Pi Cassiopeiae

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Pi Cassiopeiae
Location of π Cassiopeiae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cassiopeia[1]
Right ascension 00h 43m 28.070s[2]
Declination +47° 01′ 28.36″[2]
Apparent magnitude (V) +4.949[3]
Characteristics
Evolutionary stage Main sequence
Spectral type A5V[4] + A5V[5]
B−V color index +0.171[3]
Variable type Ellipsoidal[6]
Astrometry
Radial velocity (Rv)+12.9±0.8[7] km/s
Proper motion (μ) RA: −24.570 mas/yr[2]
Dec.: −36.886 mas/yr[2]
Parallax (π)18.6293±0.1142 mas[2]
Distance175 ± 1 ly
(53.7 ± 0.3 pc)
Absolute magnitude (MV)+1.30[1]
Orbit[8]
Period (P)1.9642 d
Eccentricity (e)0.00
Periastron epoch (T)2427535.74 JD
Argument of periastron (ω)
(secondary)		0.00°
Semi-amplitude (K1)
(primary)		120.5 km/s
Semi-amplitude (K2)
(secondary)		122.1 km/s
Details
A
Mass1.82[2] M☉
Radius1.9[5] R☉
Luminosity22[9] L☉
Surface gravity (log g)4.41[10] cgs
Temperature8,392±285[10] K
Rotational velocity (v sin i)60[5] km/s
Age251[10] Myr
B
Mass1.87[2] M☉
Radius1.9[5] R☉
Rotational velocity (v sin i)65[5] km/s
Other designations
π Cas, 20 Cas, BD+46°146, HD 4058, HIP 3414, HR 184, SAO 36602[11]
Database references
SIMBADdata

Pi Cassiopeiae is a close binary star[8] system in the constellation Cassiopeia, near the southern border with Andromeda. Its name is a Bayer designation that is Latinized from π Cassiopeiae, and abbreviated Pi Cas or π Cas. This system is visible to the naked eye as a point of light with a combined apparent visual magnitude of +4.949.[3] Based upon an annual parallax shift of 18.63 mas as seen from Earth,[2] this system is located about 175 light-years (54 pc) 175 light years from the Sun. It is drifting further away with a radial velocity of +13 km/s.[7]

A light curve for Pi Cassiopeiae, plotted from TESS data[12]

This is a double-lined spectroscopic binary system with an orbital period of nearly two days in a circular orbit.[8] It is classified as a rotating ellipsoidal variable star and its brightness varies by 0.02 magnitudes with a period of 23.57 hours,[6] which equals half of its orbital period. The spectrum matches that of an A-type main-sequence star with a stellar classification of A5 V.[4] The two stars have similar masses and spectra.[5] A star at a projected separation of 1,700 AU has been identified as a possible white dwarf. It is at the same distance as Pi Cassiopeiae and shares a common proper motion. The age of the white dwarf is calculated to be about 500 million years.[13]

Pi Cassiopeiae has been given the spectral class of kA3hF1mA5, indicating an Am star,[14] but this is now considered doubtful.[15]

References

[edit | edit source]
  1. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). XHIP record for this object at VizieR.
  2. ^ a b c d e f g Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR3 record for this source at VizieR.
  3. ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  4. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  5. ^ a b c d e f Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  6. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  7. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  8. ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  9. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  10. ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  11. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  12. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  13. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  14. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  15. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
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