Astronomy:20 Vulpeculae

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Short description: Star in the constellation Vulpecula
20 Vulpeculae
Observation data
Equinox J2000.0]] (ICRS)
Constellation Vulpecula
Right ascension  20h 12m 00.70176s[1]
Declination +26° 28′ 43.6989″[1]
Apparent magnitude (V) 5.91[2]
Characteristics
Evolutionary stage main sequence[3]
Spectral type B7 Ve[4][5]
B−V color index −0.107±0.003[2]
Astrometry
Radial velocity (Rv)−22.0±4.3[2] km/s
Proper motion (μ) RA: +4.096[1] mas/yr
Dec.: −9.524[1] mas/yr
Parallax (π)2.7904 ± 0.0726[1] mas
Distance1,170 ± 30 ly
(358 ± 9 pc)
Absolute magnitude (MV)−2.13[2]
Details
Mass4.02±0.14[3] M
Radius3.0[6] R
Luminosity460+88
−74
[3] L
Surface gravity (log g)2.90[7] cgs
Temperature12,050+168
−165
[3] K
Rotational velocity (v sin i)236[3] km/s
Other designations
20 Vul, BD+26°3828, HD 192044, HIP 99531, HR 7719, SAO 88339[8]
Database references
SIMBADdata

20 Vulpeculae is single[5] star located around 1,170[1] light years away in the northern constellation of Vulpecula.[8] It is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude of 5.91.[2] The object is moving closer to the Earth with a heliocentric radial velocity of −22 km/s.[2]

This is a Be star with a stellar classification of B7 Ve.[4] It is spinning rapidly with a projected rotational velocity of 236 km/s (compared to a critical velocity of 332 km/s)[3] and has an estimated polar inclination of 71.1°.[9] The star has four times the mass of the Sun and is radiating around 460 times the Sun's luminosity from its photosphere at an effective temperature of 12,050 K.[3]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Zorec, J. et al. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy and Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, Bibcode2012A&A...537A.120Z. 
  4. 4.0 4.1 Antoniou, A. et al. (2011), "Studying the UV mg II Resonance Lines in 20 Be Stars", Baltic Astronomy 20 (4): 572–575, doi:10.1515/astro-2017-0338, Bibcode2011BaltA..20..572A. 
  5. 5.0 5.1 Eggleton, P. P.; Tokovinin, A. A. (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, Bibcode2008MNRAS.389..869E. 
  6. Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics 367: 521–524, doi:10.1051/0004-6361:20000451, Bibcode2001A&A...367..521P. 
  7. 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, Bibcode2001A&A...378..861C, http://ri.conicet.gov.ar/bitstream/11336/36962/2/CONICET_Digital_Nro.da657706-52b0-4788-843c-67c34222e14c_A.pdf. 
  8. 8.0 8.1 "20 Vulpeculae". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=20+Vulpeculae. 
  9. Frémat, Y.; Zorec, J.; Hubert, A.-M.; Floquet, M. (2005), "Effects of gravitational darkening on the determination of fundamental parameters in fast-rotating B-type stars", Astronomy and Astrophysics 440 (1): 305, doi:10.1051/0004-6361:20042229, Bibcode2005A&A...440..305F. 

External links