18 Sextantis

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18 Sextantis
Sextans constellation map.svg
Red circle.svg
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]
Distance 558 ± 8  ly
(171 ± 3  pc)
Absolute magnitude  (MV)−0.16 [6]
Details
Radius 27.3±1.4 [7]   R☉
Luminosity 222±12 [8]   L☉
Surface gravity (log g)1.72 [9]   cgs
Temperature 4,410±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
SIMBAD data

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]

See also

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References

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