52 Cygni
Binary star system in the constellation Cygnus
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52 Cygni is a giant star in the northern constellation of Cygnus with an apparent magnitude of 4.22. Based on its Hipparcos parallax, it is about 291 light-years (89 pc) away.
 | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Cygnus[1] |
| A | |
| Right ascension | 20h 45m 39.75304s[2] |
| Declination | +30° 43′ 10.9756″[2] |
| Apparent magnitude (V) | 4.22[3] |
| B | |
| Right ascension | 20h 45m 40.206s[4] |
| Declination | +30° 43′ 12.96″[4] |
| Apparent magnitude (V) | 11.06[4] |
| Characteristics | |
| Evolutionary stage | red clump[5] |
| Spectral type | G9.5III[6] |
| U−B color index | +0.88[3] |
| B−V color index | +1.05[3] |
| Astrometry | |
| Radial velocity (Rv) | –0.72[7] km/s |
| Proper motion (μ) | RA: –8.98[2] mas/yr Dec.: +24.11[2] mas/yr |
| Parallax (π) | 16.22±0.19 mas[2] |
| Distance | 201 ± 2 ly (61.7 ± 0.7 pc) |
| Absolute magnitude (MV) | +0.27[1] |
| Details | |
| Mass | 2.07[5] M☉ |
| Radius | 13.81[5] R☉ |
| Luminosity | 89[8] L☉ |
| Surface gravity (log g) | 2.5[8] cgs |
| Temperature | 4,677[8] K |
| Metallicity [Fe/H] | −0.24[8] dex |
| Rotational velocity (v sin i) | 3.7[8] km/s |
| Age | 2.27[5] Gyr |
| Other designations | |
| ADS 14259, BD+30 4167, WDS J20456+3043, CCDM J20457+3043 | |
| A: HR 7942, HD 197912, HIP 102453, SAO 70467 | |
| B: TYC 2687-2652-1 | |
| Database references | |
| SIMBAD | A |
| B | |
52 Cygni is a probable horizontal branch (red clump) star, fusing helium in its core, although there is a 25% chance that it is still on the red giant branch (RGB) and fusing hydrogen in a shell around an inert core. As a clump giant it would be 2.27 billion years old, but only 910 million years if 52 Cygni is an RGB star.[5] It shines with a bolometric luminosity of about 90 L☉ at an effective temperature of 4,677 K.[8] It has a radius of about 14 R☉.[5]
At an angular separation of 6.0″ from 52 Cygni is a faint magnitude 9.5 companion.[6]
It was once designated k Cygni by John Flamsteed and was included in his Atlas Coelestis, but the designation is now dropped.[9]