 A light curve for V4381 Sagittarii, plotted from Hipparcos data | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18 08 38.58558 |
| Declination | −21° 26′ 58.4136″ |
| Apparent magnitude (V) | 6.538 (6.57p - 6.62p) |
| Characteristics | |
| Evolutionary stage | Supergiant |
| Spectral type | A2 Iab |
| U−B color index | +0.279 |
| B−V color index | +0.856 |
| Variable type | α Cyg |
| Astrometry | |
| Radial velocity (Rv) | −16 km/s |
| Proper motion (μ) | RA: −1.65 mas/yr Dec.: −1.05 mas/yr |
| Parallax (π) | 2.25 ± 0.55 mas |
| Distance | approx. 1,400 ly (approx. 400 pc) |
| Absolute magnitude (MV) | −6.6 |
| Details | |
| Mass | 7.00 M☉ |
| Luminosity | 39,000 L☉ |
| Surface gravity (log g) | 1.50 cgs |
| Temperature | 9,000 K |
| Rotational velocity (v sin i) | 18 km/s |
| Age | 43.3 Myr |
| Other designations | |
| V4381 Sagittarii, HD 165784, HIP 88876, BD−21°4866, 2MASS J18083858-2126584 | |
| 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. It was first listed as VdB 113 and described as possibly associated with a loose open cluster. 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. 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.
Distance estimations
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, while Gaia Early Data Release 3, based on optical astrometry, have resulted in measured parallax 0.6273±0.0372.
References
- "Hipparcos Tools Interactive Data Access". Hipparcos. ESA. Retrieved 8 December 2021.
- ^ Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
- ^ Firnstein, M.; Przybilla, N. (2012). "Quantitative spectroscopy of Galactic BA-type supergiants. I. Atmospheric parameters". Astronomy & Astrophysics. 543: A80. arXiv:1207.0308. Bibcode:2012A&A...543A..80F. doi:10.1051/0004-6361/201219034. S2CID 54725386.
- ^ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
- Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
- Humphreys, R. M. (1978). "Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way". Astrophysical Journal. 38: 309. Bibcode:1978ApJS...38..309H. doi:10.1086/190559.
- ^ Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. S2CID 118629873.
- Magakian, T. Yu. (2003). "Merged catalogue of reflection nebulae". Astronomy and Astrophysics. 399: 141–145. Bibcode:2003A&A...399..141M. doi:10.1051/0004-6361:20021743.
- Van Den Bergh, S. (1966). "A study of reflection nebulae". Astronomical Journal. 71: 990. Bibcode:1966AJ.....71..990V. doi:10.1086/109995.
- Piskunov, A. E.; Schilbach, E.; Kharchenko, N. V.; Röser, S.; Scholz, R.-D. (2008). "Tidal radii and masses of open clusters". Astronomy and Astrophysics. 477 (1): 165–172. Bibcode:2008A&A...477..165P. doi:10.1051/0004-6361:20078525.
- Kharchenko, N. V.; Piskunov, A. E.; Schilbach, E.; Röser, S.; Scholz, R.-D. (2013). "Global survey of star clusters in the Milky Way. II. The catalogue of basic parameters". Astronomy & Astrophysics. 558: A53. arXiv:1308.5822. Bibcode:2013A&A...558A..53K. doi:10.1051/0004-6361/201322302. S2CID 118548517.
- Xu, Shuangjing; Zhang, Bo; Reid, Mark J.; Menten, Karl M.; Zheng, Xingwu; Wang, Guangli (2018), "The Parallax of the Red Hypergiant VX SGR with Accurate Tropospheric Delay Calibration", The Astrophysical Journal, 859 (1): 14, arXiv:1804.00894, Bibcode:2018ApJ...859...14X, doi:10.3847/1538-4357/aabba6, S2CID 55572194
- Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
External links
- Image of VdB 113 V4381 Sgr is the upper of the two bright white stars.
- WEBDA page for vdBergh 113 V4381 Sgr is the brightest star
- Drawing of VdB 113 Archived 2016-11-11 at the Wayback Machine
