View source for HD 168443

{{short description|Star in the constellation Serpens}}
{{starbox begin}}
{{starbox observe
 | epoch       = J2000.0
 | constell    = [[Serpens]]<ref name=Anderson_Francis_2012/>
 | ra          = {{RA|18|20|03.93329}}<ref name="Gaia DR3"/>
 | dec         = {{DEC|-09|35|44.6146}}<ref name="Gaia DR3"/>
 | appmag_v    = 6.92<ref name=Anderson_Francis_2012/>
}}
{{starbox character
 | type        =
 | class       = G6V<ref name=Gray_et_al_2006/>
 | b-v         = {{val|0.724|0.014}}<ref name=Anderson_Francis_2012/>
 | variable    =
}}
{{Starbox astrometry
 | radial_v    = {{val|−48.69|0.10}}<ref name=Anderson_Francis_2012/>
 | prop_mo_ra  = {{val|-91.792|0.036}}
 | prop_mo_dec = {{val|-223.979|0.030}}
 | pm_footnote = <ref name="Gaia DR3"/>
 | parallax    = 25.5913
 | p_error     = 0.0410
 | parallax_footnote = <ref name="Gaia DR3"/>
 | absmag_v    = 4.198<ref name=Pilyavsky_et_al_2011/>
}}
{{Starbox detail
 | source      = <ref name=Pilyavsky_et_al_2011/>
 | mass        = {{val|0.995|0.019}}
 | radius      = {{val|1.51|0.06}}
 | luminosity  = {{val|2.413|0.009}}<ref name="Gaia DR2">{{Cite Gaia DR2|4157584215800708736}}</ref>
 | gravity     = {{val|4.07|0.06}}
 | temperature = {{Val|5491|44|fmt=commas}}
 | metal_fe    = {{val|+0.04|0.03}}
 | rotation    =
 | rotational_velocity = {{val|2.20|0.50}}
 | age_gyr     = {{val|11.3|1.0|0.8}}<ref name=Anderson_Francis_2012/>
}}
{{starbox catalogue
 | names = {{odlist | BD=−09°4692 | GJ=4052 | HD=168443 | HIP=89844 | LTT=7289 | SAO=142228 }}<ref name=SIMBAD/>
}}
{{starbox reference
 | Simbad = HD+168443
 | NSTED = HD+168443
}}
{{starbox end}}

'''HD 168443''' is an ordinary yellow-hued [[star]] in the Serpens Cauda segment of the [[celestial equator|equatorial]] [[constellation]] of [[Serpens]]. It is known to have two substellar companions. With an [[apparent visual magnitude]] of 6.92,<ref name=Anderson_Francis_2012/> the star lies just below the nominal lower brightness limit of visibility to the normal human eye. This system is located at a distance of 127&nbsp;[[light year]]s from the [[Sun]] based on [[stellar parallax|parallax]],<ref name="Gaia DR3"/> but is drifting closer with a [[radial velocity]] of −48.7&nbsp;km/s.<ref name=Anderson_Francis_2012/>

This stellar object is a [[stellar core|core]] [[hydrogen fusion|hydrogen fusing]] [[G-type main-sequence star]] with a [[stellar classification|classification]] of G6V, although it is likely [[stellar evolution|evolved]]<ref name=Pilyavsky_et_al_2011/> with an age of around 11&nbsp;billion years.<ref name=Anderson_Francis_2012/> It is slightly lower in mass than the Sun but has a radius that is larger by 51%. The star is spinning with a leisurely [[projected rotational velocity]] of 2.2&nbsp;km/s<ref name=Pilyavsky_et_al_2011/> and it has a very [[chromospheric activity|inactive chromosphere]].<ref name=Gray_et_al_2006/><ref name=Pilyavsky_et_al_2011/> It is radiating 2.4<ref name="Gaia DR2"/> times the [[luminosity of the Sun]] from its [[photosphere]] at an [[effective temperature]] of 5,491&nbsp;K.<ref name=Pilyavsky_et_al_2011/>
== Planetary system ==
HD 168443 is known to be orbited by a [[super-Jupiter]] [[exoplanet]], discovered in 1999, and a [[brown dwarf]], discovered in 2001. The brown dwarf takes 30 times longer to orbit the star than the planet.<ref name="Marcy1999"/><ref name="Marcy2001"/><ref name="Reffert2006"/> Both have eccentric orbits.<ref name=Pilyavsky_et_al_2011/> An orbital fit to [[Hipparcos]] astrometric data suggested the brown dwarf has a mass of {{val|34|12|ul=Jupiter mass}}.<ref name="Reffert2006"/> A 2022 study utilizing both Hipparcos and [[Gaia (spacecraft)|Gaia]] data instead measured a true mass of {{Jupiter mass|17.3}} for HD 168443 c, close to the minimum mass.<ref name="Feng2022"/> Test simulations of massless particles orbiting in between these two bodies show that all such objects are quickly ejected within two million years. That suggests any other planetary companions would be orbiting further out from the star.<ref name=Barnes2004/>

{{OrbitboxPlanet begin
 | table_ref    = 
 | period_unit  = year
}}
{{OrbitboxPlanet
 | exoplanet    = [[HD 168443 b|b]]
 | mass         = {{val|7.659|0.0975|p=≥}}<ref name=Pilyavsky_et_al_2011/>
 | semimajor    = {{val|0.2931|0.00181}}<ref name=Pilyavsky_et_al_2011/>
 | period       = {{val|0.1591010|(11)}}<ref name=An2025/>
 | eccentricity = {{val|0.5288|0.0020|0.0021}}<ref name=An2025/>
}}
{{OrbitboxPlanet
 | exoplanet    = c<ref name=An2025/>
 | mass         = {{val|20.5|1.6}}
 | semimajor    = {{val|2.929|0.040|0.045}}
 | period       = {{val|4.8164|0.0052|0.0030}}
 | eccentricity = {{val|0.2131|0.0034}}
 | inclination  = {{val|117|6|10}}
}}
{{Orbitbox end}}

==See also==
* [[HD 38529]]
* [[List of exoplanets discovered before 2000]] - HD 168443 b
* [[List of exoplanets discovered between 2000–2009]] - HD 168443 c

==References==
{{Reflist|refs=

<ref name="Gaia DR3">{{Cite Gaia DR3|4157584215800708736}}</ref>

<ref name=SIMBAD>{{cite simbad
 | title=HD 168443 | access-date=2020-12-06 }}</ref>

<ref name=Anderson_Francis_2012>{{cite journal
 | last1=Anderson | first1=E. | last2=Francis | first2=Ch.
 | title=XHIP: An extended hipparcos compilation
 | journal=Astronomy Letters
 | volume=38 | issue=5 | pages=331 | year=2012
 | bibcode=2012AstL...38..331A | arxiv=1108.4971
 | doi=10.1134/S1063773712050015 | s2cid=119257644 }}</ref>

<ref name=Barnes2004>{{cite journal
 | title=Predicting Planets in Known Extrasolar Planetary Systems. I. Test Particle Simulations
 | last1=Barnes | first1=Rory | last2=Raymond | first2=Sean N.
 | journal=The Astrophysical Journal
 | volume=617 | issue=1 | pages=569–574 | date=December 2004
 | arxiv=astro-ph/0402542 | bibcode=2004ApJ...617..569B
 | doi=10.1086/423419 | s2cid=12380925 }}</ref>

<ref name=Pilyavsky_et_al_2011>{{cite journal
 | title=A Search for the Transit of HD 168443b: Improved Orbital Parameters and Photometry
 | last1=Pilyavsky | first1=Genady | last2=Mahadevan | first2=Suvrath
 | last3=Kane | first3=Stephen R. | last4=Howard | first4=Andrew W.
 | last5=Ciardi | first5=David R. | last6=de Pree | first6=Chris
 | last7=Dragomir | first7=Diana | last8=Fischer | first8=Debra
 | last9=Henry | first9=Gregory W. | last10=Jensen | first10=Eric L. N.
 | last11=Laughlin | first11=Gregory | last12=Marlowe | first12=Hannah
 | last13=Rabus | first13=Markus | last14=von Braun | first14=Kaspar
 | last15=Wright | first15=Jason T. | last16=Wang | first16=Xuesong X.
 | display-authors=1 | journal=The Astrophysical Journal
 | volume=743 | issue=2 | id=162 | pages=8 | date=December 2011
 | arxiv=1109.5166 | bibcode=2011ApJ...743..162P
 | doi=10.1088/0004-637X/743/2/162 | s2cid=13190486 }}</ref>

<ref name=An2025>{{cite journal |last=An |first=Qier |last2=Brandt |first2=Timothy D. |last3=Brandt |first3=G. Mirek |last4=Venner |first4=Alexander |title=Orbits and Masses for 156 Companions from Combined Astrometry and Radial Velocities, and A Validation of Gaia Non-Single Star Solutions |date=2025-08-11 |journal=[[The Astrophysical Journal Supplement Series]] |arxiv=2508.08374}}</ref>

<ref name=Gray_et_al_2006>{{cite journal
 | title=Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample
 | last1=Gray | first1=R. O. | last2=Corbally | first2=C. J.
 | last3=Garrison | first3=R. F. | last4=McFadden | first4=M. T.
 | last5=Bubar | first5=E. J. | last6=McGahee | first6=C. E.
 | last7=O'Donoghue | first7=A. A. | last8=Knox | first8=E. R.
 | display-authors=1 | journal=The Astronomical Journal
 | volume=132 | issue=1 | pages=161–170 |date=July 2006
 | doi=10.1086/504637 | bibcode=2006AJ....132..161G
 | arxiv=astro-ph/0603770 | s2cid=119476992 }}</ref>

<ref name="Marcy1999">{{cite journal
 | title=Two New Planets in Eccentric Orbits
 | last1=Marcy | first1=Geoffrey W. | last2=Butler | first2=R. Paul
 | last3=Vogt | first3=Steven S. | last4=Fischer | first4=Debra
 | last5=Liu | first5=Michael C. | display-authors=1
 | journal=The Astrophysical Journal
 | volume=520 | issue=1 | pages=239–247 | year=1999
 | arxiv=astro-ph/9904275 | bibcode=1999ApJ...520..239M
 | doi=10.1086/307451 | s2cid=16827678 }}</ref>

<ref name="Marcy2001">{{cite journal
 | title=Two Substellar Companions Orbiting HD 168443
 | last1=Marcy | first1=Geoffrey W. | last2=Butler | first2=R. Paul
 | last3=Vogt | first3=Steven S. | last4=Liu | first4=Michael C.
 | last5=Laughlin | first5=Gregory | last6=Apps | first6=Kevin
 | last7=Graham | first7=J. R. | last8=Lloyd | first8=J.
 | last9=Luhman | first9=Kevin L. | first10=Ray | last10=Jayawardhana
 | display-authors=1 | journal=The Astrophysical Journal
 | volume=555 | issue=1 | pages=418–425 | year=2001
 | bibcode=2001ApJ...555..418M | doi=10.1086/321445 | doi-access=free }}</ref>

<ref name="Reffert2006">{{cite journal
 | title=Hipparcos astrometric orbits for two brown dwarf companions: HD 38529 and HD 168443
 | url=https://www.aanda.org/articles/aa/full/2006/14/aa4611-05/aa4611-05.html
 | last1=Reffert | first1=S. | last2=Quirrenbach | first2=A.
 | journal=Astronomy and Astrophysics
 | volume=449 | issue=2 | pages=699–702 | year=2006
 | bibcode=2006A&A...449..699R | doi=10.1051/0004-6361:20054611 | doi-access=free | hdl=1887/7483 | hdl-access=free }}</ref>

<ref name="Feng2022">{{cite journal |last1=Feng |first1=Fabo |last2=Butler |first2=R. Paul |display-authors=etal |date=August 2022 |title=3D Selection of 167 Substellar Companions to Nearby Stars |journal=[[The Astrophysical Journal Supplement Series]] |volume=262 |issue=21 |page=21 |doi=10.3847/1538-4365/ac7e57 |arxiv=2208.12720 |bibcode=2022ApJS..262...21F |s2cid=251864022 |doi-access=free }}</ref>

}}

==External links==
* {{cite press release | title=Two new planetary systems discovered | date=January 9, 2001 | publisher=W. M. Keck Observatory | location=Kamuela, Hawaii | url=http://www.keckobservatory.org/two_new_planetary_systems_discovered/ | access-date=August 13, 2019 }}
* {{cite encyclopedia | url=http://exoplanet.eu/star.php?st=HD+168443 | archive-url=https://web.archive.org/web/20071106054825/http://exoplanet.eu/star.php?st=HD+168443 | url-status=dead | archive-date=November 6, 2007 | encyclopedia=[[Extrasolar Planets Encyclopaedia]] | title=Notes for star HD 168443 | access-date=2008-09-08}}

{{Stars of Serpens}}
<!-- Properties -->
{{DEFAULTSORT:HD 168443}}
[[Category:G-type main-sequence stars]]
[[Category:Brown dwarfs]]
[[Category:Planetary systems with two confirmed planets]]
<!-- Identifiers -->
[[Category:Serpens]]
[[Category:Durchmusterung objects]]
[[Category:Gliese and GJ objects|4052]]
[[Category:Henry Draper Catalogue objects|168443]]
[[Category:Hipparcos objects|089844]]