Rho Cygni

Rho Cygni, Latinized from ρ Cygni, is a yellow-hued star in the northern constellation of Cygnus. It is visible to the naked eye with an apparent magnitude of 4.02.^[2] The measured annual parallax shift is 26.39 milliarcseconds,^[1] which yields a distance estimate of 124 light years. It is moving further from the Sun with a radial velocity of +6.88.^[5] The star is a member of the thin disk population of the Milky Way galaxy.^[9]

ρ Cygni

Location of ρ Cygni (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Cygnus
Right ascension	21h 33m 58.85298s[1]
Declination	+45° 35′ 30.6179″[1]
Apparent magnitude (V)	4.02[2]
Characteristics
Evolutionary stage	horizontal branch[3]
Spectral type	G8 III Fe−0.5[4]
U−B color index	+0.56[2]
B−V color index	+0.89[2]
Astrometry
Radial velocity (Rv)	+6.88[5] km/s
Proper motion (μ)	RA: −23.79[1] mas/yr Dec.: −93.70[1] mas/yr
Parallax (π)	26.39±0.15 mas[1]
Distance	123.6 ± 0.7 ly (37.9 ± 0.2 pc)
Absolute magnitude (MV)	1.11[6]
Details
Mass	2.16[7] M☉
Radius	8.19±0.15[8] R☉
Luminosity	37.1[7] L☉
Temperature	5,100[7] K
Metallicity [Fe/H]	−0.05[9] dex
Rotational velocity (v sin i)	0.71[9] km/s
Age	660[9] Myr
Other designations
ρ Cyg, 73 Cygni, BD+44°3865, FK5 1568, GC 30207, HD 205435, HIP 106481, HR 8252, SAO 51035
Database references
SIMBAD	data

This is an evolved giant star of type G with an estimated age of 660^[9] million years and a stellar classification of G8 III Fe-0.5.^[4] The suffix notation indicates the spectrum shows a mild underabundance of iron in the outer atmosphere. It has about 2.16 times the mass of the Sun and 7.81 times the Sun's girth.^[7] The star is radiating 37 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,100 K.^[7]

Rho Cygni is a bright X-ray source with a luminosity of 10.26×10²⁹ ergs s⁻¹.^[10] It has a maximum magnetic field strength of 7.3±0.5 G^[11] at the surface.