SW Ursae Majoris

Last updated • 1 min readFrom Wikipedia, The Free Encyclopedia
SW Ursae Majoris
SWUMaLightCurve.png
Light curves for SW Ursae Majoris, adapted from Robinson et al. (1987) [1]
Observation data
Epoch J2000       Equinox J2000
Constellation Ursa Major
Right ascension 08h 36m 42.749s [2]
Declination +53° 28 37.98 [2]
Apparent magnitude  (V)9.7 to 16.5 [3]
Characteristics
Variable type U Gem [3]
Astrometry
Proper motion (μ)RA: −28.713  mas/yr [2]
Dec.: 5.928  mas/yr [2]
Parallax (π)6.2002 ± 0.0602  mas [2]
Distance 526 ± 5  ly
(161 ± 2  pc)
Absolute magnitude  (MV)+4.9 (at maximum) [4]
Details
White dwarf
Mass 0.61+0.06
0.04
[5]   M
Radius 0.0129+0.0009
0.0010
[5]   R
Surface gravity (log g)8.01+0.11
0.09
[5]   cgs
Temperature 13,854+189
131
[5]   K
donor
Mass 0.1 [6]   M
Luminosity0.001 [6]   L
Other designations
SW UMa, 2MASS J08364276+5328378 [7]
Database references
SIMBAD data

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. [8] Based on parallax measurements, it is located at a distance of approximately 526  light years from the Sun. [2]

The variable nature of this object was noted by L. Tseraskaya in 1909 when it increased in brightness to 10th magnitude. [9] [10] It was determined to be a U Geminorum star, indicating this is a binary star system. [11] A short orbital period of 81.8 minutes was determined by A. W. Shafter and associates in 1986. [12] The same year, E. L. Robinson and associates detected superhumps with a period of 84.0 minutes. [1] Large amplitude quasi-periodic oscillations were observed by T. Kato and associates in 1992, which is a property of SU UMa-type dwarf novae. [13]

When the system is in a quiet period, it displays a periodicity of 15.9 minutes and has a marginal emission of soft X-rays. This is likely the rotation period of the white dwarf, and the system resembles an intermediate polar with a strongly-magnetized white dwarf as the accreting component. [8] It undergoes outbursts that vary in brightness and duration. [14] During quiescence, it is estimated that about 70% of the bolometric luminosity of the system is produced by the white dwarf, with almost all the rest produced by the accretion disk. [15]

Related Research Articles

Theta Ursae Majoris is a suspected spectroscopic binary star system in the northern circumpolar constellation of Ursa Major. It has an apparent visual magnitude of 3.17, placing it among the brighter members of this constellation. The distance to this star has been measured directly using the parallax method, yielding an estimated value of 43.96 light-years.

<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">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">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">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>

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">XY Ursae Majoris</span> Eclipsing binary star system in the constellation of Ursa Major

XY Ursae Majoris is a short period binary star system in the northern circumpolar constellation of Ursa Major. It is an eclipsing binary with a baseline apparent visual magnitude of 9.50. The system is located at a distance of 221.5 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −10 km/s. It has a relatively high proper motion, traversing the celestial sphere at the angular rate of 0.191″·yr−1.

<span class="mw-page-title-main">BZ Ursae Majoris</span> Dwarf Nova in the constellation Ursa Major

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. The system is located at a distance of approximately 505 light years from the Sun based on parallax measurements.

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

EQ Tauri is a triple star system in the equatorial constellation of Taurus that includes a contact eclipsing binary. The system is too faint to be viewed with the naked eye, having a baseline apparent visual magnitude of 10.5. During the primary eclipse, the brightness of the system drops to magnitude 11.03, then to 10.97 during the secondary minimum. The secondary eclipse is total. Based on parallax measurements, it is located at a distance of approximately 730 light years from the Sun.

<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">VV Ursae Majoris</span> Variable star system in the constellation Ursa Major

VV Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated VV UMa. It is a variable star system with a brightness that cycles around an apparent visual magnitude of 10.19, making it too faint to be visible to the naked eye. The system is located at a distance of approximately 1,500 light years based on parallax measurements.

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

AW Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated AW UMa. It is an A-type W Ursae Majoris variable with an apparent visual magnitude of 6.83, which is near the lower limit of visibility to the naked eye. This is an eclipsing binary with the brightness dropping to magnitude 7.13 during the primary eclipse and to 7.08 with the secondary eclipse. Parallax measurements give a distance estimate of 221 light years from the Sun. It is drifting closer to the Sun with a radial velocity of approximately −17 km/s. The system has a high proper motion, traversing the celestial sphere at the rate of 0.216 arc second per annum.

<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">DM Ursae Majoris</span> Variable star in the constellation Ursa Major

DM Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated DM UMa. It is sometimes identified by the Bonner Durchmusterung catalogue designation BD +61 1211; DM UMa is the variable star designation. The system has a combined apparent visual magnitude of 9.29, which is too faint to be visible to the naked eye. Based on parallax measurements, the system is located at a distance of approximately 606 light years from the Sun, but it is drifting closer with a heliocentric radial velocity of −7 km/s.

<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. 1 2 Robinson, Edward L.; et al. (February 1987), "Detection of Superhumps and Quasi-periodic Oscillations in the Light Curve of the Dwarf Nova SW Ursae Majoris", Astrophysical Journal, 313: 772, Bibcode:1987ApJ...313..772R, doi:10.1086/165015.
  2. 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.
  3. 1 2 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, S2CID   125853869.
  4. Patterson, Joseph (2011), "Distances and absolute magnitudes of dwarf novae: Murmurs of period bounce", Monthly Notices of the Royal Astronomical Society, 411 (4): 2695–2716, arXiv: 0903.1006 , Bibcode:2011MNRAS.411.2695P, doi: 10.1111/j.1365-2966.2010.17881.x .
  5. 1 2 3 4 Pala, A. F.; et al. (March 2022), "Constraining the evolution of cataclysmic variables via the masses and accretion rates of their underlying white dwarfs", Monthly Notices of the Royal Astronomical Society, 510 (4): 6110–6132, arXiv: 2111.13706 , Bibcode:2022MNRAS.510.6110P, doi:10.1093/mnras/stab3449.
  6. 1 2 Povich, M. S.; et al. (September 24, 2004), "Far Ultraviolet Spectroscopic Explorer Observations of the Dwarf Nova SW Ursae Majoris during Quiescence", arXiv, vol. 617, no. 1, pp. 500–507, arXiv: astro-ph/0409588 , Bibcode:2004ApJ...617..500P, doi:10.1086/425213, S2CID   31384959.
  7. "SW UMa". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2022-09-12.
  8. 1 2 Soejima, Yuichi; et al. (August 2009), "Photometry of Three Superoutbursts of the SU UMa-Type Dwarf Nova, SW Ursae Majoris", Publications of the Astronomical Society of Japan, 61 (4): 659–674, arXiv: 0905.0348 , Bibcode:2009PASJ...61..659S, doi:10.1093/pasj/61.4.659.
  9. Ceraski, W. (December 1909), "Note sur un astre qui est probablement une étoile variable (44.1909 Ursae majoris)", Astronomische Nachrichten (in French), 183 (7): 109, Bibcode:1909AN....183..109C, doi:10.1002/asna.19091830705.
  10. Hornby, P. W. (October 1975), "Two U Geminorum variables: UV Per 1926–69 and SW UMa 1963–69", Journal of the British Astronomical Association, 85: 528–531, Bibcode:1975JBAA...85..528H.
  11. Wellmann, P. (1952), "Lichtkurve und Maximumspektrum des U Geminorum-Veränderlichen SW Ursae maioris. Mit 7 Textabbildungen", Zeitschrift für Astrophysik (in German), 31: 123, Bibcode:1952ZA.....31..123W.
  12. Shafter, A. W.; et al. (September 1986), "X-Ray and Optical Observations of the Ultrashort Period Dwarf Nova SW Ursae Majoris: A Likely New DQ Herculis Star", Astrophysical Journal, 308: 765, Bibcode:1986ApJ...308..765S, doi: 10.1086/164549 .
  13. Kato, Taichi; et al. (October 1992), "Discovery of "Super-Quasi-Periodic Oscillations" during Superoutburst of Dwarf Nova SW Ursae Majoris", Publications of the Astronomical Society of Japan, 44: L215–L219, Bibcode:1992PASJ...44L.215K.
  14. Howell, Steve B.; et al. (November 1995), "Ultraviolet Observations of SW Ursae Majoris, BC Ursae Majoris, and TV Corvi (1217--18): IUE Spectroscopy and Outburst Light Curves", Astrophysical Journal, 453: 454, Bibcode:1995ApJ...453..454H, doi:10.1086/176407.
  15. Urban, Joel A; Sion, Edward M (2006). "The Dwarf Novae during Quiescence". The Astrophysical Journal. 642 (2): 1029–1041. arXiv: astro-ph/0602126 . Bibcode:2006ApJ...642.1029U. doi:10.1086/501430. S2CID   1434460.

Further reading