Q Scorpii

Q Scorpii
Location of Q Scorpii on the map (circled)
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]
Distance158 ± 2 ly
(48.3 ± 0.5 pc)
Absolute magnitude (MV)+0.67[7]
Details[8]
Mass1.10±0.07 M☉
Radius12.39±0.47 R☉
Luminosity62.2±4.2 L☉
Surface gravity (log g)2.41±0.11 cgs
Temperature4,605±40 K
Metallicity [Fe/H]−0.28±0.02 dex
Rotational velocity (v sin i)<1[9] km/s
Other designations
Q Scorpii, 159 G. Scorpii[10], CD−38°12044, CPD−38°6933, GC 23846, HD 159433, HIP 86170, HR 6546, SAO 209019[11]
Database references
SIMBADdata

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]

  1. ^ a b c d e Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Laney2011 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Hoffleit1937 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Cousins1971 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  8. ^ a b c d Cite error: The named reference Ottoni2022 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference De Medeiros2014 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Frankowski2006 was invoked but never defined (see the help page).