DW Ursae Majoris

A light curve for DW Ursae Majoris, plotted from TESS data[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Ursa Major
Right ascension 10h 33m 52.875s[2]
Declination +58° 46′ 54.72″[2]
Apparent magnitude (V) 13.6 to 18.0[3]
Characteristics
Spectral type M7±2.0[4]
Variable type Algol variable[5]
Astrometry
Proper motion (μ) RA: 0.974 mas/yr[2]
Dec.: 1.396 mas/yr[2]
Parallax (π)1.6958 ± 0.0196 mas[2]
Distance1,920 ± 20 ly
(590 ± 7 pc)
Orbit
Period (P)3.2785566 h[3]
Semi-major axis (a)1.14±0.06 R☉[4]
Inclination (i)82±4[4]°
Details
White dwarf
Mass0.77±0.07[4] M☉
Radius0.012±0.001[4] R☉
Surface gravity (log g)8[4] (assumed) cgs
Temperature50,000±1,000[4] K
Red dwarf
Mass0.25±0.05[6] M☉
Radius0.34±0.04[4] R☉
Other designations
PG 1030+590, DW UMa, GSC 03822-00464, 2MASS J10335283+5846547[7]
Database references
SIMBADdata

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.[8] The brightness of this source ranges from an apparent visual magnitude of 13.6 down to magnitude 18,[5] 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.[2]

In 1982, R. F. Green and associates identified this star as a cataclysmic variable candidate with the Palomar–Green survey designation PG 1030+590.[9] A. W. Shafter and F. V. Hessman in 1984 found this to be a close eclipsing binary system with a period of 3.27 hours.[10] This is a nova-like binary where mass is being transferred from a late-type star to a white dwarf companion. This material is first accumulated in an accretion disk orbiting the white dwarf. Typically, the light curve for an eclipsing binary of this type should display a hump-like feature from where the stream of material interacts with the disk. However, during early observations, no such feature was observed before the eclipse.[11]

The behavior of the emission lines in the spectrum of this star were found to resemble those of other SW Sextantis variables.[12] In 2000, the system was observed with the Hubble Space Telescope and was found to be in a low state about three magnitudes fainter, unlike previous observations where it had been in a high state. Comparison of the ultraviolet spectrum in the two states suggested that the accretion disk is self-eclipsing and it can obscure the view of the white dwarf.[8] The light output of the system undergoes a 13.6 year cycle of variation, probably because of precession of the accretion disk. Both positive and negative superhumps are observed that vary over time in a complex fashion. Mass is being transferred from the donor star at a rate of about 10−8 M☉·yr−1.[6]

References

  1. ^ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, retrieved 16 October 2022.
  2. ^ a b c d e 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. ^ a b "DW UMa", International Variable Star Index, AAVSO, retrieved 2022-10-14.
  4. ^ a b c d e f g h Araujo-Betancor, S.; et al. (January 2003), "The System Parameters of DW Ursae Majoris", The Astrophysical Journal, 583 (1): 437–445, arXiv:astro-ph/0209542, Bibcode:2003ApJ...583..437A, doi:10.1086/345098, S2CID 119468510.
  5. ^ a b 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.
  6. ^ a b Boyd, D. R. S.; et al. (April 2017), "A 16-yr photometric campaign on the eclipsing novalike variable DW Ursae Majoris", Monthly Notices of the Royal Astronomical Society, 466 (3): 3417–3433, arXiv:1612.06883, Bibcode:2017MNRAS.466.3417B, doi:10.1093/mnras/stw3327.
  7. ^ "DW UMa". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2022-10-01.
  8. ^ a b Knigge, Christian; et al. (August 2000), "A Self-occulting Accretion Disk in the SW Sextantis Star DW Ursae Majoris", The Astrophysical Journal, 539 (1): L49–L53, arXiv:astro-ph/0004329, Bibcode:2000ApJ...539L..49K, doi:10.1086/312825, S2CID 18612919.
  9. ^ Green, R. F.; et al. (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.
  10. ^ Shafter, A. W.; Hessman, F. V. (1984), "Time resolved spectroscopy and photometry of a new eclipsing cataclysmic variable, PG 1030+590", Bulletin of the American Astronomical Society, 16: 505, Bibcode:1984BAAS...16R.505S.
  11. ^ Szkody, Paula (October 1987), "Time-Resolved IUE Studies of Cataclysmic Variables. I. Eclipsing Systems of IP Peg, PG 1030 + 590, and V1315 AQL", Astronomical Journal, 94: 1055, Bibcode:1987AJ.....94.1055S, doi:10.1086/114540.
  12. ^ Thorstensen, John R.; et al. (August 1991), "A Spectroscopic Study of the Eclipsing Cataclysmic Binary Star PG0818+513: A Puzzling Novalike Variable", Astronomical Journal, 102: 683, Bibcode:1991AJ....102..683T, doi:10.1086/115902.

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