18 Sextantis

18 Sextantis
Location of 18 Sex on the map (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sextans
Right ascension 10h 10m 55.86074s[1]
Declination −08° 25′ 06.4527″[1]
Apparent magnitude (V) 5.62±0.01[2]
Characteristics
Spectral type K2/3 III[3]
U−B color index +1.42[4]
B−V color index +1.30[4]
Astrometry
Radial velocity (Rv)0.2±2.9[5] km/s
Proper motion (μ) RA: −0.115 mas/yr[1]
Dec.: −43.987 mas/yr[1]
Parallax (π)5.8416 ± 0.0881 mas[1]
Distance558 ± 8 ly
(171 ± 3 pc)
Absolute magnitude (MV)−0.16[6]
Details
Radius27.3±1.4[7] R☉
Luminosity222±12[8] L☉
Surface gravity (log g)1.72[9] cgs
Temperature4,410±122[10] K
Metallicity [Fe/H]−0.31+0.01
−0.00[11] dex
Rotational velocity (v sin i)<1.0[12] km/s
Other designations
18 Sex, 32 G. Sextantis[13], BD−07°2977, GC 13990, HD 88333, HIP 49865, HR 3996, SAO 137395, TIC 26206896[14]
Database references
SIMBADdata

18 Sextantis (HD 88333; HR 3996; 32 G. Sextantis), or simply 18 Sex, is a solitary star[15] located in the southern constellation Sextans. It is faintly visible to the naked eye as an orange-hued point of light with an apparent magnitude of 5.62.[2] Gaia DR3 parallax measurements imply a distance of 558 light-years[1] and it is slowly receding with a poorly constrained heliocentric radial velocity of approximately 0.2 km/s.[5] At its current distance, 18 Sex's brightness is diminished with an interstellar extinction of two-tenths of a magnitude[16] and it has an absolute magnitude of −0.16.[6]

18 Sex has a stellar classification of K2/3 III,[3] indicating that it is an evolved star with the characteristics of a K2 and K3 giant star. At present, it has exhausted hydrogen at its core and it has expanded to 27.3 times the radius of the Sun.[7] It radiates 222 times the luminosity of the Sun[8] from its enlarged photosphere at an effective temperature of 4,410 K.[10] Gaia DR3 models it to be a larger and brighter red giant branch star with a radius of 35.27 R☉ and a luminosity of 384 L☉.[1] 18 Sex is metal deficient with an iron abundance of [Fe/H] = −0.31 or 49% of the Sun's[11] and it spins too slowly for its projected rotational velocity to be measured accurately, having a velocity lower than 1.0 km/s.[12]

  1. ^ a b c d e f 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 Houk1999 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Kervella2004 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference McDonald2017 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Poggio2022 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference De Medeiros2014 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Gontcharov2017 was invoked but never defined (see the help page).