Gamma Persei

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γ Persei
Location of γ Persei (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Perseus
Right ascension 03h 04m 47.82011s[1]
Declination +53° 30′ 23.2626″[1]
Apparent magnitude (V) 2.93[2]
Characteristics
Spectral type G8III + A2V[3]
U−B color index +0.45[2]
B−V color index +0.70[2]
Variable type EA[4]
Astrometry
Radial velocity (Rv)+2.5[5] km/s
Proper motion (μ) RA: −14.194 mas/yr[1]
Dec.: −8.684 mas/yr[1]
Parallax (π)14.735±0.188 mas[6]
Distance221 ± 3 ly
(67.9 ± 0.9 pc)[6]
Absolute magnitude (MV)–1.50[7] (–1.23/0.01)[8]
Orbit[8]
Period (P)14.6 yr
Semi-major axis (a)0.144″
Eccentricity (e)0.785
Inclination (i)90.9°
Longitude of the node (Ω)244.1°
Periastron epoch (T)1991.08 Besselian
Argument of periastron (ω)
(secondary)		170.0°
Details[9]
γ Per A
Mass3.6±0.2 M☉
Radius22.7±1.14 R☉
Luminosity282 L☉
Surface gravity (log g)2.23±0.08 cgs
Temperature4,970±70 K
Metallicity [Fe/H]–0.19[10] dex
Rotation5,350 days[7]
Rotational velocity (v sin i)50.0[7] km/s
γ Per B
Mass2.4±0.2 M☉
Radius3.9±0.2 R☉
Luminosity67.6 L☉
Surface gravity (log g)3.6±0.08 cgs
Temperature8,400±70 K
Other designations
γ Persei, γ Per, Gamma Per, 23 Persei, BD+52 654, CCDM J03048+5331AP, FK5 108, GC 3664, HD 18925, HIP 14328, HR 915, IDS 02576+5307 AP, PPM 28201, SAO 23789, WDS J03048+5330Aa,Ab.
Database references
SIMBADdata

Gamma Persei (Gamma Per, γ Persei, γ Per) is a binary star system in the constellation Perseus. The combined apparent visual magnitude of the pair is +2.9,[2] making it the fourth-brightest member of the constellation. The distance to this system is of roughly 221 light-years (68 parsecs) with a 1% margin of error.[6] About 4° to the north of Gamma Persei is the radiant point for the annual Perseid meteor shower.[11]

Lightcurve of Gamma Persei's 2019 eclipse recorded by NASA's Transiting Exoplanet Survey Satellite (TESS).

This is a wide eclipsing binary system with an orbital period of 5,329.8 days (14.6 years).[12] This eclipse was first observed in 1990 and lasted for two weeks.[13] During an eclipse, the primary passes in front of the secondary, causing the magnitude of the system to decrease by 0.55.[14] The primary component of this system is a giant star with a stellar classification of G9 III.[15] It has a projected rotational velocity of 50.0 km s−1 and a lengthy estimated rotation period of 14.6 years.[7] The classification of the secondary remains tentative, with assignments of A3 V[8] and A2(III).[15]

Mass estimates for the two stars remain disparate. Using speckle interferometry, McAlister (1982) obtained mass estimates of 4.73 M☉ for the primary and 2.75 M☉ for the secondary, where M☉ is the mass of the Sun. He noted that the mass estimate was too high for the given classification of the primary.[16] Martin and Mignard (1998) determined masses for both components based on data from the Hipparcos mission: 5.036 ± 0.951 M☉ for the primary and 2.295 ± 0.453 M☉ for the secondary. They admit that the high inclination of the orbit resulted in a large margin of error.[17] Prieto and Lambert (1999) came up with a mass estimate of 3.81 M☉ for the primary,[18] while Pizzolato and Maggio (2000) obtained 4.34 M☉.[7] Ling et al. (2001) obtained estimates of 2.7 M☉ for the primary and 1.65 M☉ for the secondary,[8] while Kaler (2001) obtained 2.5 and 1.9, respectively.[13] Diamant et al. (2023) found masses of 3.6 and 2.4 M☉ for A and B respectively.[9]

Name and etymology

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References

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  1. ^ a b c 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.
  2. ^ a b c d Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  3. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  4. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  5. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  6. ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gamma Persei's database entry at VizieR.
  7. ^ a b c d e Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  8. ^ a b c d Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  9. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  10. ^ 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. ^ a b 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. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  16. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  17. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  18. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  19. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  20. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日 Archived 2012-02-04 at the Wayback Machine
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