YZ Cassiopeiae

YZ Cas
Location of YZ Cassiopeiae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Cassiopeia
A
Right ascension 00h 45m 39.0777s[1]
Declination +74° 59′ 17.063″[1]
Apparent magnitude (V) 5.653[2]
B
Right ascension 00h 45m 42,1503s[3]
Declination +74° 58′ 43.242″[3]
Apparent magnitude (V) 11.23[4]
Characteristics
A
Spectral type A2IV[5] (A1Vm + F2V[6])
U−B color index +0.07[4]
B−V color index +0.05[4]
Variable type Algol[7]
B
Spectral type F2V[8]
U−B color index +0.64[4]
B−V color index +0.94[4]
Astrometry
Radial velocity (Rv)+8.90±0.4[9] km/s
Proper motion (μ) RA: −15.07[1] mas/yr
Dec.: −22.17[1] mas/yr
Parallax (π)11.24 ± 0.55 mas[1]
Distance103.8[8] pc
Absolute magnitude (MV)+0.251[6]
Orbit[10]
CompanionTYC 4307-2168-1
Period (P)86 580 yr
Orbit[8]
PrimaryAa
CompanionAb
Period (P)4.467 days
Semi-major axis (a)17.47 R☉[11]
Eccentricity (e)0.0
Inclination (i)88.332°
Details
Aa
Mass2.308[11] M☉
Radius2.547[11] R☉
Luminosity41.69[11] L☉
Surface gravity (log g)3.988[8] cgs
Temperature9,200[11] K
Rotational velocity (v sin i)29.2[8] km/s
Ab
Mass1.325[12] M☉
Radius1.359[11] R☉
Luminosity3.34[11] L☉
Surface gravity (log g)4.311[8] cgs
Temperature6,890[12] K
Metallicity [Fe/H]+0.10[12] dex
Rotational velocity (v sin i)15.0[8] km/s
Age490 - 550[8] Myr
Other designations
21 Cassiopeiae, HR 192, BD+74 27, HD 4161, SAO 4216, HIP 3572, GC 891, ADS 624 A, CCDM J00457+7459[13]
Database references
SIMBADdata

YZ Cassiopeiae (21 Cas) is a star system 103.8 parsecs (339 ly) away from Earth, in the constellation Cassiopeia. It comprises three stars: an eclipsing Algol-type binary and a visually fainter star about 3000 AU distant.[10]

A light curve for YZ Cassiopeiae, plotted from TESS data[14]

The primary star in the YZ Cassiopeiae system is a white subgiant (main sequence) star of spectral type A1Vm and 2.31 solar masses[10] (M☉) with a less massive main sequence dwarf star of type F2V[2] and 1.35 M☉.[10] The apparent magnitude of the eclipsing binary varies from 5.65 to 6.05[2] with a period of 4.4672 days.[10] Combined, they appear to have a spectral type of A2IV.[10]

The binary has a dimmer (magnitude 9.7 according to Norton,[15] or 10.5 by SIMBAD) companion of 0.8 M☉[10] orbiting with a period of about 86 580 years.[10]

  1. ^ a b c d e Cite error: The named reference hipparcos was invoked but never defined (see the help page).
  2. ^ a b c Jerzy M. Kreiner, Chun-Hwey Kim, Il-Seong Nha. YZ CAS: Atlas of O-C Diagrams of Eclipsing Binary Stars
  3. ^ a b Cite error: The named reference tycho was invoked but never defined (see the help page).
  4. ^ a b c d e Cite error: The named reference eggen was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference grenier was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference bilir was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference gcvs was invoked but never defined (see the help page).
  8. ^ a b c d e f g h Cite error: The named reference pavlovski was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference pulkovo was invoked but never defined (see the help page).
  10. ^ a b c d e f g h Cite error: The named reference Tok was invoked but never defined (see the help page).
  11. ^ a b c d e f g Cite error: The named reference eker was invoked but never defined (see the help page).
  12. ^ a b c Cite error: The named reference maxted was invoked but never defined (see the help page).
  13. ^ "V* YZ Cas". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 26 January 2018.
  14. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Nor was invoked but never defined (see the help page).