KZ Andromedae

KZ Andromedae

A light curve for KZ Andromedae, plotted from TESS data[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 23h 09m 57.3642s[2]
Declination +35° 32′ 55.65804″[2]
Apparent magnitude (V) 7.91 – 8.03 variable[3]
Characteristics
Spectral type K2Ve+K2Ve[3]
Apparent magnitude (B) 8.81[4]
Apparent magnitude (V) 7.93[4]
Apparent magnitude (G) 7.6580[2]
Apparent magnitude (J) 6.225[5]
Apparent magnitude (H) 5.778[5]
Apparent magnitude (K) 5.659[5]
Variable type BY Dra[3]
Astrometry
Radial velocity (Rv)−5.818±0.026[6] km/s
Proper motion (μ) RA: 150.123±0.063 [2] mas/yr
Dec.: 1.226±0.059[2] mas/yr
Parallax (π)32.8449 ± 0.0369 mas[2]
Distance99.3 ± 0.1 ly
(30.45 ± 0.03 pc)
Orbit[6]
Period (P)3.03291126±0.00000046 days
Eccentricity (e)0.01174±0.00056
Periastron epoch (T)HJD 2455133.480±0.020
Argument of periastron (ω)
(secondary)		7.11±2.35°
Semi-amplitude (K1)
(primary)		69.362±0.046 km/s
Semi-amplitude (K2)
(secondary)		71.300±0.054 km/s
Details[6]
Primary
Radius0.77±0.07 R☉
Luminosity0.34±0.06 L☉
Rotational velocity (v sin i)12.5 km/s
Secondary
Radius0.66±0.06 R☉
Luminosity0.25±0.04 L☉
Rotational velocity (v sin i)12.2 km/s
Other designations
2E 4687, 2MASS J23095734+4757300, BD+47 4058, EUVE J2309+47.9, HD 218738, HIP 114379, GJ 4315, TYC 3627-1822-1, NLTT 2314, SAO 52753, WDS J23100+4758B
Database references
SIMBADdata

KZ Andromedae (often abbreviated to KZ And) is a double lined spectroscopic binary in the constellation Andromeda. Its apparent visual magnitude varies between 7.91 and 8.03 during a cycle slightly longer than 3 days.

System

Both stars in the KZ Andromedae system are main sequence stars of spectral type K2Ve, meaning that the spectrum shows strong emission lines.[3] This is caused by their active chromospheres that cause large spots on the surface.[6]

KZ Andromedae is listed in the Washington Double Star Catalog as the secondary component in a visual binary system, with the primary being HD 218739. In 50 years of observations, there is little evidence of relative motion between the two stars; however, they have a common proper motion and a similar radial velocity.[6]

Variability

The rotational velocity of both stars is consistent with a synchronous rotation of the pair, and the rotational period is itself comparable to the brightness variation period. KX Andromedae is thus classified as a BY Draconis variable, and the variability is caused by the large spots on the surface.[6]

References

  1. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  2. ^ a b c d e f 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. ^ a b c d N. N. Samus; O. V. Durlevich; et al. "KZ And database entry". Combined General Catalog of Variable Stars (2004 ed.). CDS. Retrieved 2018-11-12.
  4. ^ a b "KZ And". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 12, 2018.
  5. ^ a b c Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
  6. ^ a b c d e f Fekel, F. C.; Henry, G. W.; Tomkin, J. (September 2017). "New Precision Orbits of Bright Double-lined Spectroscopic Binaries. X. HD 96511, HR 7578, and KZ Andromedae". The Astronomical Journal. 154 (3): 13. Bibcode:2017AJ....154..120F. doi:10.3847/1538-3881/aa816e. 120.