Astronomy:V4024 Sagittarii
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[2] 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 | |
| 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
- ↑ "/ftp/cats/more/HIP/cdroms/cats". Strasbourg astronomical Data Center. https://cdsarc.cds.unistra.fr/viz-bin/ftp-index?/ftp/cats/more/HIP/cdroms/cats.
- ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 Samus, N. N. et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1 61 (1): 80–88. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S.
- ↑ 4.0 4.1 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. doi:10.1051/0004-6361:20011202. Bibcode: 2001A&A...378..861C.
- ↑ 6.0 6.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ 7.0 7.1 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, doi:10.1051/0004-6361/201628760, Bibcode: 2016A&A...595A.132Z
- ↑ 8.0 8.1 Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics 367 (2): 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P.
- ↑ 9.0 9.1 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, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T.
- ↑ "HD 178175". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+178175.
- ↑ 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. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E.
- ↑ Mason, Brian D. (November 1996). "ICCD Speckle Observations of Binary Stars. XV. An Investigation of Lunar Occultation Systems". Astronomical Journal 112: 2260. doi:10.1086/118179. Bibcode: 1996AJ....112.2260M.
- ↑ 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. https://articles.adsabs.harvard.edu/pdf/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. Bibcode: 1978IBVS.1414....1K. https://articles.adsabs.harvard.edu/pdf/1978IBVS.1414....1K. Retrieved 28 September 2025.
- ↑ 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. doi:10.1046/j.1365-8711.2002.05150.x. Bibcode: 2002MNRAS.331...45K.
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