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]

Related Research Articles

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

W Ursae Majoris is the variable star designation for a binary star system in the northern constellation of Ursa Major. It has an apparent visual magnitude of about 7.9, which is too faint to be seen with the naked eye. However, it can be viewed with a small telescope. Parallax measurements place it at a distance of roughly 169 light years (52 parsecs) from Earth.

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

Omega Ursae Majoris is the Bayer designation for a binary star system in the northern circumpolar constellation of Ursa Major. It is visible to the naked eye with an apparent visual magnitude of 4.61. Based upon an annual parallax shift of 13.24 mas, it is roughly 246 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.11 due to interstellar dust.

<span class="mw-page-title-main">AB Andromedae</span> Binary star in the Andromeda constellation

AB Andromedae is a binary star in the constellation Andromeda. Paul Guthnick and Richard Prager discovered that the star is an eclipsing binary in 1927. Its maximum apparent visual magnitude is 9.49 but shows a variation in brightness down to a magnitude of 10.46 in a periodic cycle of roughly 8 hours. The observed variability is typical of W Ursae Majoris variable stars, so the two stars in this system form a contact binary.

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

V752 Centauri is multiple star system and variable star in the constellation of Centaurus. An eclipsing binary, its apparent magnitude has a maximum of 9.10, dimming to 9.66 during primary eclipse and 9.61 during secondary eclipse. Its variability was discovered by Howard Bond in 1970. From parallax measurements by the Gaia spacecraft, the system is located at a distance of 410 light-years from Earth.

<span class="mw-page-title-main">VW Leonis Minoris</span> Star system in the constellation Leo Minor

VW Leo Minoris is a tight quadruple star system, located in the constellation of Leo Minor. With a peak combined apparent visual magnitude of 8.07, it is too faint to be seen with the naked eye. Parallax measurements give a distance estimate of approximately 370 light years from the Sun, and it is drifting further away with a radial velocity of +5 km/s.

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

TU Ursae Majoris is a variable star in the northern circumpolar constellation of Ursa Major. It is classified as a Bailey-type 'ab' RR Lyrae variable with a period of 0.557648 days that ranges in brightness from apparent visual magnitude of 9.26 down to 10.24. The distance to this star is approximately 2,090 light years based on parallax measurements. It is located near the north galactic pole at a distance that indicates this is a member of the galactic halo.

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

TX Ursae Majoris is an eclipsing binary star system in the northern circumpolar constellation of Ursa Major. With a combined apparent visual magnitude of 6.97, the system is too faint to be readily viewed with the naked eye. The pair orbit each other with a period of 3.063 days in a circular orbit, with their orbital plane aligned close to the line of sight from the Earth. During the primary eclipse, the net brightness decreases by 1.74 magnitudes, while the secondary eclipse results in a drop of just 0.07 magnitude. TX UMa is located at a distance of approximately 780 light years from the Sun based on parallax measurements, but is drifting closer with a mean radial velocity of −13 km/s.

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

UX Ursae Majoris is an Algol type binary star system in the northern circumpolar constellation of Ursa Major. It is classified as a nova-like variable star similar to DQ Herculis, although no eruptions have been reported. Since its discovery in 1933, this system has been the subject of numerous studies attempting to determine its properties. The combined apparent visual magnitude of UX UMa ranges from 12.57 down to 14.15. The system is located at a distance of approximately 952 light years from the Sun based on parallax, and is drifting further away with a radial velocity of 112 km/s.

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

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

<span class="mw-page-title-main">BZ Ursae Majoris</span> Dwarf Nova in the constellation Ursa Major

BZ Ursae Majoris is a dwarf nova star system in the northern circumpolar constellation of Ursa Major. It consists of a white dwarf primary in a close orbit with a red dwarf. The latter star is donating mass, which is accumulating in an accretion disk orbiting the white dwarf. The system is located at a distance of approximately 505 light years from the Sun based on parallax measurements.

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

EQ Tauri is a triple star system in the equatorial constellation of Taurus that includes a contact eclipsing binary. The system is too faint to be viewed with the naked eye, having a baseline apparent visual magnitude of 10.5. During the primary eclipse, the brightness of the system drops to magnitude 11.03, then to 10.97 during the secondary minimum. The secondary eclipse is total. Based on parallax measurements, it is located at a distance of approximately 730 light years from the Sun.

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

AG Virginis is an eclipsing binary star system in the equatorial constellation of Virgo. With a maximum apparent visual magnitude of 8.51 it is too faint to be visible to the naked eye. The system is located at a distance of approximately 820 light years from the Sun based on parallax measurements.

<span class="mw-page-title-main">UV Piscium</span> Binary star system in the Pisces constellation

UV Piscium is a binary star system in the constellation of Pisces. With a peak apparent visual magnitude of 8.98, it is too faint to be visible to the naked eye. This is an eclipsing binary system that decreases to magnitude 10.05 during the primary eclipse, then to magnitude 9.54 with the secondary eclipse. It is located at a distance of 232 light years from the Sun based on parallax measurements, and is receding with a radial velocity of 6.5 km/s. The position of this star near the ecliptic means it is subject to lunar occultation.

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

VZ Piscium is a binary star system in the equatorial constellation of Pisces. it is located at a distance of 178 light years from the Sun based on parallax measurements, and has an apparent visual magnitude of about 10.3. This is an eclipsing binary system that undergoes shallow eclipses; the brightness decreases to magnitude 10.45 during the primary eclipse, then to magnitude 10.43 with the secondary eclipse, although as a contact binary the brightness varies continuously with no period of constant maximum brightness. The system is drifting closer with a radial velocity of approximately −4 km/s, and has a net heliocentric velocity of 144.1 km/s.

<span class="mw-page-title-main">ER Vulpeculae</span> Variable star in the constellation Vulpecula

ER Vulpeculae is a binary star system in the northern constellation of Vulpecula, abbreviated ER Vul. It is a variable star system with a brightness that ranges from an apparent visual magnitude of 7.27 down to 7.49, which is too faint to be visible to the naked eye. This system is located at a distance of 165 light years from the Sun based on parallax measurements. It is drifting closer with a radial velocity of −25 km/s.

<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

VV Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated VV UMa. It is a variable star system with a brightness that cycles around an apparent visual magnitude of 10.19, making it too faint to be visible to the naked eye. The system is located at a distance of approximately 1,500 light years based on parallax measurements.

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

BE Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated BE UMa. The two components are an unusual M-class dwarf star and a subdwarf O star, borderline white dwarf. It is classified as a detached Algol variable and ranges in brightness from an apparent visual magnitude of 14.8 down to 17.8. This is too faint to be visible to the naked eye. The distance to this system is approximately 4,600 light years based on parallax measurements.

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

DM Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated DM UMa. It is sometimes identified by the Bonner Durchmusterung catalogue designation BD +61 1211; DM UMa is the variable star designation. The system has a combined apparent visual magnitude of 9.29, which is too faint to be visible to the naked eye. Based on parallax measurements, the system is located at a distance of approximately 606 light years from the Sun, but it is drifting closer with a heliocentric radial velocity of −7 km/s.

<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.

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) (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics . arXiv: 2208.00211 . doi: 10.1051/0004-6361/202243940 . Gaia DR3 record for this source at VizieR.

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