Rho Cygni
Star in the constellation Cygnus
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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]
 | |
| 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.