Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Sagittarius |
Right ascension | 18h 08m 38.58558s [2] |
Declination | −21° 26′ 58.4136″ [2] |
Apparent magnitude (V) | 6.538 [3] (6.57p - 6.62p [4] ) |
Characteristics | |
Evolutionary stage | Supergiant [3] |
Spectral type | A2 Iab [3] |
U−B color index | +0.279 [3] |
B−V color index | +0.856 [3] |
Variable type | α Cyg [4] |
Astrometry | |
Radial velocity (Rv) | −16 [5] km/s |
Proper motion (μ) | RA: −1.65 [2] mas/yr Dec.: −1.05 [2] mas/yr |
Parallax (π) | 2.25 ± 0.55 mas [2] |
Distance | approx. 1,400 ly (approx. 400 pc) |
Absolute magnitude (MV) | −6.6 [6] |
Details | |
Mass | 7.00 [7] M☉ |
Luminosity | 39,000 [3] L☉ |
Surface gravity (log g) | 1.50 [3] cgs |
Temperature | 9,000 [3] K |
Rotational velocity (v sin i) | 18 [3] km/s |
Age | 43.3 [7] Myr |
Other designations | |
Database references | |
SIMBAD | data |
V4381 Sagittarii is a variable star in the constellation Sagittarius. A white supergiant of spectral type A2/A3Iab, it is an Alpha Cygni variable that varies between apparent photographic magnitudes 6.57 and 6.62. Its visual apparent magnitude is about 6.54.
V4381 Sagittarii is associated with a small reflection and emission nebula, although it is not actually seen within the nebulosity. The nebula is catalogued as GN 18.05.6. [8] It was first listed as VdB 113 and described as possibly associated with a loose open cluster. [9] That name has since been used for the cluster itself, which is much more distant than the distance of V4381 Sagittarii derived from its Hipparcos parallax. [10] The whole cluster is less than a quarter of a degree across, with dozens of members from 8th magnitude downwards. V4381 Sagittarii is listed as a probable member, while the nearby bright stars HD 165516 and WR 111 are considered unlikely to be members. [11]
The distance to V4381 remains poorly determined as of 2021. The 2018 research based on radio interferometry has measured 2.2±0.6 milliarcseconds parallax, [12] while Gaia Early Data Release 3, based on optical astrometry, have resulted in measured parallax 0.6273±0.0372. [13]
W Sagittarii is a multiple star system star in the constellation Sagittarius, and a Cepheid variable star.
Tau Sagittarii is a star in the southern zodiac constellation of Sagittarius.
X Sagittarii is a variable star and candidate binary star system in the southern constellation of Sagittarius, near the western constellation boundary with Ophiuchus. It has a yellow-white hue and is visible to the naked eye with an apparent visual magnitude that fluctuates around 4.54. The star is located at a distance of approximately 950 light years from the Sun based on parallax, and is drifting closer with a radial velocity of −10 km/s. The star has an absolute magnitude of around −2.85.
Psi Sagittarii, which is Latinized from ψ Sagittarii, is a triple star system in the zodiac constellation of Sagittarius. The star system is located at a distance of 298 light years from the Earth based on parallax, but is drifting closer with a heliocentric radial velocity of −12 km/s. The system is faintly visible to the naked eye has a combined apparent visual magnitude of +4.86.
KW Sagittarii is a red supergiant, located approximately 1,900 parsecs away from the Sun in the direction of the constellation Sagittarius. It is one of the largest-known stars. If placed at the center of the Solar System, the star's surface would engulf Mars.
HD 156768 is a double star in the southern constellation of Ara, with a combined apparent magnitude of 5.86. The brighter component is a sixth magnitude bright giant or supergiant star with a stellar classification of G8Ib/II. The magnitude 9.6 companion lies at an angular separation of 1.81″ along a position angle of 184°.
HD 165516 is a blue supergiant star in the constellation Sagittarius. It is part of the Sagittarius OB1 association and appears against a rich Milky Way starfield near the Triffid Nebula and Lagoon Nebula.
4 Sagittarii is a suspected astrometric binary star system in the zodiac constellation of Sagittarius, located approximately 390 light years away based on parallax. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.74, The system is moving closer to the Earth with a heliocentric radial velocity of −18 km/s.
HD 168607 is a blue hypergiant and luminous blue variable (LBV) star located in the constellation of Sagittarius, easy to see with amateur telescopes. It forms a pair with HD 168625, also a blue hypergiant and possible luminous blue variable, that can be seen at the south-east of M17, the Omega Nebula.
43 Sagittarii is a single star in the southern constellation of Sagittarius. It has the Bayer designation d Sagittarii, while 43 Sagittarii is the Flamsteed designation. This object is visible to the naked eye as a faint, yellow-hued star with an apparent visual magnitude of 4.88. From parallax measurements, it is estimated to lie around 470 light years away from the Sun. The star is drifting further from the Earth with a heliocentric radial velocity of +15.2 km/s. It is located near the ecliptic and thus is subject to lunar occultations.
V1073 Scorpii is a variable star in the constellation Scorpius. It has a non-Greek Bayer designation of k Scorpii. The star has a blue-white hue and is visible to the naked eye with an apparent visual magnitude that fluctuates around +4.87. Parallax measurements yield a distance estimate of approximately 2,920 ly (896 pc) from the Sun, and it is drifting further away with a radial velocity of +7 km/s. It has an absolute magnitude of −6.8
V3903 Sagittarii is an eclipsing binary star system in the constellation Sagittiarus. It creates an H II region LBN 29 1,070 parsecs away from the Sun.
V520 Persei is a blue supergiant member of NGC 869, one of the Perseus Double Cluster open clusters. It is an irregular variable star. At a magnitude of 6.55, V520 Persei is the brightest member in either NGC 869 or NGC 884, although the brighter HD 13994 lies in the foreground along the same line of sight.
HR 4887 is a suspected variable star in the open cluster NGC 4755, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster.
DS Crucis is a variable star near the open cluster NGC 4755, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster. It is in the constellation Crux.
BU Crucis is a variable star in the open cluster NGC 4755, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster.
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.
HD 182681 is a single, blue-hued star in the zodiac constellation of Sagittarius. It has an apparent visual magnitude of +5.64, which is bright enough to be visible to the naked eye in good conditions. Based upon an annual parallax shift of 14.0013 mas as seen from Earth, this star is located around 233 light years from the Sun. It is moving away from the Sun with a radial velocity of 1.40 km/s.
U Sagittarii is a variable star in the southern constellation of Sagittarius, abbreviated U Sgr. It is a classical Cepheid variable that ranges in brightness from an apparent visual magnitude of 6.28 down to 7.15, with a pulsation period of 6.745226 days. At its brightest, this star is dimly visible to the naked eye. The distance to this star is approximately 2,080 light years based on parallax measurements, and it is drifting further away with a radial velocity of 2 km/s.
RS Sagittarii is an eclipsing binary star system in the southern constellation of Sagittarius, abbreviated RS Sgr. It is a double-lined spectroscopic binary with an orbital period of 2.416 days, indicating that the components are too close to each other to be individually resolved. The system has a combined apparent visual magnitude of 6.01, which is bright enough to be faintly visible to the naked eye. During the primary eclipse the brightness drops to magnitude 6.97, while the secondary eclipse is of magnitude 6.28. The distance to this system is approximately 1,420 light years based on parallax measurements.