V1191 Cygni

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V1191 Cygni
V1191CygLightCurve.png
A visual band light curve for V1191 Cygni, adapted from Ostadnezhad et al. (2014) [1]
Observation data
Epoch J2000       Equinox J2000
Constellation Cygnus
Right ascension 20h 16m 50.8045s [2]
Declination +41° 57′ 41.360″ [2]
Apparent magnitude  (V)10.99 [3]
Characteristics
Spectral type F6V + G5V [4]
Apparent magnitude  (B)11.41 [3]
Apparent magnitude  (R)10.55 [5]
Apparent magnitude  (I)10.06 [6]
Apparent magnitude  (J)9.82 [7]
Apparent magnitude  (H)9.56 [7]
Apparent magnitude  (K)9.51 [7]
B−V color index 0.62 [8]
Variable type W UMa [9]
Astrometry
A
Proper motion (μ)RA: 38.4 ± 1.7 [3]   mas/yr
Dec.: 25.1 ± 1.6 [3]   mas/yr
Distance 278 ± 31 [10]   pc
Absolute magnitude  (MV)3.82 [10]
B
Absolute magnitude  (MV)5.73 [10]
Orbit
Period (P)0.3134 d [11]
Semi-major axis (a)2.182 R☉ [12]
Details
A
Mass 1.29 ± 0.08 [10]   M☉
Radius 1.31 ± 0.18 [10]   R☉
Luminosity (bolometric)2.71 ± 0.44 [10]   L☉
Surface gravity (log g)4.31 [10]   cgs
Temperature 6500 [10]   K
Age 3.85 ± 0.21 [12]   Gyr
B
Mass 0.13 ± 0.01 [10]   M☉
Radius 0.52 ± 0.15 [10]   R☉
Luminosity (bolometric)0.46 ± 0.08 [10]   L☉
Surface gravity (log g)4.12 [10]   cgs
Temperature 6610 ± 200 [10]   K
Age 3.85 ± 0.21 [12]   Gyr
Other designations
GSC 03159-01512, 2MASS J20165081+4157413, SBC9 2996, TYC 3159-1512-1
Database references
SIMBAD data

V1191 Cygni is the variable star designation for an overcontact binary star system in the constellation Cygnus. [13] First found to be variable in 1965, it is a W Ursae Majoris variable with a maximum apparent magnitude 10.82. It drops by 0.33 magnitudes during primary eclipses with a period of 0.3134 days, while dropping by 0.29 magnitudes during secondary eclipses. [11] The primary star, which is also the cooler star, appears to have a spectral type of F6V, while the secondary is slightly cooler with a spectral type of G5V. [4] With a mass of 1.29 solar masses and a luminosity of 2.71 solar luminosities, it is slightly more massive and luminous than the sun, while the secondary is only around 1/10 as massive and less than half as luminous. With a separation of 2.20 solar radii, the mass transfer of about 2×10−7 solar masses per year from the secondary to the primary is one of the highest known for a system of its type. [10]

V1191 Cygni is a W-type W UMa variable, [8] meaning that the primary eclipse occurs when the less-massive component is eclipsed by the larger, more massive component, although the masses are unusually different for such a system. [14] The current period is very short for a system of its spectral type, suggesting that the stars are relatively small for their mass and age, [14] which is likely around 3.85 billion years. [12] The pair's orbital period is increasing at a rate of over 4×10−7 days per year, one of the fastest known rates among contact binary systems, [8] likely due to the high rate of mass transfer. In addition to the period increase, there is cyclic period change of 0.023 days over 26.7 years, caused by either a third body with a mass of 0.77 solar masses or magnetic activity cycles. The mass transfer will likely eventually cause the system to evolve into a single star with a very high rotation rate. [13]

Related Research Articles

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<span class="mw-page-title-main">RV Tauri</span> Star in the constellation Taurus

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<span class="mw-page-title-main">16 Cygni Bb</span> Extrasolar planet

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<span class="mw-page-title-main">32 Cygni</span> Binary star system in the constellation Cygnus

32 Cygni is the Flamsteed designation for a binary star system in the Cygnus constellation. It is a 4th magnitude star, which can be seen with the naked eye under suitably dark skies. Parallax measurements give an estimated distance of 1,100 light-years (320 parsecs) from the Earth. However, Schröder et al. (2007) suggest the actual value, after correcting for Malmquist bias, may be closer to 1,174 light-years (360 parsecs). Although it is a spectrsocopic binary with components that cannot be separated visually, it has two entries in the Henry Draper Catalogue, with identical magnitudes and positions, but showing the spectral types of the two components.

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

RT Andromedae is a variable star in the constellation of Andromeda. The system is estimated to be 322 light-years away.

<span class="mw-page-title-main">V404 Cygni</span> Star and black hole binary star system in the constellation Cygnus

V404 Cygni is a microquasar and a binary system in the constellation of Cygnus. It contains a black hole with a mass of about 9 M☉ and an early K giant star companion with a mass slightly smaller than the Sun. The star and the black hole orbit each other every 6.47129 days at fairly close range. Due to their proximity and the intense gravity of the black hole, the companion star loses mass to an accretion disk around the black hole and ultimately to the black hole itself.

<span class="mw-page-title-main">Upsilon Cygni</span> Star in the constellation Cygnus

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<span class="mw-page-title-main">TU Muscae</span> Star in the constellation Musca

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<span class="mw-page-title-main">31 Cygni</span> Triple star system in the constellation Cygnus

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

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<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">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">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">X Cygni</span> Variable star in the constellation Cygnus

X Cygni is a variable star in the northern constellation of Cygnus, abbreviated X Cyg. This is a Delta Cephei variable that ranges in brightness from an apparent visual magnitude of 5.85 down to 6.91 with a period of 16.386332 days. At it brightest, this star is dimly visible to the naked eye. The distance to this star is approximately 628 light years based on parallax measurements. It is drifting further away with a radial velocity of 8.1 km/s. This star is a likely member of the open cluster Ruprecht 173.

<span class="mw-page-title-main">SU Cygni</span> Variable star system in the constellation Cygnus

SU Cygni is a triple star system in the northern constellation of Cygnus, abbreviated SU Cyg. The primary component of the system is a classical Cepheid variable with a period of 3.8455473 days. The changing luminosity of this star causes the system to vary in brightness from a peak apparent visual magnitude of 6.44 down to magnitude 7.22 over the course of its cycle. The distance to this system is approximately 3,200 light years based on parallax measurements. It is a member of the Turner 9 open cluster of stars.

References

  1. ↑ Ostadnezhad, S.; Delband, M.; Hasanzadeh, A. (August 2014). "Photometry, period variations and light curve analysis of eclipsing binary V1191 Cyg". New Astronomy. 31: 14–19. Bibcode:2014NewA...31...14O. doi:10.1016/j.newast.2014.02.001 . Retrieved 22 December 2021.
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  6. ↑ Droege, Thomas F.; Richmond, Michael W.; Sallman, Michael P.; Creager, Robert P. (2006). "TASS Mark IV Photometric Survey of the Northern Sky". Publications of the Astronomical Society of the Pacific. 118 (850): 1666–1678. arXiv: astro-ph/0610529 . Bibcode:2006PASP..118.1666D. doi:10.1086/510197. S2CID   11716917.
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  8. 1 2 3 Pribulla, T.; Vaňko, M.; Chochol, D. R.; Parimucha, Š.; Baluďanský, D. (2005). "Ccd Photometry of the Neglected Contact Binaries V344 Lac and V1191 Cyg". Astrophysics and Space Science. 296 (1–4): 281–284. Bibcode:2005Ap&SS.296..281P. doi:10.1007/s10509-005-4831-2. S2CID   189843557.
  9. ↑ Mayer, P (1965). "Two new variable stars in the Cygnus". Bulletin of the Astronomical Institute of Czechoslovakia. 16: 255–256. Bibcode:1965BAICz..16..255M.
  10. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Ulaş, B.; Kalomeni, B.; Keskin, V.; Köse, O.; Yakut, K. (2012). "Marginally low mass ratio close binary system V1191 Cyg". New Astronomy. 17 (1): 46–49. arXiv: 1107.0277 . Bibcode:2012NewA...17...46U. doi:10.1016/j.newast.2011.06.002. S2CID   119251171.
  11. 1 2 Malkov, O. Yu.; Oblak, E.; Snegireva, E. A.; Torra, J. (2006). "A catalogue of eclipsing variables". Astronomy and Astrophysics. 446 (2): 785–789. Bibcode:2006A&A...446..785M. doi: 10.1051/0004-6361:20053137 .
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  13. 1 2 Zhu, L. Y.; Qian, S. B.; Soonthornthum, B.; He, J. J.; Liu, L. (2011). "Deep, Low Mass Ratio Overcontact Binary Systems. Xi. V1191 Cygni". The Astronomical Journal. 142 (4): 124. Bibcode:2011AJ....142..124Z. doi: 10.1088/0004-6256/142/4/124 .
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