Astronomy:V4381 Sagittarii

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Short description: Star in the constellation Sagittarius
V4381 Sagittarii
V4381SgrLightCurve.png
A light curve for V4381 Sagittarii, plotted from Hipparcos data[1]
Observation data
Equinox J2000.0]] (ICRS)
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[2] mas
Distanceapprox. 1,400 ly
(approx. 400 pc)
Absolute magnitude (MV)−6.6[6]
Details
Mass7.00[7] M☉
Luminosity39,000[3] L☉
Surface gravity (log g)1.50[3] cgs
Temperature9,000[3] K
Rotational velocity (v sin i)18[3] km/s
Age43.3[7] Myr
Other designations
V4381 Sagittarii, HD 165784, HIP 88876, BD−21°4866, 2MASS J18083858-2126584
Database references
SIMBADdata

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]

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,[12] while Gaia Early Data Release 3, based on optical astrometry, have resulted in measured parallax 0.6273±0.0372.[13]

References

  1. ↑ "Hipparcos Tools Interactive Data Access". ESA. https://www.cosmos.esa.int/web/hipparcos/interactive-data-access. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Firnstein, M.; Przybilla, N. (2012). "Quantitative spectroscopy of Galactic BA-type supergiants. I. Atmospheric parameters". Astronomy & Astrophysics 543: A80. doi:10.1051/0004-6361/201219034. Bibcode: 2012A&A...543A..80F. 
  4. ↑ 4.0 4.1 Samus, N. N. 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. 
  5. ↑ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G. 
  6. ↑ Humphreys, R. M. (1978). "Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way". Astrophysical Journal 38: 309. doi:10.1086/190559. Bibcode: 1978ApJS...38..309H. 
  7. ↑ 7.0 7.1 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. doi:10.1111/j.1365-2966.2010.17434.x. Bibcode: 2011MNRAS.410..190T. 
  8. ↑ Magakian, T. Yu. (2003). "Merged catalogue of reflection nebulae". Astronomy and Astrophysics 399: 141–145. doi:10.1051/0004-6361:20021743. Bibcode: 2003A&A...399..141M. 
  9. ↑ Van Den Bergh, S. (1966). "A study of reflection nebulae". Astronomical Journal 71: 990. doi:10.1086/109995. Bibcode: 1966AJ.....71..990V. 
  10. ↑ 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. doi:10.1051/0004-6361:20078525. Bibcode: 2008A&A...477..165P. 
  11. ↑ 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. doi:10.1051/0004-6361/201322302. Bibcode: 2013A&A...558A..53K. 
  12. ↑ 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, doi:10.3847/1538-4357/aabba6, Bibcode: 2018ApJ...859...14X 
  13. ↑ Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.

External links



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