Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Scorpius |
Right ascension | 17h 36m 32.85514s[1] |
Declination | −38° 38′ 06.8918″[1] |
Apparent magnitude (V) | 4.27±0.01[2] |
Characteristics | |
Evolutionary stage | horizontal branch[3] |
Spectral type | K0 IIIb[4] |
U−B color index | +0.90[5] |
B−V color index | +1.08[5] |
Astrometry | |
Radial velocity (Rv) | −49±3[6] km/s |
Proper motion (μ) | RA: −16.762 mas/yr[1] Dec.: −218.275 mas/yr[1] |
Parallax (π) | 20.6922 ± 0.2161 mas[1] |
Distance | 158 ± 2 ly (48.3 ± 0.5 pc) |
Absolute magnitude (MV) | +0.67[7] |
Details[8] | |
Mass | 1.10±0.07 M☉ |
Radius | 12.39±0.47 R☉ |
Luminosity | 62.2±4.2 L☉ |
Surface gravity (log g) | 2.41±0.11 cgs |
Temperature | 4,605±40 K |
Metallicity [Fe/H] | −0.28±0.02 dex |
Rotational velocity (v sin i) | <1[9] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Q Scorpii, also designated as HD 159433, is an astrometric binary[12] (100% chance)[13] located in the southern zodiac constellation Scorpius. It has an apparent magnitude of 4.27,[2] making it readily visible to the naked eye under ideal conditions. It lies in the tail of Scorpius, between the stars λ Scorpii and μ Scorpii and is located 7′ away from the faint globular cluster Tonantzintla 2. Based on parallax measurements from Gaia DR3, the system is estimated to be 158 light years distant,[1] but is approaching the Solar System with a heliocentric radial velocity of −49 km/s.[6]
The visible component is a red giant with a stellar classification of K0 IIIb.[4] The IIIb luminosity class indicates that it is a lower luminosity giant star. Q Scorpii is a red clump star located on the cool end of the horizontal branch,[3] fusing helium at its core. It has 110% the mass of the Sun but has expanded to 12.4 times its girth.[8] It radiates 62 times the luminosity of the Sun from its photosphere at an effective temperature of 4,605 K,[8] giving it an orange hue. Q Scorpii has an iron abundance half of the Sun's, making it metal deficient.[8] Like most giant stars, it spins slowly, having a projected rotational velocity lower than 1 km/s.[9]