BZ Ursae Majoris

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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
Epoch J2000.0       Equinox J2000.0
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  mas/yr [3]
Dec.: −15.915  mas/yr [3]
Parallax (π)6.4561 ± 0.0441  mas [3]
Distance 505 ± 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
Mass 0.65 [9] [10]   M☉
Radius 6,880 [11]   km
Surface gravity (log g)7.5 [5] [12]   cgs
Temperature 15,000 [5] [12]   K
Rotational velocity (v sin i)200 [5]  km/s
Donor star
Mass 0.13 [6]   M☉
Other designations
BZ UMa, 2MASS J08534416+5748406, PG 0849+580 [13]
Database references
SIMBAD data

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]

Related Research Articles

<span class="mw-page-title-main">W Ursae Majoris</span> Star in the constellation Ursa Major

W Ursae Majoris is the variable star designation for a binary star system in the northern constellation of Ursa Major. It has an apparent visual magnitude of about 7.9, which is too faint to be seen with the naked eye. However, it can be viewed with a small telescope. Parallax measurements place it at a distance of roughly 169 light years (52 parsecs) from Earth.

<span class="mw-page-title-main">Dwarf nova</span> Cataclysmic variable star, consisting of a close binary star system

A dwarf nova, or U Geminorum variable, is one of several types of cataclysmic variable star, consisting of a close binary star system in which one of the components is a white dwarf that accretes matter from its companion. Dwarf novae are dimmer and repeat more frequently than "classical" novae.

<span class="mw-page-title-main">U Geminorum</span> Star in the constellation Gemini

U Geminorum, in the constellation Gemini, is an archetypal example of a dwarf nova. The binary star system consists of a white dwarf closely orbiting a red dwarf. Every few months it undergoes an outburst that greatly increases its brightness. The dwarf nova class of variable stars are often referred to as U Geminorum variables after this star.

<span class="mw-page-title-main">AM Herculis</span> Star in the constellation Hercules

AM Herculis is a binary variable star located in the constellation Hercules. This star, along with the star AN Ursae Majoris, is the prototype for a category of cataclysmic variable stars called polars, or AM Her type stars.

<span class="mw-page-title-main">WZ Sagittae</span> Variable star in the constellation Sagitta

WZ Sagittae is a cataclysmic dwarf nova star system in the constellation Sagitta. It consists of a white dwarf primary being orbited by a low mass companion. The white dwarf is about 0.85 solar masses while the companion is only 0.08 solar masses. This implies that the companion is a spectral class L2 star, although this has yet to be confirmed. The distance to this system has been determined by parallax, yielding a distance of 45.1 parsecs.

<span class="mw-page-title-main">EK Trianguli Australis</span> Star system in the constellation Triangulum Australe

EK Trianguli Australis is a star in the constellation Triangulum Australe. It is a dwarf nova of the SU Ursae Majoris type that officially classified as such in 1980, after the characteristic eruptions of a short eruption and a supereruption were observed in May 1978 and June 1979 respectively. These systems are characterised by frequent eruptions and less frequent supereruptions. The former are smooth, while the latter exhibit short "superhumps" of heightened activity. The distance of the system has been assumed at 180 parsecs from the Solar System, for the donor star. Spectroscopic analysis and calculation gave an estimate of 125 parsecs.

<span class="mw-page-title-main">SX Leonis Minoris</span> Star in the constellation of Leo Minor

SX Leonis Minoris is a dwarf nova of the SU Ursae Majoris type that was first discovered as a 16th magnitude blue star in 1957, before its identity was confirmed as a dwarf nova in 1994. The system consists of a white dwarf and a donor star which orbit around a common centre of gravity every 97 minutes. The white dwarf sucks matter from the other star via its Roche lobe onto an accretion disc which is heated to between 6000 and 10000 K and periodically erupts every 34 to 64 days, reaching magnitude 13.4 in these outbursts and remaining at magnitude 16.8 when quiet. These outbursts can be split into frequent eruptions and less frequent supereruptions. The former are smooth, while the latter exhibit short "superhumps" of heightened activity and last 2.6% longer.

<span class="mw-page-title-main">RZ Gruis</span> Star in the constellation of Grus

RZ Gruis is a nova-like binary system in the constellation Grus composed of a white dwarf and an F-type main-sequence star. It is generally of apparent magnitude of 12.3 with occasional dimming to 13.4. Its components are thought to orbit each other roughly every 8.5 to 10 hours. It belongs to the UX Ursae Majoris subgroup of cataclysmic variable star systems, where material from the donor star is drawn to the white dwarf where it forms an accretion disc that remains bright and outshines the two component stars. The system is around 1,434 light-years away from Earth; or as much as 1,770 light years based on a Gaia parallax.

<span class="mw-page-title-main">TV Corvi</span> Star in the constellation Corvus

TV Corvi, also known as Tombaugh's Star, is a dwarf nova of the SU Ursae Majoris type in the constellation Corvus that was first discovered by accident as a mysterious 12th magnitude star on a plate by Clyde Tombaugh while looking for remote planets on May 25, 1932, before its identity was confirmed as a dwarf nova by David Levy in 1990.

<span class="mw-page-title-main">Superhump</span>

In astronomy, a superhump is a periodic brightness variation in a cataclysmic variable star system, with a period within a few percent of the orbital period of the system.

<span class="mw-page-title-main">SU Ursae Majoris</span> Variable star in the constellation Ursa Major

SU Ursae Majoris, or SU UMa, is a close binary star in the northern circumpolar constellation of Ursa Major. It is a periodic cataclysmic variable that varies in magnitude from a peak of 10.8 down to a base of 14.96. The distance to this system, as determined from its annual parallax shift of 4.53 mas, is 719 light-years. It is moving further from the Earth with a heliocentric radial velocity of +27 km/s.

<span class="mw-page-title-main">LL Andromedae</span> Dwarf nova star in the constellation Andromeda

LL Andromedae is a dwarf nova in the constellation Andromeda, discovered during an outburst in 1979. Its typical apparent visual magnitude is 19.4, but undergoes outbursts events when can reach a peak magnitude of 14.3. Since this magnitude is reached during the most powerful outbursts, while less bright outbursts can occur, it is classified as a SU Ursae Majoris variable.

<span class="mw-page-title-main">V455 Andromedae</span> Dwarf nova star in the constellation Andromeda

V455 Andromedae is a dwarf nova in the constellation Andromeda. It has a typical apparent visual magnitude of 16.5, but reached a magnitude of 8.5 during the only observed outburst.

<span class="mw-page-title-main">UX Ursae Majoris</span> Variable star in the constellation Ursa Major

UX Ursae Majoris is an Algol type binary star system in the northern circumpolar constellation of Ursa Major. It is classified as a nova-like variable star similar to DQ Herculis, although no eruptions have been reported. Since its discovery in 1933, this system has been the subject of numerous studies attempting to determine its properties. The combined apparent visual magnitude of UX UMa ranges from 12.57 down to 14.15. The system is located at a distance of approximately 952 light years from the Sun based on parallax, and is drifting further away with a radial velocity of 112 km/s.

<span class="mw-page-title-main">RZ Leonis Minoris</span> Variable star in the constellation Leo Minor

RZ Leonis Minoris is a cataclysmic variable star system in the northern constellation of Leo Minor. It undergoes frequent outbursts that vary in brightness from an apparent visual magnitude of 14.4 down to 16.8. Based on parallax measurements, this system is located at a distance of approximately 2,160 light years from the Sun.

<span class="mw-page-title-main">SW Ursae Majoris</span> Variable star in the constellation Ursa Major

SW Ursae Majoris is a cataclysmic binary star system in the northern circumpolar constellation of Ursa Major, abbreviated SW UMa. During quiescence it has an apparent visual magnitude of 16.5–17, which is too faint to be visible to the naked eye. Based on parallax measurements, it is located at a distance of approximately 526 light years from the Sun.

<span class="mw-page-title-main">BE Ursae Majoris</span> Variable star in the constellation Ursa Major

BE Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated BE UMa. The two components are an unusual M-class dwarf star and a subdwarf O star, borderline white dwarf. It is classified as a detached Algol variable and ranges in brightness from an apparent visual magnitude of 14.8 down to 17.8. This is too faint to be visible to the naked eye. The distance to this system is approximately 4,600 light years based on parallax measurements.

<span class="mw-page-title-main">DW Ursae Majoris</span> Variable star in the constellation Ursa Major

DW Ursae Majoris is an eclipsing binary star system in the northern circumpolar constellation of Ursa Major, abbreviated DW UMa. It is a cataclysmic variable of the SX Sextanis type, consisting of a compact white dwarf that is accreting matter from an orbiting companion star. The brightness of this source ranges from an apparent visual magnitude of 13.6 down to magnitude 18, which is too faint to be viewed with the naked eye. The distance to this system is approximately 1,920 light years based on parallax measurements.

<span class="mw-page-title-main">ER Ursae Majoris</span> Variable binary star system in the constellation Ursa Major

ER Ursae Majoris is a variable star in the northern circumpolar constellation of Ursa Major, abbreviated ER UMa. It is a prototype system for a subclass of SU Ursae Majoris dwarf novae. The system ranges in brightness from a peak apparent visual magnitude of 12.4 down to 15.2, which is too faint to be visible to the naked eye. The distance to this system, based on parallax measurements, is approximately 1,163 light years.

<span class="mw-page-title-main">CR Boötis</span> Star system in the constellation Boötes

CR Boötis is an interacting binary system in the northern constellation of Boötes, abbreviated CR Boo. It is one of the best-known AM Canum Venaticorum stars. The system varies widely in brightness, ranging in apparent visual magnitude from 13.6 down to 17.5. The distance to this system is approximately 1,150 light years from the Sun, based on parallax measurements.

References

  1. ↑ "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
  2. ↑ Kato, Taichi; et al. (December 2009). "Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae". Publications of the Astronomical Society of Japan. 61: S395–S616. arXiv: 0905.1757 . Bibcode:2009PASJ...61S.395K. doi:10.1093/pasj/61.sp2.S395 . Retrieved 19 June 2022.
  3. 1 2 3 4 5 6 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). 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, arXiv: 1804.02132 , Bibcode:2018AJ....156..241H, doi: 10.3847/1538-3881/aae47f , S2CID   59939788, 241.
  5. 1 2 3 4 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, arXiv: 1107.4790 , Bibcode:2011PASP..123.1071G, doi:10.1086/661763, S2CID   119265399.
  6. 1 2 3 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, Bibcode:1994MNRAS.271..323R, doi: 10.1093/mnras/271.2.323 .
  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, arXiv: 2101.02756 , Bibcode:2021MNRAS.502.5668V, doi: 10.1093/mnras/staa3711 .
  8. 1 2 Szkody, Paula; Feinswog, Laurie (November 1988), "Infrared Light Curves of Three Novae and Three Dwarf Novae at Quiescence", Astrophysical Journal, 334: 422, Bibcode:1988ApJ...334..422S, doi:10.1086/166846.
  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, Bibcode:2019RNAAS...3..185M, doi: 10.3847/2515-5172/ab60ab , S2CID   216539831, 185.
  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, arXiv: 1804.00786 , Bibcode:2018ApJ...853..182Y, doi: 10.3847/1538-4357/aaa47d , S2CID   119364315, 182.
  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, Bibcode:2013NewA...25....1I, doi:10.1016/j.newast.2013.03.011.
  12. 1 2 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, Bibcode:2012JASS...29..169S, doi: 10.5140/JASS.2012.29.2.169 .
  13. ↑ "BZ UMa", SIMBAD , Centre de données astronomiques de Strasbourg , retrieved 2022-03-09.
  14. 1 2 3 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, arXiv: 0909.4024 , Bibcode:2009PASP..121.1205P, doi:10.1086/648479, S2CID   118612829.
  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), vol. 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, Bibcode:1982PASP...94..560G, doi:10.1086/131022, S2CID   120644760.
  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, arXiv: astro-ph/0305264 , Bibcode:2003ApJ...594..443G, doi:10.1086/376902, S2CID   120224177.

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