XY Ursae Majoris

A light curve for XY Ursae Majoris, plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Major
Right ascension 09h 09m 55.935s[2]
Declination +54° 29′ 17.72″[2]
Apparent magnitude (V) 9.50[3]
Characteristics
Evolutionary stage Main sequence
Spectral type G2V + K5V[4]
B−V color index 0.765±0.039[3]
Variable type Detached eclipsing binary, RS CVn[5]
Astrometry
Radial velocity (Rv)−9.98±0.83[6] km/s
Proper motion (μ) RA: −49.781 mas/yr[2]
Dec.: −182.641 mas/yr[2]
Parallax (π)14.7223 ± 0.0137 mas[2]
Distance221.5 ± 0.2 ly
(67.92 ± 0.06 pc)
Absolute magnitude (MV)5.41[3]
Orbit[7]
Period (P)0.4789961 d
Semi-major axis (a)3.05±0.01 R☉[8]
Eccentricity (e)0.0
Inclination (i)79.81[8]°
Periastron epoch (T)2,453,821.6344±0.0002
Semi-amplitude (K1)
(primary)		124.74±0.28 km/s
Details
Primary
Mass1.01±0.01[8] M☉
Radius1.22±0.01[8] R☉
Luminosity1.10±0.02[8] L☉
Temperature5,780[4] K
Secondary
Mass0.65±0.01[8] M☉
Radius0.58±0.01[8] R☉
Luminosity0.09±0.01[8] L☉
Temperature3,850[4] K
Other designations
XY UMa, AG+54 702, BD+55 1317, HD 237786, HIP 44998, SAO 27143, PPM 32024[9]
Database references
SIMBADdata

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.[3] The system is located at a distance of 221.5 light years from the Sun based on parallax measurements,[2] but is drifting closer with a radial velocity of −10 km/s.[6] It has a relatively high proper motion, traversing the celestial sphere at the angular rate of 0.191″·yr−1.[10]

The variability of this system was discovered by W. Strohmeier and its period was determined by R. Kippenhahn, with the findings announced in 1955.[11] It was found to be a detached eclipsing binary system, and by 1963 a variable primary component had been noted.[12] E. H. Geyer made intermittent light curve studies of the system starting with its discovery up until 1975,[11] ascribing variability in the light curve to star spot activity on the primary component. The orbital period of the pair was determined to be 0.479 d,[13] with the orbital plane inclined at an angle of 79.84° to the line of sight from the Earth.[8]

By 1990, enough data had been collected to identify a long term variation of the period, and it was hypothesized this was caused by a third body in the system orbiting the close binary.[14] The orbital period of this component was estimated to be ~30 years in 2001,[15] then refined to 26.7 years by 2010. If the orbital plane of this component is the same as the inner pair, its mass would be 18% of the mass of the Sun. An alternative solution to the period change suggests magnetic activity causes shifts in the angular momentum of the system, but this is considered less likely.[8]

This is a double-lined spectroscopic binary star system with an orbital period of 11.5 h.[7] The primary component is a G-type main-sequence star with a stellar classification of G2V.[4] It is an RS Canum Venaticorum-type variable that is magnetically active[5] and a bright X-ray source.[16] Despite this, relatively few optical flares have been observed.[16] The cooler secondary is a K-type main-sequence star of class K5V that is smaller and less massive than the primary.[4]

References

  1. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  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 3 4 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  4. 1 2 3 4 5 Lister, T. A.; et al. (October 2001), "Starspot distributions on XY UMa during 1997-2000 from eclipse mapping", Monthly Notices of the Royal Astronomical Society, 326 (4): 1489–1498, Bibcode:2001MNRAS.326.1489L, doi:10.1111/j.1365-2966.2001.04712.x.
  5. 1 2 Samus', N. N; et al. (2017), "General catalogue of variable stars", Astronomy Reports, GCVS 5.1, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  6. 1 2 Karataș, Yüksel; et al. (2004), "Kinematics of chromospherically active binaries and evidence of an orbital period decrease in binary evolution", Monthly Notices of the Royal Astronomical Society, 349 (3): 1069–1092, arXiv:astro-ph/0404219, Bibcode:2004MNRAS.349.1069K, doi:10.1111/j.1365-2966.2004.07588.x, S2CID 15290475.
  7. 1 2 Pribulla, Theodor; et al. (May 2007), "Radial Velocity Studies of Close Binary Stars. XII", The Astronomical Journal, 133 (5): 1977–1987, arXiv:astro-ph/0611875, Bibcode:2007AJ....133.1977P, doi:10.1086/512772.
  8. 1 2 3 4 5 6 7 8 9 10 Yuan, Jinzhao (May 2010), "Period Variation and Asymmetry Light Curves of XY Ursae Majoris", The Astronomical Journal, 139 (5): 1801–1807, Bibcode:2010AJ....139.1801Y, doi:10.1088/0004-6256/139/5/1801.
  9. ↑ "XY UMa", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-03-03.
  10. ↑ Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal, 129 (3): 1483–1522, arXiv:astro-ph/0412070, Bibcode:2005AJ....129.1483L, doi:10.1086/427854, S2CID 2603568.
  11. 1 2 Geyer, E. H. (1976), Eggleton, P.; et al. (eds.), "Starspot Activities as an Interpretation for the Light Curve Changes of the Close Binary Star XY UMA", Structure and Evolution of Close Binary Systems; Proceedings of the Symposium, Cambridge, England, July 28-August 1, 1975, Dordrecht: D. Reidel Publishing Co., vol. 73, no. 73, p. 313, Bibcode:1976IAUS...73..313G. Symposium sponsored by the International Astronomical Union.{{citation}}: CS1 maint: postscript (link)
  12. ↑ Lorenzi, L.; Scaltriti, F. (1977), "The variable light-curve of the eclipsing binary XY UMa", Acta Astronomica, 27: 273–279, Bibcode:1977AcA....27..273L.
  13. ↑ Geyer, E. H. (May 1977), "Remarks on Erratic Period Fluctuations of Detached Close Binaries and the Constancy of the Orbital Period of XY UMa", Astrophysics and Space Science, 48 (1): 137–144, Bibcode:1977Ap&SS..48..137G, doi:10.1007/BF00643045, S2CID 120596800.
  14. ↑ Pojmanski, G.; Geyer, E. H. (1990), "The period behaviour of the spotted binary XY UMa", Acta Astronomica, 40: 245, Bibcode:1990AcA....40..245P.
  15. ↑ Pribulla, T.; et al. (June 2001), "An active binary XY UMa revisited", Astronomy and Astrophysics, 371 (3): 997–1011, Bibcode:2001A&A...371..997P, doi:10.1051/0004-6361:20010459.
  16. 1 2 Gong, Hang; et al. (August 2016), "Three X-ray flares near primary eclipse of the RS CVn binary XY UMa", Research in Astronomy and Astrophysics, 16 (8): 014, arXiv:1605.09262, Bibcode:2016RAA....16..131G, doi:10.1088/1674-4527/16/8/131, S2CID 118443682, 131.

Further reading

  • Sowell, James R.; et al. (October 2001), "Period Changes in Four Short-Period Spotted Binaries: UV Piscium, YY Geminorum, CG Cygni, and XY Ursae Majoris", The Astronomical Journal, 122 (4): 1965–1973, Bibcode:2001AJ....122.1965S, doi:10.1086/323091, S2CID 121917917.
  • Yeates, C. M.; et al. (August 2000), "Times of Minimum Light for XY Ursae Majoris", Information Bulletin on Variable Stars, 4943 (1): 1, Bibcode:2000IBVS.4943....1Y.
  • Kjurkchieva, D.; et al. (February 2000), "Multicolour high-speed photometry and Hα spectroscopy of XY UMa", Astronomy and Astrophysics, 354: 909–914, Bibcode:2000A&A...354..909K.
  • Arévalo, M. J.; Lázaro, C. (August 1999), "Time-resolved Spectroscopy of RS Canum Venaticorum Short-Period Systems. II. RT Andromedae, WY Cancri, and XY Ursae Majoris", The Astronomical Journal, 118 (2): 1015–1033, Bibcode:1999AJ....118.1015A, doi:10.1086/300952, S2CID 121443644.
  • Chochol, D.; et al. (December 1998), "The RS CVn binary XY UMa as a member of a triple system", Astronomy and Astrophysics, 340: 415–418, Bibcode:1998A&A...340..415C.
  • Pojmanski, G. (December 1998), "Orbital Solutions for Three RS CVn Systems: WY Cnc, SV Cam and XY UMa", Acta Astronomica, 48: 711–727, Bibcode:1998AcA....48..711P.
  • Jeffries, R. D. (April 1998), "A ROSAT observation of the eclipsing binary system XY UMa", Monthly Notices of the Royal Astronomical Society, 295 (4): 825–833, Bibcode:1998MNRAS.295..825J, doi:10.1046/j.1365-8711.1998.01272.x.
  • Erdem, A.; Gudur, N. (January 1998), "The orbital period study and photometric analysis of XY Ursae Majoris", Astronomy and Astrophysics Supplement, 127 (2): 257–267, Bibcode:1998A&AS..127..257E, doi:10.1051/aas:1998348.
  • Pojmanski, G.; Udalski, A. (October 1997), "An Orbital Solution for RS CVn Binary Star XY UMa", Acta Astronomica, 47: 451–466, Bibcode:1997AcA....47..451P.
  • Collier Cameron, A.; Hilditch, R. W. (May 1997), "Eclipse mapping of starspots on XY UMa in 1992 and 1995", Monthly Notices of the Royal Astronomical Society, 287 (3): 567–574, Bibcode:1997MNRAS.287..567C, doi:10.1093/mnras/287.3.567.
  • Jeffries, R. D.; et al. (December 1995), "V-Band Photometry of XY UMa in 1993 and 1995", Information Bulletin on Variable Stars, 4277 (1): 1, Bibcode:1995IBVS.4277....1J.
  • Hilditch, R. W.; Bell, S. A. (April 1994), "High Precision Photometry of the RS-Canum Binary System XY-Ursae and a Dark-Zone Photometric Model", Monthly Notices of the Royal Astronomical Society, 267 (4): 1081, Bibcode:1994MNRAS.267.1081H, doi:10.1093/mnras/267.4.1081.
  • Rainger, P. P.; et al. (January 1991), "Spectroscopic observations of the RS CVn-type binary systems SV Cam and XY UMa", Monthly Notices of the Royal Astronomical Society, 248: 168, Bibcode:1991MNRAS.248..168R, doi:10.1093/mnras/248.1.168.
  • Geyer, E. H. (1991), "On the long term variability of the chromospheric active close binary XY Ursae Majoris", Astronomische Gesellschaft Abstract Series, 6: 79, Bibcode:1991AGAb....6...79G.
  • Zeilik, M.; et al. (October 1990), "1990 BVR Photometry of XY UMa", Information Bulletin on Variable Stars, 3535 (1): 1, Bibcode:1990IBVS.3535....1Z.
  • Arévalo, M. J.; Lázaro, C. (July 1990), "Infrared Photometry of XY-Ursae", Astrophysics and Space Science, 169 (1–2): 247–249, Bibcode:1990Ap&SS.169..247A, doi:10.1007/BF00640725, S2CID 116674010.
  • Bedford, D. K.; et al. (April 1990), "Coronal X-ray emission from the short-period eclipsing binary XY UMa", Monthly Notices of the Royal Astronomical Society, 243: 557–564, Bibcode:1990MNRAS.243..557B.
  • Arevalo, M. J.; Lazaro, C. (March 1990), "Infrared Photometry of the RS CVn Short-Period Systems XY UMa and WY CNC", Astronomical Journal, 99: 983, Bibcode:1990AJ.....99..983A, doi:10.1086/115389.
  • Banks, T.; Budding, E. (March 1989), "Light Curves for XY UMa", Information Bulletin on Variable Stars, 3304 (1): 1, Bibcode:1989IBVS.3304....1B.
  • Heckert, P.; et al. (October 1988), "1987 Photometry of XY Ursae Majoris", Information Bulletin on Variable Stars, 3253 (1): 1, Bibcode:1988IBVS.3253....1H.
  • Zeilik, M.; et al. (June 1988), "1988 BVRI Photometry of XY UMa", Information Bulletin on Variable Stars, 3200 (1): 1, Bibcode:1988IBVS.3200....1Z.
  • Jassur, D. M. Z. (December 1986), "Photometric Observations and Interpretation of the Eclipsing Binary System Xy-Ursae", Astrophysics and Space Science, 128 (2): 369–375, Bibcode:1986Ap&SS.128..369J, doi:10.1007/BF00644585, S2CID 121784675.
  • Bedford, D. K.; et al. (October 1986), "The X-Ray Light Curve of XY Ursae Maioris", Information Bulletin on Variable Stars, 2946 (1): 1, Bibcode:1986IBVS.2946....1B.
  • Bedford, D. K.; Geyer, E. H. (1986), "Simultaneous Optical- and EXOSAT-Observations of the Spot Active Eclipsing Binary XY UMa", Mitteilungen der Astronomischen Gesellschaft, 67: 305, Bibcode:1986MitAG..67..305B.
  • Zeilik, M.; et al. (April 1983), "The short-period eclipsing system XY UMa : 1982 UBV light curves and a flare-like event", Astronomical Journal, 88: 532–534, Bibcode:1983AJ.....88..532Z, doi:10.1086/113339.
  • Zeilik, M.; et al. (September 1982), "An Intense Optical Flare from XY UMa", Information Bulletin on Variable Stars, 2200 (1): 1, Bibcode:1982IBVS.2200....1Z.
  • Zeilik, M.; et al. (June 1982), "1982 UBVR Photometric Observations of XY UMa", Information Bulletin on Variable Stars, 2169: 1, Bibcode:1982IBVS.2169....1Z.
  • Geyer, E. H.; Metz, K. (December 1977), "A Polarimetric Investigation of the Eclipsing Binary XY Ursae Majoris", Astrophysics and Space Science, 52 (2): 351–356, Bibcode:1977Ap&SS..52..351G, doi:10.1007/BF01093871, S2CID 121665339.
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