29 Cygni
A-type main sequence star in the constellation Cygnus
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29 Cygni is a single[12] star in the northern constellation of Cygnus. It is dimly visible to the naked eye as a white-hued star with an apparent visual magnitude of 4.93.[6] The distance to 29 Cyg, as estimated from an annual parallax shift of 24.5 mas, is 133 light years. The star is moving closer to the Earth with a heliocentric radial velocity of −17 km/s.[6] It is a member of the 30–50 million year old Argus Association of co-moving stars.[13]
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 14m 32.03235s[1] |
| Declination | +36° 48′ 22.7009″[1] |
| Apparent magnitude (V) | 4.94 - 4.97[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3][4] |
| Spectral type | A2 V[5] |
| B−V color index | 0.151±0.018[6] |
| Variable type | δ Sct[7] |
| Astrometry | |
| Radial velocity (Rv) | −17.30±2.80[6] km/s |
| Proper motion (μ) | RA: +68.391[1] mas/yr Dec.: +70.446[1] mas/yr |
| Parallax (π) | 24.5456±0.0724 mas[1] |
| Distance | 132.9 ± 0.4 ly (40.7 ± 0.1 pc) |
| Absolute magnitude (MV) | 1.78[6] |
| Details | |
| Mass | 1.67–1.75[4] M☉ |
| Radius | 1.942±0.055[8] R☉ |
| Luminosity | 25.2+3.7 −3.1[3] L☉ |
| Surface gravity (log g) | 4.14±0.08[8] cgs |
| Temperature | 8,774±113[9] K |
| Rotational velocity (v sin i) | 65[3] km/s |
| Age | 28+15 −14 or 119+37 −10[10] Myr |
| Other designations | |
| b3 Cygni, 29 Cyg, V1644 Cygni, BD+36°3955, HD 192640, HIP 99770, HR 7736, SAO 69678, WDS J20145+3648A, 2MASS J20143203+3648225[11] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
This is an A-type main-sequence star with a stellar classification of A2 V.[5] Rodríguez et al. (2000) classify it as a Delta Scuti variable with a frequency of 0.0267 cycles per day.[7] It is a Lambda Boötis[15] class chemically peculiar star and the first such star to be classified as a pulsating variable.[4] 29 Cyg is multi-periodic,[16] small-amplitude variable with a magnitude change of about 0.02 and a dominant period of 39 minutes.[4] A magnetic field has been detected with an averaged quadratic field of (194.5±230.7)×10−4 T.[17] The star has a moderate rate of rotation,[4] showing a projected rotational velocity of 65 km/s.[3] It has 1.67 to 1.75 the mass of the Sun,[4] 1.942 times the Sun's radius,[8] is radiating 25 times the Sun's luminosity from its photosphere[3] at an effective temperature of roughly 8,774 K.[9]
29 Cygni is listed in multiple star catalogs as having several companions within 4′, including the yellow 7th magnitude HD 192661. All are background objects not physically associated with 29 Cygni itself.[18][1] The naked-eye stars b1 Cygni and b2 Cygni, respectively about one and two degrees away, also lie at different distances to 29 Cygni.
Substellar companion
In 2022, a superjovian planet, HIP 99770 b, was discovered by direct imaging and astrometry. Its spectral class is between L7 and L9.5, corresponding to a surface temperature of 1,400±100 K.[19]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 13.1+4.8 −5.2 MJ |
15.7+3.5 −1.0 |
47+14 −4 |
0.31+0.06 −0.12[10] |
151.3+8.4 −12.0° |
1.056 RJ |