf galaxy UGCA 442 are both companions of the spiral galaxy NGC 7793. [3] These galaxies all lie within the Sculptor Group, a weakly bound, filament-like group of galaxies located near the Local Group. [3]
The Sculptor Group is a loose group of galaxies visible near the south galactic pole. The group is one of the closest groups of galaxies to the Local Group; the distance to the center of the group from the Milky Way is approximately 3.9 Mpc (12.7 Mly).
NGC 300 (also known as Caldwell 70) is a spiral galaxy in the constellation Sculptor. It is one of the closest galaxies to the Local Group, and probably lies between the latter and the Sculptor Group. It is the brightest of the five main spirals in the direction of the Sculptor Group. It is inclined at an angle of 42° when viewed from Earth and shares many characteristics of the Triangulum Galaxy. It is 94,000 light-years in diameter, somewhat smaller than the Milky Way, and has an estimated mass of (2.9 ± 0.2) × 1010M☉.
NGC 55, is a Magellanic type barred spiral galaxy located about 6.5 million light-years away in the constellation Sculptor. Along with its neighbor NGC 300, it is one of the closest galaxies to the Local Group, probably lying between the Milky Way and the Sculptor Group. It has an estimated mass of (2.0 ± 0.4) × 1010M☉.
NGC 404 is a field galaxy located about 10 million light years away in the constellation Andromeda. It was discovered by William Herschel in 1784, and is visible through small telescopes. NGC 404 lies just beyond the Local Group and does not appear gravitationally bound to it. It is located within 7 arc-minutes of second magnitude star Mirach, making it a difficult target to observe or photograph and granting it the nickname "Mirach's Ghost".
The Centaurus A/M83 Group is a complex group of galaxies in the constellations Hydra, Centaurus, and Virgo. The group may be roughly divided into two subgroups. The Cen A Subgroup, at a distance of 11.9 Mly, is centered on Centaurus A, a nearby radio galaxy. The M83 Subgroup, at a distance of 14.9 Mly, is centered on the Messier 83 (M83), a face-on spiral galaxy.
Alpha Sculptoris, Latinized from α Sculptoris, is the Bayer designation for a blue-white star in the southern constellation of Sculptor. It has an apparent visual magnitude of +4.30, which makes it the brightest star in this generally faint constellation. Parallax measurements collected during the Hipparcos mission provide a distance estimate for this star, placing it at roughly 780 light-years, with a 4% margin of error.
Beta Sculptoris, Latinized from β Sculptoris, is a single, blue-white hued star in the southern constellation of Sculptor. It has an apparent visual magnitude of 4.37, which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 18.74 mas as seen from Earth, it is located 174 light years from the Sun.
Gamma Sculptoris, Latinized from γ Sculptoris, is a single, orange-hued star in the constellation Sculptor. Based upon an annual parallax shift of 17.90 mas as seen from Earth, this star is located about 182 light years from the Sun. It is bright enough to be visible to the naked eye with an apparent visual magnitude of 4.41. It is moving away from the Sun with a radial velocity of +15.6 km/s.
Delta Sculptoris is a triple star system in the constellation Sculptor. It is approximately 137.4 light years from Earth.
ι Sculptoris, Latinized as Iota Sculptoris and abbreviated iot Scl, is a solitary star in the southern constellation of Sculptor. It is visible to the naked eye as a dim, orange-hued point of light with an apparent visual magnitude of 5.18. The star is located approximately 336 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +21 km/s.
π Sculptoris, Latinized as Pi Sculptoris, is candidate astrometric binary star system in the southern constellation Sculptor, positioned near the eastern constellation border with Fornax. It has an orange hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.25. Based upon parallax measurements, the system is located at a distance of 66 light years from the Sun, and is drifting further away with a radial velocity of +14 km/s.
Xi Sculptoris, Latinized from ξ Sculptoris, is a solitary orange-hued star in the southern constellation of Sculptor, near the southern constellation boundary with Phoenix. It is just visible to the naked eye as a dim point of light with an apparent visual magnitude of 5.59. The distance to Xi Sculptoris is approximately 489 light years based on parallax, while it is drifting closer with a radial velocity of −31 km/s. It has an absolute magnitude of −0.39.
Lambda1 Sculptoris, Latinised from λ1 Sculptoris, is a double star system in the southern constellation of Sculptor. It is close to the lower limit of visibility to the naked eye, with a combined apparent visual magnitude of +6.05. Based upon an annual parallax shift of 6.89 mas as measured from Earth, it is located roughly 470 light-years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.026 due to interstellar dust.
NGC 7793 is a flocculent spiral galaxy in the southern constellation of Sculptor. It was discovered in 1826 by Scottish astronomer James Dunlop. The galaxy is located at a distance of 12.2 million light years and is receding with a heliocentric radial velocity of 227 km/s. NGC 7793 is one of the five brightest galaxies within the Sculptor Group.
WD 0137-349 is a binary star in the constellation of Sculptor. It is located about 330 light-years away, and appears exceedingly faint with an apparent magnitude of 15.33.
NGC 278 is an isolated spiral galaxy in the northern circumpolar constellation of Cassiopeia, near the southern constellation boundary with Andromeda. It lies at a distance of approximately 39 megalight-years from the Milky Way, giving it a physical scale of 190 ly (58 pc) per arcsecond. The galaxy was discovered on December 11, 1786 by German-born astronomer William Herschel. J. L. E. Dreyer described it as, "considerably bright, pretty large, round, 2 stars of 10th magnitude near".
NGC 247 is an intermediate spiral galaxy about 11.1 Mly away in the constellation Cetus. This distance was confirmed in late February 2011. Previous measurements showed that the galaxy was about 12.2 Mly away, but this was proved to be wrong. NGC 247 is a member of the Sculptor Group, and is 70 000 light years in diameter.
Gliese 42 is a star in the southern constellation of Sculptor. It is too faint to be seen with the naked eye, having an apparent visual magnitude of +7.3. The annual parallax shift of 70.56 mas provides a distance estimate of 46 light years. It has a relatively high proper motion, advancing 0.62 arcseconds across the sky per annum, and is moving closer to the Sun with a radial velocity of −13 km/s.
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 3311 is a supergiant elliptical galaxy located about 190 million light-years away in the constellation Hydra. The galaxy was discovered by astronomer John Herschel on March 30, 1835. NGC 3311 is the brightest member of the Hydra Cluster and forms a pair with NGC 3309 which along with NGC 3311, dominate the central region of the Hydra Cluster.