W Ursae Minoris

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W Ursae Minoris
WUMiLightCurve.png
A visual band light curve for W Ursae Minoris, adapted from Devinney et al. (1970) [1]
Observation data
Epoch J2000       Equinox J2000
Constellation Ursa Minor
Right ascension 16h 08m 27.2728s [2]
Declination +86° 11 59.5511 [2]
Apparent magnitude  (V)8.51-9.59 [3]
Characteristics
Spectral type A1/2V [4] (A3V + G2IV) [5]
Variable type Algol [3]
Astrometry
Radial velocity (Rv)−15.3±1.1 [6]  km/s
Proper motion (μ)RA: −12.128±0.057 [2]   mas/yr
Dec.: 15.934±0.058 [2]   mas/yr
Parallax (π)2.4144 ± 0.0315  mas [2]
Distance 1,350 ± 20  ly
(414 ± 5  pc)
Orbit [6]
Period (P)1.7 days
Semi-major axis (a)10.01±0.06  R
Eccentricity (e)0
Inclination (i)83.57±0.18°
Semi-amplitude (K1)
(primary)
90.4±1.5 km/s
Semi-amplitude (K2)
(secondary)
196.6±2.6 km/s
Details [6]
Aa
Mass 3.22±0.08  M
Radius 9.63±0.04  R
Luminosity 89±6  L
Surface gravity (log g)3.83±0.02  cgs
Temperature 9,310±90  K
Ab
Mass 1.44±0.05  M
Radius 3.09±0.03  R
Luminosity6.5+1.3
−1.1
  L
Surface gravity (log g)3.62±0.02  cgs
Temperature 5,240±200  K
Age ≈400  Myr
Other designations
HD  150265, HIP  79069, SAO  2692 [7]
Database references
SIMBAD data

W Ursae Minoris is an eclipsing binary star system in the constellation Ursa Minor. Its apparent magnitude ranges from 8.51 to 9.59 over 1.7 days as one star passes in front of the other relative to observers on Earth. [3] The combined spectrum of the system is A1/2V.

Slight changes in the orbital period suggest that there is a third component of the multiple star system, most likely a red dwarf, with an orbital period of 62.2±3.9 years. [8] Another study suggests that the third star has a minimum mass of 0.49 M and an orbit of about 72 years. [6]

The two main stars are currently thought to have masses of 3.2  M and 1.4 M respectively. Models of their evolution and mass transfer suggest that the secondary star was initially the more massive of the two and that it has lost mass to what is now the primary as well as losing mass completely from the system. The two stars have also spiralled in towards each other over the few hundred million years since they formed. [6]

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">Epsilon Ursae Minoris</span> Binary star system in the constellation Ursa Minor

Epsilon Ursae Minoris is a binary star system in the northern circumpolar constellation of Ursa Minor. It is visible to the naked eye with a combined apparent visual magnitude of 4.19. Based upon an annual parallax shift of 10.73 mas as seen from the Earth, it is located around 300 light years from the Sun. The pair are drawing nearer to the Sun with a radial velocity of −10.57 km/s.

<span class="mw-page-title-main">AR Aurigae</span> Binary star system in the constellation Auriga

AR Aurigae, also known by its Flamsteed designation 17 Aurigae, is a binary star in the constellation Auriga. Based on parallax measurements made by the Hipparcos spacecraft, it is approximately 461 light-years from Earth.

<span class="mw-page-title-main">S Antliae</span> Star in the constellation Antlia

S Antliae is a W Ursae Majoris-type eclipsing binary star in Antlia.

11 Ursae Minoris is a single star located approximately 410 light years away in the northern circumpolar constellation of Ursa Minor. The star is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 5.15. It is moving closer to the Earth with a heliocentric radial velocity of −17.5 km/s.

<span class="mw-page-title-main">Y Sextantis</span> Variable star in the constellation Sextans

Y Sextantis, abbreviated as Y Sex, is a variable star system in the equatorial constellation of Sextans. The system is invisible to the naked eye with a mean apparent visual magnitude of 9.88. It is located roughly at 1,300 light years from the Sun based on parallax.

<span class="mw-page-title-main">RR Ursae Minoris</span> Star in the constellation Ursa Minor

RR Ursae Minoris, abbreviated RR UMi, is a binary star system in the northern circumpolar constellation of Ursa Minor. It can be viewed with the naked eye, typically having an apparent visual magnitude of around 4.710. Based upon an annual parallax shift of 10.0 mas as seen from Earth's orbit, it is located 330 light years away. The system is moving further from the Sun with a heliocentric radial velocity of +6 km/s.

<span class="mw-page-title-main">RW Ursae Minoris</span> Nova that appeared in 1956

RW Ursae Minoris is a cataclysmic variable star system that flared up as a nova in the constellation Ursa Minor in 1956.

<span class="mw-page-title-main">RU Ursae Minoris</span> Star in the constellation Ursa Minor

RU Ursae Minoris is a binary star system in the constellation Ursa Minor. Its apparent magnitude ranges from 10 to 10.66 over 0.52 days as one star passes in front of the other relative to observers on Earth. Its component stars were calculated to be a primary star of spectral type F0IV/V and a secondary of spectral type K5V, both slightly more luminous than their spectral types indicate. The system is semidetached, as the secondary star is filling its Roche lobe and transferring matter to the primary. The primary is between 2.2 and 2.3 times as massive as the Sun, with 1.8 times its radius and around 8 times its luminosity. The secondary has around 0.72 times the Sun's mass, 1.1 times its radius and between 0.58 and 0.86 times its luminosity.

<span class="mw-page-title-main">TW Andromedae</span> Star in the constellation Andromeda

TW Andromedae is an eclipsing binary star, classified also as an Algol variable star, in the constellation Andromeda. Its brightness varies with a period of 4.12 days, and has a typical brightness of magnitude 8.98 but decreasing down to a magnitude of 11.04 during the main eclipse.

<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">AE Phoenicis</span> Star in the constellation Phoenix

AE Phoenicis is a variable star in the constellation of Phoenix. An eclipsing binary, its apparent magnitude has a maximum of 7.56, dimming to 8.25 during primary eclipse and 8.19 during secondary eclipse. From parallax measurements by the Gaia spacecraft, the system is located at a distance of 168 light-years from Earth.

<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">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">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">RW Tauri</span> Eclipsing binary star in the constellation Taurus

RW Tauri is a binary star system in the equatorial constellation of Taurus. It has the designation HD 25487 in the Henry Draper Catalogue, while RW Tauri is the variable star designation. With a peak apparent visual magnitude of 8.05, it is too faint to be visible to the naked eye. The distance to this system is approximately 940 light years based on parallax measurements.

<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">AW Ursae Majoris</span> Variable star in the constellation Ursa Major

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 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. 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. The system has a high proper motion, traversing the celestial sphere at the rate of 0.216 arc second per annum.

<span class="mw-page-title-main">RS Sagittarii</span> Eclipsing binary star system in the constellation Sagittarius

RS Sagittarii is an eclipsing binary star system in the southern constellation of Sagittarius, abbreviated RS Sgr. It is a double-lined spectroscopic binary with an orbital period of 2.416 days, indicating that the components are too close to each other to be individually resolved. The system has a combined apparent visual magnitude of 6.01, which is bright enough to be faintly visible to the naked eye. During the primary eclipse the brightness drops to magnitude 6.97, while the secondary eclipse is of magnitude 6.28. The distance to this system is approximately 1,420 light years based on parallax measurements.

<span class="mw-page-title-main">RT Persei</span> Star system in the constellation Perseus

RT Persei is a variable star system in the northern constellation of Perseus, abbreviated RT Per. It is an eclipsing binary system with an orbital period of 0.84940032 d (20.386 h). At peak brightness the system has an apparent visual magnitude of 10.46, which is too faint to be viewed with the naked eye. During the eclipse of the primary this decreases to magnitude 11.74, then to magnitude 10.67 with the secondary eclipse. The distance to this system is approximately 628 light years based on parallax measurements. It is drifting closer with a heliocentric radial velocity of about −12 km/s.

References

  1. Devinney, Edward J.; Hall, Douglas S.; Ward, David H. (February 1970). "Two Independent Photoelectric Light Curves and Solutions of W Ursae Minoris". Publications of the Astronomical Society of the Pacific. 82 (484): 10. Bibcode:1970PASP...82...10D. doi: 10.1086/128884 . S2CID   121750637.
  2. 1 2 3 4 5 Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv: 1804.09365 . Bibcode: 2018A&A...616A...1G . doi: 10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR.
  3. 1 2 3 Watson, Christopher (4 January 2010). "W Ursae Minoris". AAVSO Website. American Association of Variable Star Observers . Retrieved 18 July 2015.
  4. Hill, G.; et al. (1975). "MK Classifications of some Northern Hemisphere Binary Systems". Memoirs of the Royal Astronomical Society. 79: 131. Bibcode:1975MmRAS..79..131H.
  5. Malkov, Oleg Yu (February 2020). "Semidetached double-lined eclipsing binaries: Stellar parameters and rare classes". Monthly Notices of the Royal Astronomical Society. 491 (4): 5489–5497. Bibcode:2020MNRAS.491.5489M. doi: 10.1093/mnras/stz3363 .
  6. 1 2 3 4 5 Soydugan, Faruk; Soydugan, Esin; Aliçavuş, Fahri (2020). "Investigation of near-contact semi-detached binary WUMi through observations and evolutionary models". Research in Astronomy and Astrophysics. 20 (4): 052. arXiv: 1912.03664 . Bibcode:2020RAA....20...52S. doi:10.1088/1674-4527/20/4/52. S2CID   208920968.
  7. "W UMi". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-10-07.
  8. Kreiner, J. M.; Pribulla, T.; Tremko, J.; Stachowski, G. S.; Zakrzewski, B. (2008). "Period analysis of three close binary systems: TW And, TT Her and W UMi". Monthly Notices of the Royal Astronomical Society. 383 (4): 1506–12. Bibcode:2008MNRAS.383.1506K. doi: 10.1111/j.1365-2966.2007.12652.x .