Beta Equulei
Star in the constellation Equuleus
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Beta Equulei, Latinized from β Equulei, is the Bayer designation for a solitary[9] star in the northern constellation of Equuleus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.16.[2] The annual parallax shift is 11.27 mas,[1] indicating a separation of around 289 light years from the Sun. It is drifting closer with a radial velocity of â11 km/s.[6]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Equuleus |
| Right ascension | 21h 22m 53.61365s[1] |
| Declination | +06° 48â² 40.1125â³[1] |
| Apparent magnitude (V) | 5.16[2] |
| Characteristics | |
| Evolutionary stage | Main sequence[3] |
| Spectral type | A3 V[4] |
| UâB color index | +0.10[5] |
| BâV color index | +0.064±0.003[2] |
| Astrometry | |
| Radial velocity (Rv) | â11.1±0.8[6] km/s |
| Proper motion (μ) | RA: +53.685[1] mas/yr Dec.: +10.136[1] mas/yr |
| Parallax (Ï) | 11.2696±0.2608 mas[1] |
| Distance | 289 ± 7 ly (89 ± 2 pc) |
| Absolute magnitude (MV) | +0.13[2] |
| Details | |
| Mass | 2.74±0.04[3] Mâ |
| Radius | 4.02[7] Râ |
| Luminosity | 78.3[2] Lâ |
| Temperature | 9,000[7] K |
| Rotational velocity (v sin i) | 58.0±0.7[4] km/s |
| Age | 600[7] Myr |
| Other designations | |
| β Equ, 10 Equulei, BD+06°4811, HD 203562, HIP 105570, HR 8178, SAO 126749, WDS 21229+0649A[8] | |
| Database references | |
| SIMBAD | data |
This is an ordinary A-type main sequence star with a stellar classification of A3 V.[4] It has 2.7 times the mass of the Sun[3] and about four[7] times the Sun's radius. The star is around 600[7] million years old â 93%[3] of the way through its main sequence lifetime â and is spinning with a projected rotational velocity of 58 km/s.[4] It is radiating 78[2] times the luminosity of the Sun from its photosphere at an effective temperature of about 9,000 K.[7] The star emits an infrared excess indicating the presence of a dusty debris disk. The mean temperature of the dust is 85 K, indicating the semimajor axis of its orbit is 104 AU.[7]
β Equulei has four optical companions. They are not physically associated with the star described above.[10]