Astronomy:BZ Ursae Majoris

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Short description: Dwarf Nova in the constellation Ursa Major
BZ Ursae Majoris
BZUMaLightCurve.png
A visual band light curve for BZ Ursae Majoris. The main plot (from AAVSO data[1]) shows several outbursts, and the inset plot (adapted from Kato et al.[2]) shows a single superoutburst in detail.
Observation data
Equinox J2000.0]] (ICRS)
Constellation Ursa Major
Right ascension  08h 53m 44.174s[3]
Declination +57° 48′ 40.59″[3]
Apparent magnitude (V) 15.7 to 16.5[4]
10.2 to 15.9[5]
Characteristics
Spectral type M5.5:Ve[6]
Variable type SU UMa[7]
Astrometry
Proper motion (μ) RA: 26.318[3] mas/yr
Dec.: −15.915[3] mas/yr
Parallax (π)6.4561 ± 0.0441[3] mas
Distance505 ± 3 ly
(155 ± 1 pc)
Orbit[6]
Period (P)97.8±0.1 h
Inclination (i)~60[8]°
Periastron epoch (T)2,448,319.897±0.003 HJD
Details
White dwarf
Mass0.65[9][10] M☉
Radius6,880[11] km
Surface gravity (log g)7.5[5][12] cgs
Temperature15,000[5][12] K
Rotational velocity (v sin i)200[5] km/s
Donor star
Mass0.13[6] M☉
Other designations
BZ UMa, 2MASS J08534416+5748406, PG 0849+580[13]
Database references
SIMBADdata

BZ Ursae Majoris is a dwarf nova star system in the northern circumpolar constellation of Ursa Major. It consists of a white dwarf primary in a close orbit with a red dwarf. The latter star is donating mass, which is accumulating in an accretion disk orbiting the white dwarf.[14] The system is located at a distance of approximately 505 light years from the Sun based on parallax measurements.[3]

This system was discovered to vary in brightness by B. E. Markaryan in 1968,[15] and it was given the variable star designation BZ UMa.[16] After four years of observation by the AAVSO, it was proposed to be a cataclysmic variable by M. Mayall.[14] In 1982, R. F. Green and associates identified it as a cataclysmic variable candidate of the U Gem-type, based on its spectrum.[17] The same year, W. Wenzel showed that this star had very long intervals between outbursts, placing it intermediate between the U Gem and WZ Sge classes.[18] P. Szkody and L. Feinswog examined the infrared light curve of the system, estimating an orbital inclination of 60° with no evidence of heating from the white dwarf.[8]

R. Claudi and associates in 1990 found a periodic modulation of hydrogen emission lines, indicating an orbital period of 1.62 h. They suggested it be classified as a SU UMa star.[19] Spectroscopic examination of the system using the Hubble Space Telescope during 2001 showed an anomalous abundance ratio of nitrogen to carbon that indicates CNO-processing.[20] This may be the result of an earlier evolutionary stage of the donor star that was stripped of its outer layers. A superoutburst was observed in 2007 that displayed superhumps. A lack of circular polarization indicates the white dwarf is not strongly magnetic, and thus this system is most likely not an intermediate polar.[14]

References

  1. ↑ "Download Data". AAVSO. https://www.aavso.org/data-download. 
  2. ↑ Kato, Taichi (December 2009). "Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae". Publications of the Astronomical Society of Japan 61: S395–S616. doi:10.1093/pasj/61.sp2.S395. Bibcode: 2009PASJ...61S.395K. https://ui.adsabs.harvard.edu/abs/2009PASJ...61S.395K. Retrieved 19 June 2022. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  4. ↑ Heinze, A. N. et al. (November 2018), "A First Catalog of Variable Stars Measured by the Asteroid Terrestrial-impact Last Alert System (ATLAS)", The Astronomical Journal 156 (5): 49, doi:10.3847/1538-3881/aae47f, 241, Bibcode: 2018AJ....156..241H. 
  5. ↑ 5.0 5.1 5.2 5.3 Godon, Patrick et al. (September 2011), "A Far-Ultraviolet Spectroscopic Analysis of BZ Ursae Majoris", Publications of the Astronomical Society of the Pacific 123 (907): 1071, doi:10.1086/661763, Bibcode: 2011PASP..123.1071G. 
  6. ↑ 6.0 6.1 6.2 Ringwald, F. A. et al. (November 1994), "Orbital studies of the cataclysmic variables CZ Orionis, V1193 Orionis and BZ Ursae Majoris", Monthly Notices of the Royal Astronomical Society 271 (2): 323–342, doi:10.1093/mnras/271.2.323, Bibcode: 1994MNRAS.271..323R. 
  7. ↑ Vogt, N. et al. (April 2021), "Determination of the superoutburst cycle lengths of 206 SU UMa-type dwarf novae", Monthly Notices of the Royal Astronomical Society 502 (4): 5668–5678, doi:10.1093/mnras/staa3711, Bibcode: 2021MNRAS.502.5668V. 
  8. ↑ 8.0 8.1 Szkody, Paula; Feinswog, Laurie (November 1988), "Infrared Light Curves of Three Novae and Three Dwarf Novae at Quiescence", Astrophysical Journal 334: 422, doi:10.1086/166846, Bibcode: 1988ApJ...334..422S. 
  9. ↑ Maccarone, Thomas J.; Arur, Kavitha (December 2019), "On the Mass of the White Dwarf in BZ UMa", Research Notes of the American Astronomical Society 3 (12): 185, doi:10.3847/2515-5172/ab60ab, 185, Bibcode: 2019RNAAS...3..185M. 
  10. ↑ Yu, Zhuo-li et al. (February 2018), "An Empirical Correlation of T max-M WD of Dwarf Novae and the Average White Dwarf Mass in Cataclysmic Variables in the Galactic Bulge", The Astrophysical Journal 853 (2): 8, doi:10.3847/1538-4357/aaa47d, 182, Bibcode: 2018ApJ...853..182Y. 
  11. ↑ İkis Gün, G. et al. (December 2013), "Preliminary results of the spectral analysis of Suzaku data of SW Ursae Majoris and BZ Ursae Majoris", New Astronomy 25: 1–6, doi:10.1016/j.newast.2013.03.011, Bibcode: 2013NewA...25....1I. 
  12. ↑ 12.0 12.1 Sion, Edward M. (June 2012), "White Dwarfs in Cataclysmic Variable Stars: Surface Temperatures and Evolution", Journal of Astronomy and Space Sciences 29 (2): 169–173, doi:10.5140/JASS.2012.29.2.169, Bibcode: 2012JASS...29..169S. 
  13. ↑ "BZ UMa". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=BZ+UMa. 
  14. ↑ 14.0 14.1 14.2 Price, A. et al. (November 2009), "Polarimetry and the Long-Awaited Superoutburst of BZ UMa", Publications of the Astronomical Society of the Pacific 121 (885): 1205, doi:10.1086/648479, Bibcode: 2009PASP..121.1205P. 
  15. ↑ Neustroev, V. V. et al. (July 2004), Tovmassian, G.; E., Sion, eds., "New spectroscopic observations of dwarf nova BZ Ursae Majoris with extremely unusual emission lines profiles", Compact Binaries in the Galaxy and Beyond, Proceedings of the conference held 17-22 November, 2003 in La Paz, Baja California Sur, IAU Colloquium 194, Revista Mexicana de Astronomía y Astrofísica (Serie de Conferencias) 20: p. 269, Bibcode: 2004RMxAC..20..269N. 
  16. ↑ Kukarkin, B. V. et al. (October 1970), "57th Name-List of Variable Stars", Information Bulletin on Variable Stars 480 (1): 1, Bibcode: 1970IBVS..480....1K. 
  17. ↑ Green, R. F.; Ferguson, D. H.; Liebert, J.; Schmidt, M. (June 1982), "Cataclysmic variable candidates from the Palomar Green Survey", Publications of the Astronomical Society of the Pacific 94: 560–564, doi:10.1086/131022, Bibcode: 1982PASP...94..560G. 
  18. ↑ Wenzel, W. (December 1982), "BZ Ursae Majoris - Missing Link Between the Dwarf Novae of U Geminorum and WZ Sagittae Type", Information Bulletin on Variable Stars 2256 (1): 1, Bibcode: 1982IBVS.2256....1W. 
  19. ↑ Claudi, R. et al. (March 1990), Green, D. W. E., ed., "BZ Ursae Majoris", IAU Circular 4975 (2): 2, Bibcode: 1990IAUC.4975....2C. 
  20. ↑ Gänsicke, Boris T. et al. (September 2003), "Anomalous Ultraviolet Line Flux Ratios in the Cataclysmic Variables 1RXS J232953.9+062814, CE 315, BZ Ursae Majoris, and EY Cygni, Observed with the Hubble Space Telescope Space Telescope Imaging Spectrograph", The Astrophysical Journal 594 (1): 443–448, doi:10.1086/376902, Bibcode: 2003ApJ...594..443G. 

Further reading

  • Sion, E. M.; Godon, P. (2012), "White dwarfs in cataclysmic variable stars: accretion physics and evolution", Memorie della Societa Astronomica Italiana 83: 539, Bibcode: 2012MmSAI..83..539S. 
  • Jiang, L. L. et al. (January 2010), "The Photometry of Cataclysmic Variable V1159 Ori and BZ UMa", Acta Astronomica Sinica 51 (1): 42–53, Bibcode: 2010AcASn..51...42J. 
  • Price, A. et al. (May 2004), "Flickering and Periodic Activity in the 2004 Outburst of BZ UMa", Information Bulletin on Variable Stars 5526 (1): 1, Bibcode: 2004IBVS.5526....1P. 
  • Kato, T. (September 1999), "CCD Photometry of the 1999 March Outburst of BZ UMa: Detection of Quasi-Periodic Oscillations", Information Bulletin on Variable Stars 4768 (1): 1, Bibcode: 1999IBVS.4768....1K. 
  • Jurcevic, J. S. et al. (May 1994), "Spectroscopy and Photometry of the Dwarf Nova BZ UMa and the CV Line-Width/K, Mass-Ratio Relation", Publications of the Astronomical Society of the Pacific 106: 481, doi:10.1086/133403, Bibcode: 1994PASP..106..481J. 
  • Ringwald, F. A.; Thorstensen, J. R. (September 1990), "Quasi-Periodic Variation in the Radial Velocity Curve of the Dwarf Nova BZ UMa", Bulletin of the American Astronomical Society 22: 1291, Bibcode: 1990BAAS...22.1291R. 




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