| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Equuleus [1] |
| Right ascension | 21h 04m 41.64052s [2] |
| Declination | +02° 56′ 32.1874″ [2] |
| Apparent magnitude (V) | 6.41±0.01 [3] |
| Characteristics | |
| Evolutionary stage | horizontal branch [4] |
| Spectral type | K0 III [5] |
| U−B color index | +0.89 [6] |
| B−V color index | +1.06 [6] |
| Astrometry | |
| Radial velocity (Rv) | −12.1±0.2 [7] km/s |
| Proper motion (μ) | RA: +13.336 [2] mas/yr Dec.: +5.800 [2] mas/yr |
| Parallax (π) | 7.5933±0.0353 mas [2] |
| Distance | 430 ± 2 ly (131.7 ± 0.6 pc) |
| Absolute magnitude (MV) | +0.53 [1] |
| Details | |
| Mass | 1.22 [8] M☉ |
| Radius | 10.64±0.54 [9] R☉ |
| Luminosity | 60.59+0.53 −0.52 [2] L☉ |
| Surface gravity (log g) | 2.44 [8] cgs |
| Temperature | 4,815±122 [10] K |
| Metallicity [Fe/H] | −0.21 [11] dex |
| Other designations | |
| 7 G. Equueli [12] , AG+02°2688, BD+02°4297, GC 29434, HD 200661, HIP 104041, HR 8067, SAO 126519 [13] | |
| Database references | |
| SIMBAD | data |
HD 200661 (HR 8067; 7 G. Equueli) is a solitary star located in the equatorial constellation Equuleus, the foal. It has an apparent magnitude of 6.41, [3] placing it near the limit for naked eye visibility. The star is located at a distance of 430 light years based on Gaia DR3 parallax measurements, [2] and it is drifting closer with a heliocentric radial velocity of −12.1 km/s . [7] At its current distance, HD 200661's brightness is diminished by an interstellar extinction of 0.18 magnitude, [14] and it has an absolute magnitude of +0.53. [1]
HD 200661 has a stellar classification of K0 III, [5] indicating that it is an evolved K-type star that has ceased hydrogen fusion at its core and left the main sequence. It has 122% the mass of the Sun, [8] but it has expanded to 10.64 times the radius of the Sun [9] as a result of its evolved state. It radiates 60.59 times the luminosity of the Sun [2] from its enlarged photosphere at an effective temperature of 4815 K , [10] giving it a yellowish-orange hue when viewed in the night sky. HD 200661 is metal deficient with an iron abundance 61.7% that of the Sun's. [11]