V4024 Sagittarii

A light curve for V4024 Sagittarii, plotted from Hipparcos data[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Sagittarius
Right ascension 19h 08m 16.70187s[2]
Declination −19° 17′ 25.0380″[2]
Apparent magnitude (V) 5.34 - 5.60[3]
Characteristics
Spectral type B2Ve[4]
B−V color index −0.06[5]
Variable type γ Cas[3]
Astrometry
Radial velocity (Rv)−20.3±2.9[6] km/s
Proper motion (μ) RA: +6.240[2] mas/yr
Dec.: −1.126[2] mas/yr
Parallax (π)2.3734 ± 0.1406 mas[2]
Distance1,370 ± 80 ly
(420 ± 20 pc)
Absolute magnitude (MV)−2.39[6]
Details[7]
Mass8.8±0.6 M☉
Radius4.5[8] R☉
Luminosity (bolometric)7,551+1,119
−974 L☉
Surface gravity (log g)3.24±0.49 cgs
Temperature18,100±500 K
Rotational velocity (v sin i)105±10 km/s
Age25.1±1.3[9] Myr
Other designations
V4024 Sgr, BD−19°5312, HD 178175, HIP 93996, HR 7249, SAO 162229[10]
Database references
SIMBADdata

V4024 Sagittarii is a single[11] variable star in the southern constellation of Sagittarius. It has a blue-white hue and is dimly visible to the naked eye with an apparent visual magnitude that fluctuates from about 5.3 to 5.6. The star is located at a distance of approximately 1,700 light years based on stellar parallax, but is drifting closer with a radial velocity of −20 km/s. The position of this star near the ecliptic means it is subject to lunar occultations.[12]

This object is a massive Be star with a stellar classification of B2Ve.[4] The 'e' suffix indicates the spectrum of the star displays emission lines, which are created by materials ejected from the equatorial region of this rapidly rotating star. It is classified as an eruptive Gamma Cassiopeiae variable and has been measured ranging in brightness from visual magnitude 5.34 down to 5.60.[3] The star is an estimated 5 million years old with 8.8 times the mass of the Sun[9] and about 4.5[8] times the Sun's radius. It is spinning with a projected rotational velocity of 105 m/s. V4024 Sagittarii is radiating 7,551 times the luminosity of the Sun from its photosphere at an effective temperature of 18,100 K.[7] Koen and Eyer examined the Hipparcos data for this star, and found that its brightness varied with a period of 1.7733 days.[13]

References

  1. ↑ "/ftp/cats/more/HIP/cdroms/cats". Centre de Données astronomiques de Strasbourg. Strasbourg astronomical Data Center. Retrieved 15 October 2022.
  2. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 3 Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
  4. 1 2 Jaschek, C.; Jaschek, M. (November 1992). "A southern Be star survey: Spectra and envelope radii". Astronomy and Astrophysics Supplement Series. 95 (3): 535–540. Bibcode:1992A&AS...95..535J.
  5. ↑ Chauville, J.; et al. (November 2001). "High and intermediate-resolution spectroscopy of Be stars 4481 lines". Astronomy and Astrophysics. 378: 861–882. Bibcode:2001A&A...378..861C. doi:10.1051/0004-6361:20011202.
  6. 1 2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  7. 1 2 Zorec, J.; et al. (November 2016), "Critical study of the distribution of rotational velocities of Be stars. I. Deconvolution methods, effects due to gravity darkening, macroturbulence, and binarity", Astronomy & Astrophysics, 595: 26, Bibcode:2016A&A...595A.132Z, doi:10.1051/0004-6361/201628760
  8. 1 2 Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics (Third ed.), 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
  9. 1 2 Tetzlaff, N.; et al. (January 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.
  10. ↑ "HD 178175". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-02-21.
  11. ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
  12. ↑ Mason, Brian D. (November 1996). "ICCD Speckle Observations of Binary Stars. XV. An Investigation of Lunar Occultation Systems". Astronomical Journal. 112: 2260. Bibcode:1996AJ....112.2260M. doi:10.1086/118179.
  13. ↑ Koen, Chris; Eyer, Laurent (March 2002). "New periodic variables from the Hipparcos epoch photometry". Monthly Notices of the Royal Astronomical Society. 331 (1): 45–59. Bibcode:2002MNRAS.331...45K. doi:10.1046/j.1365-8711.2002.05150.x. S2CID 10505995.
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