Gamma Equulei

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Gamma Equulei
Diagram showing star positions and boundaries of the Equuleus constellation and its surroundings
Cercle rouge 100%.svg

The location of γ Equulei (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Equuleus
Right ascension 21h 10m 20.50005s[1]
Declination 10° 07′ 53.6763″[1]
Apparent magnitude (V) 4.69[2]
Characteristics
Spectral type A9 Sr Eu[3]
U−B color index +0.10[2]
B−V color index +0.26[2]
R−I color index +0.10
Variable type α2 CVn[4]
Astrometry
Radial velocity (Rv) -16.5 ± 0.3 km/s
Proper motion (μ) RA: 48.74[1] mas/yr
Dec.:  mas/yr
Parallax (π) 27.55 ± 0.62[1] mas
Distance 118 ± 3 ly
(36.3 ± 0.8 pc)
Absolute magnitude (MV) 1.97[citation needed]
Details
Radius 2.20 ± 0.12 R
Luminosity 12.8 ± 1.4 L
Surface gravity (log g) 4.47[5] cgs
Temperature 8,574[5] K
Metallicity [Fe/H] +0.68[5] dex
Other designations
γ Equulei, γ Equ, Gamma Equulei, Gamma Equ, 5 Equulei, 5 Equ, BD +9 4732, FK5 1555, HD 201601, HIP 104521, HR 8097, SAO 126593[4]

Gamma Equulei (5 Equulei) is the Bayer designation for a double star[6] in the northern constellation of Equuleus. It is located at a distance of around 118 light-years (36 parsecs) from Earth[1] and has an apparent visual magnitude of 4.7.[2]

The primary component is a chemically peculiar star with a stellar classification of A9 Sr Eu[3] and an apparent magnitude of 4.80.[4] Gamma Equulei undergoes periodic pulsations in luminosity, which places it among the category of roAp stars.[7] The surface magnetic field undergoes long term variation with a period of 91.1 ± 3.6 years, ranging from +577 G to –1,101 G.[8] It has a magnitude 9.05 companion at an angular separation of 1.26 arcseconds.[6]

References

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External links