| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 19h 08m 16.70187s |
| Declination | −19° 17′ 25.0380″ |
| 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 mas/yr Dec.: −1.126 mas/yr |
| Parallax (π) | 2.3734±0.1406 mas |
| Distance | 1,370 ± 80 ly (420 ± 20 pc) |
| Absolute magnitude (MV) | −2.39[6] |
| Details[7] | |
| Mass | 8.8±0.6 M☉ |
| Radius | 4.5[8] R☉ |
| Luminosity (bolometric) | 7,551+1,119 −974 L☉ |
| Surface gravity (log g) | 3.24±0.49 cgs |
| Temperature | 18,100±500 K |
| Rotational velocity (v sin i) | 105±10 km/s |
| Age | 25.1±1.3[9] Myr |
| Other designations | |
| V4024 Sgr, BD−19°5312, HD 178175, HIP 93996, HR 7249, SAO 162229 | |
| Database references | |
| SIMBAD | data |
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. While conducting a photometric study of cepheid variable stars during 1961 and 1962, Johanna Helena Walraven et al. used the star, then known as HD 178175, as a standard star and discovered that its brightness varies.[13] It was given its variable star designation, V4024 Sagittarri, in 1978.[14] 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.[15]
References
[edit]- ↑ "/ftp/cats/more/HIP/cdroms/cats". Centre de Données astronomiques de Strasbourg. Strasbourg astronomical Data Center. Retrieved 15 October 2022.
- 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.
- 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.
- ↑ 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. hdl:11336/36962.
- 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.
- 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, hdl:11336/37946
- 1 2 Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (2) (Third ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
- 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.
- ↑ 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.
- ↑ 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.
- ↑ Walraven, J. H.; Tinbergen, J.; Walraven, Th. (June 1964). "Five-colour observations of 24 classical Cepheids". Bulletin of the Astronomical Institutes of the Netherlands. 17: 520–537. Bibcode:1964BAN....17..520W. Retrieved 28 September 2025.
- ↑ Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (April 1978). "63rd Name-List of Variable Stars". Information Bulletin on Variable Stars: 1–10. :.
- Koen, Chris; Eyer, Laurent (March 2002). . . (1): 59. :. Bibcode:2002MNRAS.331...45K. doi:10.1046/j.1365-8711.2002.05150.x. S2CID 10505995.
