SZ Piscium

A visual band light curve for SZ Piscium, adapted from Eaton et al. (1982)[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Pisces
Right ascension 23h 13m 23.778s[2]
Declination 02° 40′ 31.60″[2]
Apparent magnitude (V) 7.18[3]
Characteristics
Spectral type K1IV + F8V + ?[4]
Variable type EA/DS/RS[3]
Astrometry
Radial velocity (Rv)12.00±2[5] km/s
Proper motion (μ) RA: 23.624 mas/yr[2]
Dec.: 26.346 mas/yr[2]
Parallax (π)10.6705 ± 0.1864 mas[2]
Distance306 ± 5 ly
(94 ± 2 pc)
Orbit[4]
PrimaryK star
CompanionF star
Period (P)3.96566356 d
Semi-major axis (a)15.2 R☉[6]
Eccentricity (e)0 (fixed)
Inclination (i)69.75°
Semi-amplitude (K1)
(primary)		74.2 km/s
Semi-amplitude (K2)
(secondary)		103.98 km/s
Details
K star
Mass1.74[6] M☉
Radius6.0[6] R☉
Luminosity12.3[6] L☉
Temperature4,910[4] K
Rotational velocity (v sin i)3.0±0.6[4] km/s
F star
Mass1.33[6] M☉
Radius1.52[6] R☉
Luminosity3.98[6] L☉
Temperature6,090[4] K
Rotational velocity (v sin i)67.7±1.0[4] km/s
Other designations
SZ Psc, AG+02 2918, BD+01 4695, HD 219113, HIP 114639, SAO 128041, PPM 173881, WDS 23134+0241[7]
Database references
SIMBADdata

SZ Piscium is a suspected triple star[4] system in the equatorial constellation of Pisces. The inner pair form a double-lined spectroscopic binary with an orbital period of 3.966 days.[8] It is a detached Algol-type eclipsing binary of the RS Canum Venaticorum class with a subgiant component. (This means the pair have a close but separated orbit with the stars eclipsing one another, and the primary component is an evolving star showing star spots and other magnetic activity.) The system is too faint to be readily visible to the naked eye with a combined apparent visual magnitude of 7.18.[3] It is located at a distance of approximately 306 light years based on parallax measurements.[2]

The variability of this star was reported by A. Jensch in 1934, who published the first elements.[9] In 1956 the spectrum of the system was examined by N. G. Roman, who found the cooler component is the brighter and more evolved.[10] The system was studied by G. A. Bakos and J. F. Heard in 1958, who found a magnitude of 7.72 for the primary eclipse minimum and 7.30 for the secondary. They refined the class estimates, finding the primary is probably a K1IV subgiant in close orbit with an F8V main sequence star.[11] In 1972, H. L. Atkins and D. S. Hall included it on a list of RS Canum Venaticorum type variable systems and showed it has an infrared excess.[12]

S. Jakate and associates in 1976 found that the period of luminosity variation is changing over time. They discovered strong emission in the H and K lines of the K star and noted that it showed intrinsic variability.[8] The system displayed unusual episodes of emission and variation in the Hα line, which was interpreted by astronomers as ejected material possibly forming a transient disk.[13] The orbital period of the system varies in a 56 year cycle with an amplitude of 4.3×10−4 d, which may be explained by influences of the stellar wind and magnetic activity.[4]

Significant star spot activity was found all over the K-type star, with variations in the total spot coverage observed over time.[6] It is estimated to be filling 85% of its Roche lobe due to the gravitational influence of the secondary. The rotation period of this star is several times slower than its orbital period, while the rotation of the F-type star is synchronous.[4] Changes in radial velocity of the system over time suggest it is a triple star system,[6] with the tertiary component having ~90% of the mass of the Sun and an orbital period of 1,283±10 days.[4]

References

  1. ↑ Eaton, J. A.; Scaltriti, F.; Cerruti-Sola, M.; Sarma, M. B. K.; Ausekar, B. D.; Catalano, S.; Rodono, M. (March 1982). "Light curves of SZ Piscium for 1977 and 1978". Astrophysics and Space Science. 82 (2): 289–306. Bibcode:1982Ap&SS..82..289E. doi:10.1007/BF00651440. S2CID 120020249. Retrieved 24 June 2022.
  2. 1 2 3 4 5 6 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, GCVS 5.1, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  4. 1 2 3 4 5 6 7 8 9 10 Xiang, Yue; et al. (February 2016), "The first Doppler images of the eclipsing binary SZ Piscium", Monthly Notices of the Royal Astronomical Society, 456 (1): 314–322, arXiv:1511.02875, Bibcode:2016MNRAS.456..314X, doi:10.1093/mnras/stv2642.
  5. ↑ 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.
  6. 1 2 3 4 5 6 7 8 9 Eaton, Joel A.; Henry, Gregory W. (March 2007), "The Distribution of Activity on the RS CVn-Type Star SZ Piscium", The Publications of the Astronomical Society of the Pacific, 119 (853): 259–273, Bibcode:2007PASP..119..259E, doi:10.1086/516603, S2CID 14758154.
  7. ↑ "SZ Psc", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-03-21.
  8. 1 2 Jakate, S.; et al. (April 1976), "Eclipsing binary system SZ Piscium", Astronomical Journal, 81: 250–256, Bibcode:1976AJ.....81..250J, doi:10.1086/111880.
  9. ↑ Kang, Young Woon; et al. (October 2003), "Chromospheric activity and unique solution of SZ Psc", Monthly Notices of the Royal Astronomical Society, 344 (4): 1227–1232, Bibcode:2003MNRAS.344.1227K, doi:10.1046/j.1365-8711.2003.06909.x, S2CID 120782775.
  10. ↑ Roman, Nancy G. (March 1956), "Spectral Types of Some Eclipsing Binaries", Astrophysical Journal, 123: 246, Bibcode:1956ApJ...123..246R, doi:10.1086/146155.
  11. ↑ Bakos, G. A.; Heard, J. F. (February 1958), "The eclipsing system, SZ Psc", Astronomical Journal, 63: 302, Bibcode:1958AJ.....63Q.302B, doi:10.1086/107661.
  12. ↑ Atkins, H. L.; Hall, D. S. (October 1972), "Infrared excesses in eclipsing binaries of the RS Canum Venaticorum type", Publications of the Astronomical Society of the Pacific, 84: 638, Bibcode:1972PASP...84..638A, doi:10.1086/129349, S2CID 121175598.
  13. ↑ Ramsey, L. W.; Nations, H. L. (December 1981), "On the nature of H alf outbursts in the RS CVn binary SZ Psc", Publications of the Astronomical Society of the Pacific, 93: 732–734, Bibcode:1981PASP...93..732R, doi:10.1086/130917, S2CID 120698419.

Further reading

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