25 Scorpii
Star in the constellation Scorpius
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25 Scorpii (abbreviated to 25 Sco) is a star in the zodiac constellation of Scorpius, located about 920 light years away from the Sun. Its apparent magnitude is 6.71,[3] so its apparent brightness is at the limit of human eyesight and can only be seen under excellent conditions, according to the Bortle scale. The object is moving closer to the Earth with a heliocentric radial velocity of −1.3 km/s.[2] It is a proposed member of the Scorpius–Centaurus association.[7]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Scorpius[1] |
| Right ascension | 16h 46m 51.34498s[2] |
| Declination | −25° 31′ 42.8647″[2] |
| Apparent magnitude (V) | 6.71[3] |
| Characteristics | |
| Spectral type | K0 II[4] |
| B−V color index | +1.18[3] |
| Astrometry | |
| Radial velocity (Rv) | −1.31±0.14[2] km/s |
| Proper motion (μ) | RA: −4.165[2] mas/yr Dec.: −15.630[2] mas/yr |
| Parallax (π) | 3.5599±0.0433 mas[2] |
| Distance | 920 ± 10 ly (281 ± 3 pc) |
| Absolute magnitude (MV) | 0.09[1] |
| Details | |
| Mass | 2.075+0.709 −0.993[5] M☉ |
| Radius | 12.719+2.800 −1.943[5] R☉ |
| Luminosity | 135[6] L☉ |
| Surface gravity (log g) | 2.509+0.135 −0.351[5] cgs |
| Temperature | 4777+76 −133[5] K |
| Metallicity [Fe/H] | −0.031+0.150 −0.480[5] dex |
| Other designations | |
| 25 Sco, CD−25°11667, FK5 5482, HD 151179, HIP 82140, HR 6225, SAO 184630 | |
| Database references | |
| SIMBAD | data |
This is an evolved bright giant with a spectral type of K0 II.[4] It is about two times more massive and over twelve times wider than the Sun.[5] The star is radiating 135 times the Sun's luminosity[6] from its photosphere at an effective temperature of about 4,700 K.[5]