AW Ursae Majoris

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AW Ursae Majoris
AWUMaLightCurve.png
A light curve for AW Ursae Majoris, plotted from TESS data [1]
Observation data
Epoch J2000       Equinox J2000
Constellation Ursa Major
Right ascension 11h 30m 04.316s [2]
Declination +29° 57′ 52.67″ [2]
Apparent magnitude  (V)Max: 6.83
Min1: 7.13
Min2: 7.08 [3]
Characteristics
Spectral type F0V–F1V [4]
Variable type Contact W UMa [3]
Astrometry
Radial velocity (Rv)−17.0±1.57 [5]  km/s
Proper motion (μ)RA: −84.298  mas/yr [2]
Dec.: −198.900  mas/yr [2]
Parallax (π)14.7836 ± 0.0295  mas [2]
Distance 220.6 ± 0.4  ly
(67.6 ± 0.1  pc)
Absolute magnitude  (MV)2.74±0.12 [4]
Orbit [6]
Period (P)0.438732 d
Semi-major axis (a)2.74 ± 0.93 Gm (0.0183 ± 0.0062 AU)
Eccentricity (e)0.00 (assumed)
Inclination (i)78.3 [7] °
Periastron epoch (T)2,443,974.198  JD
Argument of periastron (ω)
(secondary)		0.00°
Semi-amplitude (K1)
(primary)		29±8 km/s
Semi-amplitude (K2)
(secondary)		423±80 km/s
Details
Primary
Mass 1.79±0.14 [8]   M☉
Radius 1.49 [9]   R☉
Luminosity 5.9 –6.5 [4]   L☉
Temperature 6.980 [4]   K
Metallicity [Fe/H]−0.01±0.08 [9]   dex
Rotational velocity (v sin i)181.4 [9]  km/s
Age 3.26±0.17 [8]   Gyr
Secondary
Mass 0.14±0.01 [8]   M☉
Radius ≤ 0.678 [10]   R☉
Luminosity0.57 –0.73 [4]   L☉
Temperature 6,201 –6,901 [4]   K
Other designations
Paczynski’s star [9] , AW UMa, BD+30°2163, FK5  2916, GC  15772, HD  99946, HIP  56109, SAO  62579, PPM  101203, WDS J11301+2958A, LTT  13131 [11]
Database references
SIMBAD data

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 [7] (W UMa) 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. [3] 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. [5] The system has a high proper motion, traversing the celestial sphere at the rate of 0.216  arc second per annum. [12]

While observing the variable star TU UMa in 1964, B. Paczyński noted that the comparison star BD +30°2163 was itself variable. The latter was determined to be a W UMa-type eclipsing binary with a period of 0.438727 days. A flat light curve during the minimum suggested the primary eclipse is full or annular. [13] In 1972, S. W. Mochnacki and N. A. Doughty modelled the system and determined a very low mass ratio of 0.079±0.08 for the pair, indicating that the secondary has 8% of the mass of the primary. [14]

E. J. Woodward and associates in 1980 found evidence of a recent period change for the system and suspected an intrinsic variability based on mismatches in the light curves over time. [15] In 1981, B. J. McLean made radial velocity measurements of the system and used them to compute orbital elements. [6] R. K. Srivastava confirmed period changes in the range of 10−6 to 10−7 days occurred during the interval from 1963 to 1988. [16] Further period changes were noted in 1997. [17] In 1999, T. Pribulla and associates proposed that observed velocity changes to the system are the result of an undetected third component. This would have 0.85±0.13 times the mass of the Sun and an orbital period of 398 days. Period changes to the binary are attributed to mass transfer. [7]

B. Paczyński and associates in 2007 proposed an evolutionary model for the system. They suggested that the current secondary was the original primary for the system, and as a result was the first to evolve off the main sequence and expand. Most of the star's mass was then transferred to the companion, until the system reached the current mass ratio. This left the current secondary with a helium core and much of its outer hydrogen envelope stripped away. Because of the mass acquisition, the present day primary now resembles a zero age main sequence star. [10] In 2008, T. Pribulla and S. M. Rucinski called into question the assumption that this is a contact binary system, suggesting instead that the pair share a luminous equatorial belt. [4]

O. J. Eggen in 1967 noted that a nearby star is a common proper motion companion to AW UMa, [18] which may form a tertiary component to this system. This magnitude 9.41 star is located at an angular separation of 67.2″ from the binary pair. [19] The star has a parallax of 14.7  mas , indicating a distance of 222 light years, and is modelled to be a middle-aged main sequence star similar to the Sun. [20]

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<span class="mw-page-title-main">65 Ursae Majoris</span> Star system in the constellation Ursa Major

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<span class="mw-page-title-main">V752 Centauri</span> Star in the constellation Centaurus

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<span class="mw-page-title-main">TU Ursae Majoris</span>

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

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<span class="mw-page-title-main">XY Ursae Majoris</span> Eclipsing binary star system in the constellation of Ursa Major

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

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<span class="mw-page-title-main">AG Virginis</span> Eclipsing binary star in the constellation Virgo

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<span class="mw-page-title-main">VZ Piscium</span> Variable star in the constellation Pisces

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<span class="mw-page-title-main">AH Virginis</span> Star in the constellation Virgo

AH Virginis is a contact binary star system in the equatorial constellation of Virgo, abbreviated AH Vir. It is a variable star with a brightness that peaks at an apparent visual magnitude of 9.18, making it too faint to be viewed with the naked eye. The distance to this system is approximately 338 light years based on parallax measurements, and it is drifting further away with a mean radial velocity of 7 km/s. O. J. Eggen in 1969 included this system as a probable member of the Wolf 630 group of co-moving stars.

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

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

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<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.

U Pegasi is a binary star system in the constellation of Pegasus, abbreviated U Peg. The pair form an eclipsing binary with a combined peak apparent visual magnitude of 9.23, which is far too faint to be visible to the naked eye. During the primary eclipse the magnitude decreases to 10.07, while the secondary eclipse only drops to magnitude 9.73. This system is located at a distance of approximately 596 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of around −28.5 km/s.

References

  1. ↑ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, retrieved 30 September 2022.
  2. 1 2 3 4 5 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 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. 1 2 3 4 5 6 7 Pribulla, T.; Rucinski, S. M. (May 2008), "Radial velocity mapping of Paczyński's star AW UMa: not a contact binary", Monthly Notices of the Royal Astronomical Society, 386 (1): 377–389, arXiv: 0801.4537 , Bibcode:2008MNRAS.386..377P, doi: 10.1111/j.1365-2966.2008.13033.x , S2CID   14910861.
  5. 1 2 Bilir, S.; et al. (February 2005), "Kinematics of W Ursae Majoris type binaries and evidence of the two types of formation", Monthly Notices of the Royal Astronomical Society , 357 (2): 497–517, arXiv: astro-ph/0411291 , Bibcode:2005MNRAS.357..497B, doi: 10.1111/j.1365-2966.2005.08609.x , S2CID   16274339.
  6. 1 2 McLean, B. J. (June 1981), "Radial velocities for contact binary systems. I. W UMa and AW UMa", Monthly Notices of the Royal Astronomical Society, 195: 931–938, Bibcode:1981MNRAS.195..931M, doi: 10.1093/mnras/195.4.931 .
  7. 1 2 3 Pribulla, T.; et al. (May 1999), "The contact binary AW Ursae Majoris as a member of a multiple system", Astronomy and Astrophysics, 345: 137–148, Bibcode:1999A&A...345..137P.
  8. 1 2 3 Yıldız, M. (January 2014), "Origin of W UMa-type contact binaries - age and orbital evolution", Monthly Notices of the Royal Astronomical Society, 437 (1): 185–194, arXiv: 1310.5526 , Bibcode:2014MNRAS.437..185Y, doi: 10.1093/mnras/stt1874 .
  9. 1 2 3 4 Rucinski, Slavek M. (February 2015), "Time Sequence Spectroscopy of AW UMa. The 518 nm Mg i Triplet Region Analyzed With Broadening Functions", The Astronomical Journal, 149 (2): 14, arXiv: 1409.0686 , Bibcode:2015AJ....149...49R, doi:10.1088/0004-6256/149/2/49, S2CID   119243218, 49.
  10. 1 2 Paczyński, B.; et al. (July 2007), "A model of AW UMa", Monthly Notices of the Royal Astronomical Society, 378 (3): 961–965, arXiv: astro-ph/0612600 , Bibcode:2007MNRAS.378..961P, doi: 10.1111/j.1365-2966.2007.11822.x , S2CID   14251578.
  11. ↑ "AW UMa". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2022-09-21.
  12. ↑ 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.
  13. ↑ Paczynski, B. (February 1964), "BD +30 2163, a new W UMa variable", Astronomical Journal, 69: 124–130, Bibcode:1964AJ.....69..124P, doi:10.1086/109240.
  14. ↑ Mochnacki, S. W.; Doughty, N. A. (1972), "A model for the totally eclipsing W Ursae Majoris system AW UMa", Monthly Notices of the Royal Astronomical Society, 156: 51, Bibcode:1972MNRAS.156...51M, doi: 10.1093/mnras/156.1.51 .
  15. ↑ Woodward, E. J.; et al. (January 1980), "Analyses of new light curve of AW Ursae Majoris", Astronomical Journal, 85: 50–54, Bibcode:1980AJ.....85...50W, doi:10.1086/112635.
  16. ↑ Srivastava, R. K. (April 1989), "Period Study of AW-Ursae", Astrophysics and Space Science, 154 (2): 179–187, Bibcode:1989Ap&SS.154..179S, doi:10.1007/BF00642802, S2CID   119665409.
  17. ↑ Pribulla, T.; Chochol, D.; Rovithis, P.; Rovithis-Livaniou, H. (February 1997), "Sudden Period Change in the Contact Binary AW UMa?", Information Bulletin on Variable Stars, 4435: 1, Bibcode:1997IBVS.4435....1P.
  18. ↑ Eggen, O. J. (1967), "Contact binaries, II", Memoirs of the Royal Astronomical Society, 70: 111, Bibcode:1967MmRAS..70..111E. See the entry for BD +30°2163.
  19. ↑ Lépine, Sébastien; Bongiorno, Bethany (March 2007), "New Distant Companions to Known Nearby Stars. II. Faint Companions of Hipparcos Stars and the Frequency of Wide Binary Systems", The Astronomical Journal, 133 (3): 889–905, arXiv: astro-ph/0610605 , Bibcode:2007AJ....133..889L, doi:10.1086/510333, S2CID   16800796.
  20. ↑ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.

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