2 Vulpeculae

2 Vulpeculae is a binary star[10] system in the northern constellation of Vulpecula, located around 1,200 light years away from the Sun. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 5.43.[2]

2 Vulpeculae
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Vulpecula
Right ascension  19h 17m 43.63655s[1]
Declination +23° 01′ 31.9524″[1]
Apparent magnitude (V) 5.43[2]
Characteristics
Spectral type B1 IV[3]
B−V color index 0.020±0.003[2]
Variable type β Cep[4]
Astrometry
Radial velocity (Rv)+1.0±4.2[2] km/s
Proper motion (μ) RA: +2.04[1] mas/yr
Dec.: −2.78[1] mas/yr
Parallax (π)2.68 ± 0.36[1] mas
Distanceapprox. 1,200 ly
(approx. 370 pc)
Absolute magnitude (MV)−2.35[2]
Details
Mass12.5±0.6[5] M☉
Luminosity (bolometric)21,922[6] L☉
Temperature26,850[6] K
Metallicity [Fe/H]−0.06±0.10[7] dex
Rotational velocity (v sin i)270[8] km/s
Age12.6±0.7[5] Myr
Other designations
2 Vul, ES Vul, BD+22°3648, HD 180968, HIP 94827, HR 7318, SAO 87036, WDS 19177+2302[9]
Database references
SIMBADdata

2 Vulpeculae is a double-lined spectroscopic binary;[10] as of 2002, the pair had an angular separation of 1.72″ along a position angle of 127.2°.[11]

The primary component of the binary is a rapidly rotating Be star[12] with a stellar classification of B1 IV.[3] It is a variable star with an amplitude of 0.06 magnitude and a period of 0.6096 days, tentatively classified as Beta Cephei variable.[4] The variability was discovered in 1959,[13] and it has been assigned the variable star designation ES Vulpeculae.[4]

References
  1. van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  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.
  3. Rountree, Janet; Sonneborn, George (1991). "Criteria for the spectral classification of B stars in the ultraviolet". Astrophysical Journal. 369: 515. Bibcode:1991ApJ...369..515R. doi:10.1086/169781.
  4. 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.
  5. Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (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.
  6. Hohle, M. M.; et al. (2010). "Masses and luminosities of O- and B-type stars and red supergiants". Astronomische Nachrichten. 331 (4): 349–360. arXiv:1003.2335. Bibcode:2010AN....331..349H. doi:10.1002/asna.200911355.
  7. Gáspár, András; et al. (2016). "The Correlation between Metallicity and Debris Disk Mass". The Astrophysical Journal. 826 (2): 171. arXiv:1604.07403. Bibcode:2016ApJ...826..171G. doi:10.3847/0004-637X/826/2/171.
  8. Abt, Helmut A.; et al. (July 2002). "Rotational Velocities of B Stars". The Astrophysical Journal. 573 (1): 359–365. Bibcode:2002ApJ...573..359A. doi:10.1086/340590.
  9. "2 Vul". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-03-12.
  10. Chini, R.; et al. (2012). "A spectroscopic survey on the multiplicity of high-mass stars". Monthly Notices of the Royal Astronomical Society. 424 (3): 1925–1929. arXiv:1205.5238. Bibcode:2012MNRAS.424.1925C. doi:10.1111/j.1365-2966.2012.21317.x.
  11. Roberts, Lewis C., Jr. (May 2011). "Astrometric and photometric measurements of binary stars with adaptive optics: observations from 2002". Monthly Notices of the Royal Astronomical Society. 413 (2): 1200–1205. arXiv:1012.3383. Bibcode:2011MNRAS.413.1200R. doi:10.1111/j.1365-2966.2011.18205.x.
  12. Balona, L. A. (December 1995). "Tests of the Pulsation and Starspot Models for the Periodic Be-Stars". Monthly Notices of the Royal Astronomical Society. 277 (4): 1547. Bibcode:1995MNRAS.277.1547B. doi:10.1093/mnras/277.4.1547.
  13. Lynds, C. R. (1959). "The Light-Variability of Early B Giants". The Astrophysical Journal. 130: 577. Bibcode:1959ApJ...130..577L. doi:10.1086/146747.

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