{{Short description|Triple star system in Sextans}} {{Starbox begin | name = [[Flamsteed designation|35 Sextantis]] }} {{Starbox image | image = {{Location mark | image = Sextans constellation map.svg | float = center | width = 260 | position = right | mark = Red circle.svg | mark_width = 6 | mark_link = 35 Sextantis | x = 188 | y = 328 }} | caption = Location of 35 Sex on the map (circled) }} {{Starbox observe 2s | epoch = [[J2000.0]] ([[International Celestial Reference System|ICRS]]) | constell = [[Sextans]] | component1 = A | ra1 = {{RA|10|43|20.92086}}<ref name = GaiaDR3A/> | dec1 = {{DEC|+04|44|51.6121}}<ref name = GaiaDR3A/> | appmag_v1 = 6.09{{±|0.01}}<ref name = Tycho2000/> | component2 = B | ra2 = {{RA|10|43|20.52732}}<ref name = GaiaDR3B/> | dec2 = {{DEC|+04|44|48.2184}}<ref name = GaiaDR3B/> | appmag_v2 = 7.01{{±|0.01}}<ref name = Tycho2000/> }} {{Starbox character | b-v = +1.17<ref name = Johnson1966/> | u-b = +1.09<ref name = Johnson1966/> }} {{Starbox character|no_heading=y | component1 = A | class = K2.5 III<ref name = Abt1981/> | component2 = B | class2 = K1 II-III<ref name = Lutz1977/> }} {{Starbox astrometry | component1 = A | radial_v = −3.15{{±|0.16}}<ref name = Tokovinin2002/> | parallax = 4.6773 | p_error = 0.1457 | parallax_footnote = <ref name = GaiaDR3A/> | prop_mo_ra = +22.430 | prop_mo_dec = −33.285 | pm_footnote = <ref name = GaiaDR3A/> | absmag_v = | component2 = B | radial_v2 = −1.49{{±|0.98}}<ref name = Tokovinin2002/> | parallax2 = 4.5442 | p_error2 = 0.15 | parallax_footnote2 = <ref name = GaiaDR3B/> | prop_mo_ra2 = +24.384 | prop_mo_dec2 = −37.384 | pm_footnote2 = <ref name = GaiaDR3B/> | absmag_v2 = }} {{Starbox orbit | reference = <ref name = Tokovinin2008/> | primary = A | name = B | axis = 6.80 | axis_unitless = {{val|1460|ul=AU|fmt=commas}} | period = 23,302 }} {{Starbox orbit|no_heading=y | reference = <ref name = Tokovinin2007/> | primary = Ba | name = Bb | axis = 0.021 | axis_unitless = {{val|4.64|ul=AU|fmt=commas}} | period_unitless = {{val|1568.7|2.2|ul=days|fmt=commas}} | periastron = {{val|2451911|27|ul=JD|fmt=commas}} | eccentricity = 0.388{{±|0.057}} | periarg = 311.8{{±|3.3}} | k1 = 5.55{{±|0.15}} }} {{Starbox detail | component1 = A | mass = 2.45<ref name = Tokovinin2008/> | radius = 25.39{{±|0.8|2.2}}<ref name = GaiaDR2A/> | luminosity = 240{{±|7}}<ref name = GaiaDR2A/> | gravity = | temperature = 4,512{{±|122}}<ref name = Stassun2019/> | metal_fe = −0.17<ref name = Anders2019/> | rotational_velocity = 3.7{{±|0.3}}<ref name = Tokovinin2002/> | age_myr = | component2 = Ba | mass2 = 2.44<ref name = Tokovinin2008/> | radius2 = 10.15{{±|0.34|0.30}}<ref name = GaiaDR2B/> | luminosity2 = 57.2{{±|1.2}}<ref name = GaiaDR2B/> | gravity2 = | temperature2 = 5,030{{±|122}}<ref name = Stassun2019/> | metal_fe2 = −0.16<ref name = Anders2019/> | rotational_velocity2 = 4.1{{±|0.5}}<ref name = Tokovinin2002/> | age_myr2 = }} {{Starbox detail|no_heading=y | component1 = Bb | mass = 0.58<ref name = Tokovinin2008/> }} {{Starbox catalog | names = [[Johannes Hevelius|10 H. Sextantis]],<ref name = Verbunt2010/> {{odlist|CCDM = J10433+0443|F = 35 Sex|AG = +05°1556|BD = +05°2384|GC = 14745|HD = 92841|HIP = 52452|HR = 4193|SAO = 118449|TIC = 374350811|WSD = J10433+0445AB|Gould = 68 G. Sextantis<ref name = Gould1879/>}}<ref name = SIMBAD/> }} {{Starbox reference | Simbad = 35+Sex | Simbad2 = 35+Sex+A | Simbad3 = 35+Sex+B | sn = The system | sn2 = A | sn3 = B }} {{Starbox end}}
'''35 Sextantis''' ('''68 G. Sextantis; HD 92841; HR 4193'''), or simply '''35 Sex''', is a [[triple star system]] located in the [[celestial equator|equatorial]] [[constellation]] [[Sextans]]. The primary has an [[apparent magnitude]] of 6.09,<ref name = Tycho2000/> making it barely visible to the [[naked eye]], even under ideal conditions. The companion has an [[apparent magnitude]] of 7.01,<ref name = Tycho2000/> making it readily visible in [[binoculars]], but not to the naked eye. The system is located relatively far at a distance of approximately 700 [[light-year]]s but it is drifting closer with a combined heliocentric [[radial velocity]] of {{val|-2.18|ul=km/s}}.<ref name = Famaey2005/>
==The System== <div style="float:left; width:220px; border:solid black 1px; text-align: center; margin: 8px; padding: 4px; font-size: 90%;"> {{tree chart/start}} {{tree chart|border=1| | |,|S3| |S3='''A''' }} {{tree chart|border=0| | |!|PB|PB=Separation = {{Val|6.8|u=arcsecond}} {{break}} Period = 23,000{{spaces}}y }} {{tree chart|border=1| |-|(|,|S1|S1='''Ba''' }} {{tree chart|border=0| | |`|(|PC|PC= Separation = {{val|0.021|ul=arcsecond}} {{break}} Period = {{Val|1580|u=days|fmt=commas}} }} {{tree chart|border=1| | | |`|S2|S2='''Bb''' }} {{tree chart/end}} Hierarchy of orbits in the 35 Sextantis system<ref name = Tokovinin2007/> </div>
The system was first observed by [[Friedrich Georg Wilhelm von Struve]] in 1821.<ref name = Mason2001/> The separation between the A and B component was initially {{val|7.90|ul=arcseconds}},<ref name = Mason2001/> but it has since decreased to 6.62".<ref name = Heintz1975/> Thanks to this separation, the components 35 Sextantis can be distinguished using a [[telescope]]. Observations from Tokovinin & Gorynya (2007) revealed that the B component is a single-lined [[spectroscopic binary]].<ref name = Tokovinin2007/> The primary and secondary both take 23,302 [[years]] to [[orbit]] each other while the secondary and its close companion take 1,568 [[days]] to revolve around each other in a relatively [[Orbital eccentricity|eccentric]] orbit.<ref name = Tokovinin2007/>
==Physical characteristic== 35 Sextantis A has a [[stellar classification]] of K2.5 III,<ref name = Abt1981/> indicating that it is an [[stellar evolution|evolved]] [[K-type star|K-type]] [[giant star]] that has exhausted [[hydrogen]] at its [[stellar core|core]] and left the [[main sequence]]. 35 Sextantis B has a classification of K1 II-III,<ref name = Lutz1977/> indicating that it is a hotter, more evolved K-type star that has the [[luminosity class]] intermediate between a [[bright giant]] and giant star. The primary has 2.45 times the [[mass of the Sun]]<ref name = Tokovinin2008/> but it has expanded to 25.39 times the [[radius of the Sun]].<ref name = GaiaDR2A/> It radiates 240 times the [[luminosity of the Sun]]<ref name = GaiaDR2A/> from its enlarged [[photosphere]] at an [[effective temperature]] of {{val|4512|ul=K|fmt=commas}},<ref name = Stassun2019/> giving it an orange-hued when viewed in the [[night sky]].
The secondary has a similar mass to the primary<ref name = Tokovinin2008/> but it is smaller, having a radius 10.15 times that of the [[Sun]].<ref name = GaiaDR2B/> 35 Sextantis B radiates 57.2 times the luminosity of the Sun<ref name = GaiaDR2B/> from its photosphere at an effective temperature of 5030 K.<ref name = Stassun2019/> Both stars are metal deficient with [[iron]] abundances of [Fe/H] = −0.17 and [Fe/H] = −0.16 respectively.<ref name = Anders2019/> They spin modestly with [[projected rotational velocity|projected rotational velocities]] of {{val|3.7|ul=km/s}} and 4.1 km/s.<ref name = Tokovinin2002/> The close companion has a mass 58% that of the Sun's,<ref name = Tokovinin2008/> suggesting that it may be a [[K-type main-sequence star]].
==References== {{reflist||refs=
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<ref name = GaiaDR3B>{{Cite DR3|3858258736489910400}}</ref>
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<ref name = GaiaDR2A>{{Cite DR2|3858258736489909632}}</ref>
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}} {{Stars of Sextans}}
[[Category:Triple star systems]] [[Category:Spectroscopic binaries]] [[Category:K-type giants]] [[Category:Sextans]] [[Category:Flamsteed objects|Sextantis, 35]] [[Category:Gould objects|Sextantis, 68]] [[Category:Durchmusterung objects|BD+05 02384]] [[Category:Henry Draper Catalogue objects|092841]] [[Category:Hipparcos objects|052452]] [[Category:Bright Star Catalogue objects|4193]]