Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Carina |
Right ascension | 11h 15m 7.645s [1] |
Declination | −61° 15′ 17.61″ [1] |
Apparent magnitude (V) | 12.23 [2] |
Characteristics | |
Spectral type | B1Iab [2] |
U−B color index | 0.13 [3] |
B−V color index | 1.42 [3] |
Variable type | cLBV [4] |
Astrometry | |
Proper motion (μ) | RA: −5.387 [1] mas/yr Dec.: +2.116 [1] mas/yr |
Parallax (π) | 0.1560 ± 0.0166 mas [1] |
Distance | 17,700±2,300 ly (5,440±700 pc) [5] |
Absolute magnitude (MV) | −7.05±0.34 [5] |
Details [5] | |
Mass | 25.5±1.7 M☉ |
Radius | 42±7 R☉ |
Luminosity (bolometric) | 308,000+115,000 −83,000 L☉ |
Surface gravity (log g) | 2.61±0.06 cgs |
Temperature | 20,900±500 K |
Rotational velocity (v sin i) | 60±5 km/s |
Age | 7.24+0.70 −0.64 Myr |
Other designations | |
Sher 25, NGC 3603-25, NGC 3603 MTT 13, NGC 3603 MDS 5 | |
Database references | |
SIMBAD | data |
Sher 25 is a blue supergiant star in the constellation Carina, located approximately 25,000 light years from the Sun in the H II region NGC 3603 of the Milky Way. [6] It is a spectral type B1Iab star with an apparent magnitude of 12.2. [7] Its initial main sequence mass is calculated at 60 times the mass of the Sun, but a star of this type will have already lost a substantial fraction of that mass. It is unclear whether Sher 25 has been through a red supergiant phase or has just evolved from the main sequence, so the current mass is very uncertain. [8]
The name derives from the original cataloguing of stars in NGC 3603 by David Sher. This catalogue entry is more fully referred to as NGC 3603 Sher 25 to distinguish it from stars potentially numbered 25 by Sher in other clusters (eg. NGC 3766). [9] The same star was numbered 13 by Melnick, Tapia, and Terlevich [3] (MTT 13) and 5 in a Hubble Space Telescope survey by Moffat, Drissen, and Shara [10] (NGC 3603 MDS 5).
It is speculated that Sher 25 is near the point of exploding as a supernova, as it has recently thrown off matter in a pattern similar to that of supernova 1987A in the Large Magellanic Cloud, with a circumstellar ring and bipolar outflow filaments. [4]
Regular variations in the doppler shift of the star's spectral lines with a period of a few days may be due to orbital motion about a companion star, or to pulsations of the star's surface. [11]
Scutum is a small constellation. Its name is Latin for shield, and it was originally named Scutum Sobiescianum by Johannes Hevelius in 1684. Located just south of the celestial equator, its four brightest stars form a narrow diamond shape. It is one of the 88 IAU designated constellations defined in 1922.
NGC 3603 is a nebula situated in the Carina–Sagittarius Arm of the Milky Way around 20,000 light-years away from the Solar System. It is a massive H II region containing a very compact open cluster HD 97950.
Mu Cephei, also known as Herschel's Garnet Star, Erakis, or HD 206936, is a red supergiant or hypergiant star in the constellation Cepheus. It appears garnet red and is located at the edge of the IC 1396 nebula. Since 1943, the spectrum of this star has served as a spectral standard by which other stars are classified.
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.
Phi Cassiopeiae is a multiple star in the constellation Cassiopeia with a combined apparent magnitude of +4.95. The two brightest components are A and C, sometimes called φ1 and φ2 Cas. φ Cas A is an F0 bright supergiant of magnitude 4.95 and φ Cas C is a 7.08 magnitude B6 supergiant at 134".
NGC 3293 is an open cluster in the Carina constellation. It was discovered by Nicolas-Louis de Lacaille in 1751. It consists of more than 100 stars brighter than 14th magnitude in a 10 arc minute field, the brightest of which are blue supergiants of apparent magnitude 6.5 and 6.7. There is also a 7th magnitude pulsating red supergiant, V361 Carinae.
MY Cephei is a red supergiant located in open cluster NGC 7419 in the constellation of Cepheus. It is a semiregular variable star with a maximum brightness of magnitude 14.4 and a minimum of magnitude 15.5.
Kappa Crucis is a spectroscopic binary star in the open cluster NGC 4755, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster.
4U 1700-37 is one of the stronger binary X-ray sources in the sky, and is classified as a high-mass X-ray binary. It was discovered by the Uhuru satellite. The "4U" designation refers to the fourth Uhuru catalog.
S Persei is a red supergiant or hypergiant located near the Double Cluster in Perseus, north of the cluster NGC 869. It is a member of the Perseus OB1 association and one of the largest known stars. If placed in the Solar System, its photosphere would engulf the orbit of Jupiter. It is also a semiregular variable, a star whose variations are less regular than those of Mira variables.
U Lacertae is a spectroscopic binary star in the constellation Lacerta.
DU Crucis is a red supergiant and slow irregular variable star in the open cluster NGC 4755, which is also known as the Kappa (κ) Crucis Cluster or Jewel Box Cluster.
NGC 4424 is a spiral galaxy located in the equatorial constellation of Virgo. It was discovered February 27, 1865 by German astronomer Heinrich Louis d'Arrest. This galaxy is located at a distance of 13.5 million light years and is receding with a heliocentric radial velocity of 442 km/s. It has a morphological class of SB(s)a, which normally indicates a spiral galaxy with a barred structure (SB), no inner ring feature (s), and tightly-wound spiral arms (a). The galactic plane is inclined at an angle of 62° to the line of sight from the Earth. It is a likely member of the Virgo Cluster of galaxies.
NGC 4349 is an open cluster in the constellation Crux. It was discovered by James Dunlop in 1826. It is located approximately 7,000 light years away from Earth.
IX Carinae is a red supergiant and pulsating variable star of spectral type M2Iab in the constellation Carina. It is a member of the Carina OB1 association along the Carina Nebula.
NGC 7419 is an open cluster in the constellation Cepheus. It is heavily reddened and notable for containing five red supergiants, the highest number known in any cluster until the end of the 20th century, but probably no blue supergiants.
Westerlund 1-20 (abbreviated to Wd 1-20 or just W20) is a red supergiant (RSG) located in the Westerlund 1 super star cluster. Its radius was calculated to be around 965 solar radii (6.72 × 108 km, 4.48 au), making it one of the largest stars discovered so far. This corresponds to a volume 899 million times bigger than the Sun. If placed at the center of the Solar System, the photosphere of Westerlund 1-20 would almost reach the orbit of Jupiter.
MTT 68 is a multiple star system located on the outskirts of the HD 97950 cluster in the NGC 3603 star-forming region, about 25,000 light years from Earth. It contains a rare example of an O2If* star which is one of the most luminous and most massive known.