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BW Vulpeculae

A light curve for BW Vulpeculae, plotted from TESS data
Observation data Epoch J2000      Equinox J2000
Constellation	Vulpecula
Right ascension	20 54 22.39491
Declination	+28° 31′ 19.1827″
Apparent magnitude (V)	6.54 (6.44 – 6.68)
Characteristics
Spectral type	B2 IIIv
U−B color index	−0.147±0.011
Variable type	β Cep
Astrometry
Radial velocity (Rv)	−6.1±3.0 km/s
Proper motion (μ)	RA: +0.437 mas/yr Dec.: −4.981 mas/yr
Parallax (π)	1.1494 ± 0.0652 mas
Distance	2,800 ± 200 ly (870 ± 50 pc)
Absolute magnitude (MV)	−2.47
Details
Mass	6.8±0.1 or 11−14 M☉
Luminosity	515.14 L☉
Surface gravity (log g)	3.71 cgs
Temperature	23,014+919 −883 K
Metallicity	0.07±0.12 dex
Rotational velocity (v sin i)	24±6 km/s
Age	3.4±2.5 Myr
Other designations
AAVSO 2050+28, BW Vul, BD+27° 3909, HD 199140, HIP 103191, HR 8007, SAO 89265
Database references
SIMBAD	data

BW Vulpeculae or BW Vul, is a variable star in the northern constellation of Vulpecula. It is near the lower limit of visibility to the naked eye with a typical apparent visual magnitude of 6.54. Based on an annual parallax shift of 1.15 mas, the distance to BW Vul is about 2,800 light years. It is moving closer to the Earth with a baseline heliocentric radial velocity of around −6 km/s.

This is a B-type giant star with a stellar classification of B2 IIIv, where the 'v' suffix indicates variability in spectral features. Various authors have printed mass estimates ranging from 11 to 14 times the mass of the Sun, although Tetzlaff et al. (2011) gives a mass of just 6.8 M_☉. It is about 3.4 million years old and is spinning with a projected rotational velocity of 24 km/s. The star is typically radiating 515 times the Sun's luminosity from its photosphere at an effective temperature of 23,014 K.

The variability of this star was announced in 1937, at the 58th Meeting of the American Astronomical Society by Canadian astronomer, Robert Methven Petrie. It is a Beta Cephei variable that ranges between magnitudes 6.44 and 6.68 over a period of 4.8 hours. For unknown reasons, the periodicity of the star has undergone sudden changes, followed by long periods of stability. BW Vul is one of the most extreme β Cephei stars in terms of variability of light and radial velocity. This is hypothesized as being due to the star's relatively high metallicity, meaning the abundance of elements other than hydrogen and helium. A distinctive feature of its radial velocity cycle is a unique "standstill" feature, which is caused by a shockwave generated by infall of material from a previous cycle.

References

1. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
2. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
3. ^ Stankov, A.; et al. (September 2003). "Abundances and radial velocity analysis of BW Vulpeculae". Astronomy and Astrophysics. 408 (3): 1077–1086. Bibcode:2003A&A...408.1077S. doi:10.1051/0004-6361:20031005.
4. ^ Otero, Sebastian Alberto (21 November 2011). "BW Vulpeculae". AAVSO Website. American Association of Variable Star Observers. Retrieved 2 August 2015.
5. ^ Lynds, C. R. (September 1959). "The light-variability of early B giants". Astrophysical Journal. 130: 577. Bibcode:1959ApJ...130..577L. doi:10.1086/146747.
6. ^ 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. Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
8. ^ Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
9. Gontcharov, G. A. (November 2012). "Spatial distribution and kinematics of OB stars". Astronomy Letters. 38 (11): 694–706. arXiv:1606.09028. Bibcode:2012AstL...38..694G. doi:10.1134/S1063773712110035. S2CID 119108982.
10. ^ 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.
11. ^ Fokin, A.; et al. (November 2004). "Hydrodynamic models for β Cephei variables. I. BW Vulpeculae revisited". Astronomy and Astrophysics. 426 (2): 687–693. Bibcode:2004A&A...426..687F. doi:10.1051/0004-6361:20040418.
12. ^ Niemczura, E.; Daszyńska-Daszkiewicz, J. (April 2005). "Metallicities of the β Cephei stars from low-resolution ultraviolet spectra". Astronomy and Astrophysics. 433 (2): 659–669. arXiv:astro-ph/0410440. Bibcode:2005A&A...433..659N. doi:10.1051/0004-6361:20040396. S2CID 14295631.. Note: value taken from .
13. "BW Vul". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 7, 2018.
14. Petrie, R. M. (1939). "A new Beta Canis Majoris-type star". Publications of the American Astronomical Society. 9: 53. Bibcode:1939PAAS....9Q..53P.
15. Odell, A. P. (August 2012). "Period variation in BW Vulpeculae redux". Astronomy & Astrophysics. 544: 4. arXiv:1205.5996. Bibcode:2012A&A...544A..28O. doi:10.1051/0004-6361/201219418. S2CID 119279687. A28.
16. ^ Smith, Myron A.; et al. (December 2005). "Far-Ultraviolet and Optical Observations of BW Vulpeculae". The Astrophysical Journal. 634 (2): 1300–1310. Bibcode:2005ApJ...634.1300S. doi:10.1086/497026.

v t e Constellation of Vulpecula
List of stars in Vulpecula Vulpecula in Chinese astronomy
Stars	Bayer α (Anser) Flamsteed 1 2 3 4 5 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 35 3 Cyg Variable R S T U V X Z RS SV VW WW AW BE BO BP BS BW DR ER LT LV MW NQ NR NS PS PU PW PX QQ QR QU QV QY V379 V387 V407 V452 V457 V458 HR 7207 7250 7263 7286 7364 7384 7391 7421 7452 7472 7490 7540 7556 7573 7601 7656 7716 7760 7811 7849 7862 7895 7903 8082 8158 8190 8194 8197 8198 HD 186943 187614 188015 189671 190066 190228 190322 201626 Other ASKAP J1935+2148 BD+23 3912 G 185-32 GD 385 GS 2000+25 HIP 100963 PSR B1919+21 PSR B1930+22 PSR B1937+21 PSR B1953+29 PSR B2020+28 PSR J1946+2052 PSR J2007+2722 Wolf 1346 WR 125 XTE J1859+226 SGR 1935+2154
Exoplanets HD 188015 b HD 189733 b
Star clusters Brocchi's Cluster NGC 6885 NGC 6940
Nebulae Dumbbell Nebula Hen 2-437 Sh2-88
Galaxies	NGC 7052 7080 Other 3C 433
Astronomical events AT 2021lwx
Category

• B-type giants
• Beta Cephei variables
• Vulpecula
• Durchmusterung objects
• Henry Draper Catalogue objects
• Hipparcos objects
• Bright Star Catalogue objects
• Objects with variable star designations