V373 Cassiopeiae

V373 Cassiopeiae

V373 Cassiopeiae (center) in optical light. The bright yellow star to the upper right of V373 Cas is ρ Cas.
Observation data
Epoch J2000      Equinox J2000
Constellation Cassiopeia
Right ascension 23h 55m 33.83878s[1]
Declination +57° 24′ 43.8057″[1]
Apparent magnitude (V) 6.03[2]
Characteristics
Spectral type B0.5II + B4III/V[2]
B−V color index 0.155±0.005[2]
Variable type Eclipsing?[3]
Astrometry
Radial velocity (Rv)−25.5±0.9[4] km/s
Proper motion (μ) RA: −4.098[1] mas/yr
Dec.: −0.101[1] mas/yr
Parallax (π)0.5267 ± 0.0583 mas[1]
Distanceapprox. 6,200 ly
(approx. 1,900 pc)
Orbit[5]
Period (P)13.41921 days
Eccentricity (e)0.126±0.019
Periastron epoch (T)2,420,801.98 JD
Argument of periastron (ω)
(secondary)		16±8°
Semi-amplitude (K1)
(primary)		106.7±2.7 km/s
Semi-amplitude (K2)
(secondary)		144.6±2.6 km/s
Details[6]
A
Mass18.6±2.4 M☉
Surface gravity (log g)3.0±0.2 cgs
Temperature23,200±600 K
Rotational velocity (v sin i)130±10 km/s
Age7–8 Myr
B
Mass14.2±1.9 M☉
Surface gravity (log g)3.5±0.2 cgs
Temperature26,800±1,500 K
Rotational velocity (v sin i)60±5 km/s
Other designations
V373 Cas, BD+56°3115, GC 33184, HD 224151, HIP 117957, HR 9052, SAO 35899[7]
Database references
SIMBADdata

V373 Cas is a binary star system in the northern constellation Cassiopeia. It is a suspected eclipsing binary with an apparent visual magnitude that decreases from a baseline of 6.03 down to 6.13.[3] The system is located at a distance of approximately 6,200 light years from the Sun, but is drifting closer with a radial velocity of around −25.5 km/s.[4]

A visual band light curve for V373 Cassiopeiae, adapted from Lynds (1959)[8]

The binary nature of this system was announced in 1912 by Walter S. Adams.[9] It is a double-lined spectroscopic binary with an orbital period of 13.4 days and an eccentricity of 0.13.[5] The system was found to be variable in 1958 by C. Roger Lynds, and the variability cycle was shown to be related to the orbital period.[9] It has been described as a heartbeat star rather than an eclipsing system. This is a type of pulsating star where the pulsations are induced by the tidal attraction of a close companion.[10]

V373 Cas is composed of two hot blue-white giant stars that have exhausted their core hydrogen and expanded off the main sequence. Lyubimkov and colleagues analysed spectral and radial velocity to calculate that the stars were ~19 and ~15 times as massive as the Sun and the age of the system is around 7-8 million years old.[6] The primary component is the more evolved and now comes close to filling its Roche lobe when it is at periastron.[11]

  1. ^ a b c d e Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Wilson1953 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Hill_Fisher_1987 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Lyubimkov_et_al_1998 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Lynds was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Lynds1959 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference vsx was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Karami_Mohebi_2009 was invoked but never defined (see the help page).