33 Pegasi
Star in the constellation Pegasus
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33 Pegasi is the Flamsteed designation for a visual binary star in the northern constellation of Pegasus. It has an apparent visual magnitude of 6.2,[2] placing it near the limit of naked eye visibility. Measurements show an annual parallax shift of 0.0298125″,[1] which is equivalent to a distance of 109 ly (33 pc) from the Sun. It is drifting further away with a radial velocity of 24 km/s.[2]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 22h 23m 39.565s[1] |
| Declination | +20° 50′ 53.84″[1] |
| Apparent magnitude (V) | 6.203[2] (6.391 + 9.287)[3] |
| Characteristics | |
| Spectral type | F7 V[4] |
| B−V color index | 0.518±0.004[5] |
| Astrometry | |
| Radial velocity (Rv) | 23.8±0.4[2] km/s |
| Proper motion (μ) | RA: +333.057 mas/yr[1] Dec.: −10.827 mas/yr[1] |
| Parallax (π) | 29.8125±0.0436 mas[1] |
| Distance | 109.4 ± 0.2 ly (33.54 ± 0.05 pc) |
| Absolute magnitude (MV) | 3.55[2] |
| Details | |
| 33 Peg A | |
| Mass | 1.28[6] M☉ |
| Radius | 1.29+0.15 −0.14[7] R☉ |
| Luminosity | 2.850+0.007 −0.008[7] L☉ |
| Surface gravity (log g) | 4.29[8] cgs |
| Temperature | 6,169[9] K |
| Metallicity [Fe/H] | −0.18[9] dex |
| Rotational velocity (v sin i) | 6[2] km/s |
| Age | 4.1[9] Gyr |
| 33 Peg B | |
| Mass | 0.80[6] M☉ |
| Other designations | |
| 33 Peg, BD−16°4196, HD 212395, HIP 110548, HR 8532, SAO 90462[10] | |
| Database references | |
| SIMBAD | data |
The primary component of this system is a main sequence star with a visual magnitude of 6.4[3] and a stellar classification of F7 V.[4] It is nearly as old as the Sun with an estimated age of 4.1 billion years, but has a lower abundance of elements other than hydrogen and helium. The star has 1.3 times the mass[6] and radius[7] of the Sun. The stellar atmosphere has an effective temperature of 6,169 K,[9] giving it the yellow-white glow of an F-type star.[11]
A faint, magnitude 9.3 companion star is located at an angular separation of 0.420 arc seconds along a position angle of 0.0°.[3] The pair have a projected separation of 15.6 AU[6] with an orbital period of about 250 years.[12]