UV Piscium

UV Piscium

A light curve for UV Piscium plotted from TESS data
Observation data
Epoch J2000      Equinox ICRS
Constellation Pisces
Right ascension 01h 16m 55.119s
Declination +06° 48′ 42.13″
Apparent magnitude (V) 8.98
Characteristics
Primary
Evolutionary stage Main sequence
Spectral type G5V
B−V color index 0.65±0.02
Variable type Detached Algol + RS CVn
Secondary
Evolutionary stage Main sequence
Spectral type K3V
B−V color index 1.04±0.07
Astrometry
Radial velocity (Rv)6.45±0.40 km/s
Proper motion (μ) RA: +85.250 mas/yr
Dec.: +20.946 mas/yr
Parallax (π)14.0593±0.0236 mas
Distance232.0 ± 0.4 ly
(71.1 ± 0.1 pc)
Absolute magnitude (MV)4.48±0.05
Orbit
Period (P)0.86104716 d
Eccentricity (e)0.0 (assumed)
Inclination (i)88.9±2.0°
Periastron epoch (T)2,448,897.4226±0.0003 HJD
Semi-amplitude (K1)
(primary)		117.20±0.18 km/s
Semi-amplitude (K2)
(secondary)		154.81±0.37 km/s
Details
Primary
Mass1.0225±0.0058 M☉
Radius1.096 R☉
Surface gravity (log g)4.340±0.018 cgs
Temperature5,780±100 K
Metallicity [Fe/H]0.025±0.066 dex
Rotation0.86 d
Rotational velocity (v sin i)71.01+0.37
−0.36 km/s
Age4.7 Gyr
Secondary
Mass0.7741±0.0034 M☉
Radius0.829 R☉
Surface gravity (log g)4.478±0.019 cgs
Temperature4,750±80 K
Rotation0.86 d
Rotational velocity (v sin i)51.66+1.25
−1.20 km/s
Other designations
UV Psc, BD+06°189, HD 7700, HIP 5980, SAO 109778
Database references
SIMBADdata

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.

This star was found to be variable by H. Huth in 1959. He determined it to be an eclipsing binary and published the first light curve with a period of 20.67 hours. R. B. Carr in 1969 proposed this to be an Algol-type variable with a minor tidal distortion of the components, plus a large, anomalous asymmetry in the light curve. D. S. Hall in 1976 grouped it among the class of short-period RS CVn binaries. The following year, variable, non-thermal radio emission was detected coming from this system, the first such discovered for a short-period binary.

Daniel M. Popper in 1969 found a double-lined, G-type spectrum with both components showing emission in the H and K lines. In 1979, A. R. Sadik deduced the system is a detached binary and suggested a bright, hot spot may produce the observed asymmetry in the light curve. He found stellar classifications of G2V and K0IV for the primary and secondary components, respectively. With improved spectra, Popper found main sequence classes of G5 and K3 for the two stars. The presence of a prominence was deduced in 1992, and a flare of hydrogen alpha was observed the following year.

This is a close binary system with an orbital period of 0.86 days. The orbit is circular and the components are spinning rapidly in-sync with their orbital period. This rotation rate is making both stars magnetically active, with average magnetic field strengths of 137 G and 88 G for the primary and secondary, respectively. Magnetic activity cycles appear to be causing the orbital period to oscillate with a 61 year period. The primary is a G-type main-sequence star of about the same size and mass as the Sun, while the secondary is a smaller K-type main-sequence star. They are estimated to be about 4.6 billion years old.

References

  1. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  2. 1 2 3 4 5 6 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.
  3. 1 2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  4. 1 2 3 4 5 6 7 Popper, Daniel M. (September 1997), "Orbits of detached main-sequence eclipsing binaries of types late F to K. II. UV Leonis, UV Piscium, and BH Virginis", The Astronomical Journal, 114: 1195, Bibcode:1997AJ....114.1195P, doi:10.1086/118552.
  5. ↑ 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.
  6. 1 2 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, arXiv:astro-ph/0404219, Bibcode:2004MNRAS.349.1069K, doi:10.1111/j.1365-2966.2004.07588.x, S2CID 15290475.
  7. 1 2 3 Hahlin, A.; et al. (June 2021), "Magnetic field of the eclipsing binary UV Piscium", Astronomy & Astrophysics, 650: 17, arXiv:2105.02542, Bibcode:2021A&A...650A.197H, doi:10.1051/0004-6361/202140832, S2CID 233864794, A197.
  8. ↑ Qian, S. -B.; et al. (March 2018), "Physical Properties and Evolutionary States of EA-type Eclipsing Binaries Observed by LAMOST", The Astrophysical Journal Supplement Series, 235 (1): 12, arXiv:1712.09026, Bibcode:2018ApJS..235....5Q, doi:10.3847/1538-4365/aaa601, S2CID 119102391, 5.
  9. ↑ "UV Psc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 8 July 2022.
  10. ↑ Herr, Richard B. (April 1969), "Identification List of Spectroscopic and Eclipsing Binaries Subject to Occultations by the Moon", Publications of the Astronomical Society of the Pacific, 81 (479): 105, Bibcode:1969PASP...81..105H, doi:10.1086/128748, S2CID 123513287.
  11. ↑ Huth, H. (1959), Mitteilungen über Veränderliche Sterne, 424.
  12. 1 2 Sadik, A. R. (July 1979), "Light and Colour Curve Observations and Analysis of the Short Period Eclipsing Binary System UV Psc", Astrophysics and Space Science, 63 (2): 319–349, Bibcode:1979Ap&SS..63..319S, doi:10.1007/BF00638905, S2CID 122684321.
  13. ↑ Hall, D. S. (1976), "The RS CVN Binaries and Binaries with Similar Properties", in Fitch, W. S. (ed.), Multiple Periodic Variable Stars, Proceedings of IAU Colloq. 29, held in Budapest, Hungary, 1–5 September 1975, Astrophysics and Space Science Library, vol. 60, D. Reidel Publishers, p. 287, Bibcode:1976ASSL...60..287H, doi:10.1007/978-94-010-1175-4_15, ISBN 978-94-010-1177-8, S2CID 120775716.
  14. ↑ Spangler, S. R.; et al. (December 1977), "Radio survey of close binary stars", Astronomical Journal, 82: 989–997, Bibcode:1977AJ.....82..989S, doi:10.1086/112161.
  15. ↑ Popper, Daniel M. (June 1969), "Twelve Eclipsing Binaries with Double-Lined Spectra", Bulletin of the American Astronomical Society, 1: 257, Bibcode:1969BAAS....1R.257P.
  16. ↑ Liu, Quingyao; et al. (April 1996), "A H-alpha Flare on UV Piscium", Information Bulletin on Variable Stars, 4326: 1, Bibcode:1996IBVS.4326....1L.
  17. ↑ Qian, Shengbang; et al. (1999), "Orbital period studies of the RS CVn-type binaries. II. UV Piscium", Astrophysics and Space Science, 266 (4): 529–538, Bibcode:1999Ap&SS.266..529Q, doi:10.1023/A:1002030722350.

Further reading