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]
References
^ abRobinson, 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.
^ abcdPala, 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.
^ abSoejima, 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.
^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.
^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.
^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.
^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.
^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.
Perez-Garcia, I.; et al. (October 2021), "Observations with the BOOTES Network of the current outburst in the dwarf-nova SW UMa", The Astronomer's Telegram, 14960: 1, Bibcode:2021ATel14960....1P.
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.
Waagen, E. O.; et al. (September 2006), Green, D. W. E. (ed.), "SW Ursae Majoris", IAU Circular, vol. 8748, p. 2, Bibcode:2006IAUC.8748....2W.
Pavlenko, E. P.; et al. (October 2000), "CCD Photometry of the Cataclysmic Variable SW Ursae Majoris at a Late Stage of the 2000 Superoutburst", Astrophysics (English translation of Astrofizika), vol. 43, no. 4, pp. 419–429, Bibcode:2000Ap.....43..419P, doi:10.1023/A:1010914924206, S2CID117641368.
Mattei, J. A.; et al. (February 2000), Green, D. W. E. (ed.), "SW Ursae Majoris", IAU Circular, vol. 7365, p. 2, Bibcode:2000IAUC.7365....2M.
Gänsicke, B. T.; Koester, D. (June 1999), "SW Ursae Majoris, CU Velorum and AH Mensae: three more accreting white dwarfs unveiled?", Astronomy and Astrophysics, 346: 151–157, Bibcode:1999A&A...346..151G.
Nogami, Daisaku; et al. (April 1998), "CCD Photometry of SW Ursae Majoris during the 1996 Superoutburst", Publications of the Astronomical Society of Japan, 50 (2): 297–302, Bibcode:1998PASJ...50..297N, doi:10.1093/pasj/50.2.297.
Mobberley, M. P.; et al. (April 1997), "C. R. d'Esterre and the mysteries of UV and UW Per", Journal of the British Astronomical Association, 107 (2): 65–71, Bibcode:1997JBAA..107...65M.
Semeniuk, I.; et al. (January 1997), "CCD Photometry of SW Ursae Majoris during the 1996 Superoutburst", Acta Astronomica, 47: 201–209, arXiv:astro-ph/9704215, Bibcode:1997AcA....47..201S.
Szkody, Paula; et al. (May 1988), "EXOSAT and IUE Observations of SW UMa during Superoutburst", Astrophysical Journal, 328: 243, Bibcode:1988ApJ...328..243S, doi:10.1086/166286.