Astronomy:XY Ursae Majoris

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Short description: Eclipsing binary star system in the constellation of Ursa Major
XY Ursae Majoris
XYUMaLightCurve.png
A light curve for XY Ursae Majoris, plotted from TESS data[1]
Observation data
Equinox J2000.0]] (ICRS)
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[2] mas/yr
Dec.: −182.641[2] mas/yr
Parallax (π)14.7223 ± 0.0137[2] mas
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, 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. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html. 
  2. 2.0 2.1 2.2 2.3 2.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  3. 3.0 3.1 3.2 3.3 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  4. 4.0 4.1 4.2 4.3 4.4 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, doi:10.1111/j.1365-2966.2001.04712.x, Bibcode2001MNRAS.326.1489L. 
  5. 5.0 5.1 Samus', N. N et al. (2017), "General catalogue of variable stars", Astronomy Reports, GCVS 5.1 61 (1): 80, doi:10.1134/S1063772917010085, Bibcode2017ARep...61...80S. 
  6. 6.0 6.1 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, doi:10.1111/j.1365-2966.2004.07588.x, Bibcode2004MNRAS.349.1069K. 
  7. 7.0 7.1 Pribulla, Theodor et al. (May 2007), "Radial Velocity Studies of Close Binary Stars. XII", The Astronomical Journal 133 (5): 1977–1987, doi:10.1086/512772, Bibcode2007AJ....133.1977P. 
  8. 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 Yuan, Jinzhao (May 2010), "Period Variation and Asymmetry Light Curves of XY Ursae Majoris", The Astronomical Journal 139 (5): 1801–1807, doi:10.1088/0004-6256/139/5/1801, Bibcode2010AJ....139.1801Y. 
  9. "XY UMa". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=XY+UMa. 
  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, doi:10.1086/427854, Bibcode2005AJ....129.1483L. 
  11. 11.0 11.1 Geyer, E. H. (1976), Eggleton, P.; Mitton, S.; Whelan, J., 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.) 73 (73): p. 313, Bibcode1976IAUS...73..313G. Symposium sponsored by the International Astronomical Union. 
  12. Lorenzi, L.; Scaltriti, F. (1977), "The variable light-curve of the eclipsing binary XY UMa", Acta Astronomica 27: 273–279, Bibcode1977AcA....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, doi:10.1007/BF00643045, Bibcode1977Ap&SS..48..137G. 
  14. Pojmanski, G.; Geyer, E. H. (1990), "The period behaviour of the spotted binary XY UMa", Acta Astronomica 40: 245, Bibcode1990AcA....40..245P. 
  15. Pribulla, T. et al. (June 2001), "An active binary XY UMa revisited", Astronomy and Astrophysics 371 (3): 997–1011, doi:10.1051/0004-6361:20010459, Bibcode2001A&A...371..997P. 
  16. 16.0 16.1 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, doi:10.1088/1674-4527/16/8/131, 131, Bibcode2016RAA....16..131G. 

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, doi:10.1086/323091, Bibcode2001AJ....122.1965S. 
  • Yeates, C. M. et al. (August 2000), "Times of Minimum Light for XY Ursae Majoris", Information Bulletin on Variable Stars 4943 (1): 1, Bibcode2000IBVS.4943....1Y. 
  • Kjurkchieva, D. et al. (February 2000), "Multicolour high-speed photometry and Hα spectroscopy of XY UMa", Astronomy and Astrophysics 354: 909–914, Bibcode2000A&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, doi:10.1086/300952, Bibcode1999AJ....118.1015A. 
  • 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, Bibcode1998A&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, Bibcode1998AcA....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, doi:10.1046/j.1365-8711.1998.01272.x, Bibcode1998MNRAS.295..825J. 
  • 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, doi:10.1051/aas:1998348, Bibcode1998A&AS..127..257E. 
  • Pojmanski, G.; Udalski, A. (October 1997), "An Orbital Solution for RS CVn Binary Star XY UMa", Acta Astronomica 47: 451–466, Bibcode1997AcA....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, doi:10.1093/mnras/287.3.567, Bibcode1997MNRAS.287..567C. 
  • 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, Bibcode1995IBVS.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, doi:10.1093/mnras/267.4.1081, Bibcode1994MNRAS.267.1081H. 
  • 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, doi:10.1093/mnras/248.1.168, Bibcode1991MNRAS.248..168R. 
  • Geyer, E. H. (1991), "On the long term variability of the chromospheric active close binary XY Ursae Majoris", Astronomische Gesellschaft Abstract Series 6: 79, Bibcode1991AGAb....6...79G. 
  • Zeilik, M. et al. (October 1990), "1990 BVR Photometry of XY UMa", Information Bulletin on Variable Stars 3535 (1): 1, Bibcode1990IBVS.3535....1Z. 
  • Arévalo, M. J.; Lázaro, C. (July 1990), "Infrared Photometry of XY-Ursae", Astrophysics and Space Science 169 (1–2): 247–249, doi:10.1007/BF00640725, Bibcode1990Ap&SS.169..247A. 
  • 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, Bibcode1990MNRAS.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, doi:10.1086/115389, Bibcode1990AJ.....99..983A. 
  • Banks, T.; Budding, E. (March 1989), "Light Curves for XY UMa", Information Bulletin on Variable Stars 3304 (1): 1, Bibcode1989IBVS.3304....1B. 
  • Heckert, P. et al. (October 1988), "1987 Photometry of XY Ursae Majoris", Information Bulletin on Variable Stars 3253 (1): 1, Bibcode1988IBVS.3253....1H. 
  • Zeilik, M. et al. (June 1988), "1988 BVRI Photometry of XY UMa", Information Bulletin on Variable Stars 3200 (1): 1, Bibcode1988IBVS.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, doi:10.1007/BF00644585, Bibcode1986Ap&SS.128..369J. 
  • Bedford, D. K. et al. (October 1986), "The X-Ray Light Curve of XY Ursae Maioris", Information Bulletin on Variable Stars 2946 (1): 1, Bibcode1986IBVS.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, Bibcode1986MitAG..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, doi:10.1086/113339, Bibcode1983AJ.....88..532Z. 
  • Zeilik, M. et al. (September 1982), "An Intense Optical Flare from XY UMa", Information Bulletin on Variable Stars 2200 (1): 1, Bibcode1982IBVS.2200....1Z. 
  • Zeilik, M. et al. (June 1982), "1982 UBVR Photometric Observations of XY UMa", Information Bulletin on Variable Stars 2169: 1, Bibcode1982IBVS.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, doi:10.1007/BF01093871, Bibcode1977Ap&SS..52..351G.