{{Short description|Star in the constellation Centaurus}} {{Starbox begin|name=HD 102117 / Uklun}} {{Starbox observe | epoch = J2000 | constell = [[Centaurus (constellation)|Centaurus]]<ref name=Anderson_Francis_2012/> | ra = {{RA|11|44|50.46086}}<ref name=GaiaDR3/> | dec = {{DEC|−58|42|13.3580}}<ref name=GaiaDR3/> | appmag_v = 7.47<ref name=Anderson_Francis_2012/> }} {{Starbox character | type = [[subgiant]]<ref name=GaiaDR3/> | class = G6V<ref name=houk1975/> | b-v = {{val|0.721|0.009}}<ref name=Anderson_Francis_2012/> | variable = Constant<ref name="Tinney2005"/> }} {{Starbox astrometry | radial_v = {{val|+49.52|0.12}}<ref name=GaiaDR3/> | prop_mo_ra = −63.574 | prop_mo_dec = −70.331 | pm_footnote = <ref name=GaiaDR3/> | parallax = 25.3531 | p_error = 0.0178 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = 4.48<ref name=Anderson_Francis_2012/> }} {{Starbox detail | source = | mass = {{val|1.37|0.130|u=solar mass}}<ref name=apj22159_1_141/><br/>{{val|1.03|0.05}}<ref name="Lovis2005"/> | radius = 1.27<ref name=spocs/> | luminosity = 1.54<ref name=spocs/> | gravity = {{val|4.37|0.06}}<ref name=spocs/> | temperature = {{val|5695|44|fmt=commas}}<ref name=apj22159_1_141/> | metal_fe = {{val|0.30|0.03}}<ref name="Lovis2005"/> | rotational_velocity = {{val|0.88|0.5}}<ref name=spocs/> | age_gyr = {{val|5.3|3.4}}<ref name=apj22159_1_141/> }} {{Starbox catalog | names = {{odlist | name=Uklun | HD=102117 | CD=−58°4207 | HIP=57291 | SAO=239348 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = HD+102117 | NSTED = HD-102117 }} {{Starbox end}}

'''HD 102117''' or '''Uklun''' {{IPAc-en|ˈ|ʌ|k|l|ə|n}} is a [[star]] in the southern [[constellation]] of [[Centaurus]]. With an [[apparent visual magnitude]] of 7.47,<ref name=Anderson_Francis_2012/> it is too dim to be seen without [[binoculars]] or a small [[telescope]]. It is located at a distance of approximately 129&nbsp;[[light-year]]s from the [[Sun]] based on [[stellar parallax|parallax]]. HD 102117 is drifting further away with a [[radial velocity]] of +50&nbsp;km/s,<ref name=GaiaDR3/> having come to within {{convert|13.45|pc|ly|disp=out|abbr=off}} some 692,000&nbsp;years ago.<ref name=Anderson_Francis_2012/> It has one known planet.<ref name="Lovis2005"/>

The [[stellar classification]] of HD 102117 is G6V,<ref name=Houk1979/> which matches the [[stellar spectrum|spectrum]] of an ordinary [[G-type main-sequence star]]. It is roughly five<ref name=apj22159_1_141/>&nbsp;billion years old and is spinning with a [[projected rotational velocity]] of 0.9&nbsp;km/s.<ref name=spocs/> The star shows only a low level of [[chromospheric activity]]<ref name="Lovis2005"/> and is [[Photometry (astronomy)|photometrically]] stable,<ref name="Tinney2005"/> meaning it doesn't vary significantly in brightness. It appears [[metallicity|metal-enriched]],<ref name="Tinney2005"/> showing a higher abundance of heavy elements compared to the Sun.

==Planetary system== In 2004, the [[Anglo-Australian Planet Search]] announced a planet orbiting the star.<ref name="Tinney2005"/> A short time later the [[HARPS]] team also announced the presence of a planet around this star. Both groups detected this planet with the [[radial velocity method]].<ref name="Lovis2005"/>

HD 102117, and its planet HD 102117b, were chosen as part of the 2019 [[NameExoWorlds]] campaign organised by the [[International Astronomical Union]], which assigned each country a star and planet to be named. HD 102117 was assigned to [[Pitcairn Islands]]. The winning proposal named the star '''Uklun''', from the word ''aklan'' 'we/us' in the [[Pitcairn language]], and the planet '''Leklsullun''' {{IPAc-en|l|E|k|@l|s|V|l|@|n}}, from the phrase ''lekl salan''<!--"Little" is found as ''likl, letl, lekl,'' even ''ookl''.--> 'child/children' (lit. 'little person').<ref name=NameExoWorlds/>

{{OrbitboxPlanet begin | table_ref = <ref name="Butler2006"/> }} {{OrbitboxPlanet | exoplanet = [[HD 102117 b|b / Leklsullun]] | mass = 0.172 ± 0.020 | period = 20.8133 ± 0.0064 | semimajor = 0.1532 ± 0.0088 | eccentricity = 0.121 ±0.082 }} {{Orbitbox end}}

== See also == * [[List of extrasolar planets]] * [[HARPS spectrograph]] * [[Anglo-Australian Planet Search]]

==References== {{reflist|30em|refs=

<ref name=SIMBAD>{{cite simbad | title=HD 102117 | access-date=2021-01-28 }}</ref>

<ref name=GaiaDR3>{{Cite Gaia DR3|5341673851394297600}}</ref>

<ref name=Houk1979>{{cite book | last1=Houk | first1=Nancy | title=Michigan catalogue of two-dimensional spectral types for the HD stars | location=Ann Arbor, Michigan | publisher=Department of Astronomy, University of Michigan | volume=1 | year=1979 | bibcode=1978mcts.book.....H }}</ref>

<ref name=Anderson_Francis_2012>{{cite XHIP|57291}}</ref>

<ref name=spocs>{{citation | title=SPOCS I | work=Exoplanets | publisher=[[Yale University]] | url=http://exoplanets.astro.yale.edu/science/analysis/spocs.php | access-date=2012-01-31 | archive-date=2012-03-09 | archive-url=https://web.archive.org/web/20120309110733/http://exoplanets.astro.yale.edu/science/analysis/spocs.php | url-status=dead }}</ref>

<ref name=apj22159_1_141>{{citation | last1=Valenti | first1=Jeff A. | last2=Fischer | first2=Debra A. | title=Spectroscopic Properties of Cool Stars (SPOCS). I. 1040 F, G, and K Dwarfs from Keck, Lick, and AAT Planet Search Programs | journal=The Astrophysical Journal Supplement Series | volume=159 | issue=1 | pages=141–166 | date=July 2005 | doi=10.1086/430500 | bibcode=2005ApJS..159..141V | doi-access=free }}</ref>

<ref name="Butler2006">{{cite journal | title=Catalog of Nearby Exoplanets | last1=Butler | first1=R. P. | last2=Wright | first2=J. T. | last3=Marcy | first3=G. W. | last4=Fischer | first4=D. A. | last5=Vogt | first5=S. S. | last6=Tinney | first6=C. G. | last7=Jones | first7=H. R. A. | last8=Carter | first8=B. D. | last9=Johnson | first9=J. A. | last10=McCarthy | first10=C. | last11=Penny | first11=A. J. | display-authors=1 | journal=The Astrophysical Journal | volume=646 | issue=1 | pages=505–522 | date=2006 | arxiv=astro-ph/0607493 | bibcode=2006ApJ...646..505B | doi=10.1086/504701 | s2cid=119067572 }}</ref>

<ref name="Lovis2005">{{cite journal | title=The HARPS search for southern extra-solar planets III. Three Saturn-mass planets around HD 93083, HD 101930 and HD 102117 | last1=Lovis | first1=C. | last2=Mayor | first2=M. | last3=Bouchy | first3=F. | last4=Pepe | first4=F. | last5=Queloz | first5=D. | last6=Santos | first6=N. C. | last7=Udry | first7=S. | last8=Benz | first8=W. | last9=Bertaux | first9=J.-L. | last10=Mordasini | first10=C. | last11=Sivan | first11=J.-P. | display-authors=1 | journal=Astronomy and Astrophysics | volume=437 | issue=3 | pages=1121–1126 | date=2005 | arxiv=astro-ph/0503660 | bibcode=2005A&A...437.1121L | doi=10.1051/0004-6361:20052864 | s2cid=119492030 }}</ref>

<ref name="Tinney2005">{{cite journal | title=Three Low-Mass Planets from the Anglo-Australian Planet Search | last1=Tinney | first1=C. G. | last2=Butler | first2=R. Paul | last3=Marcy | first3=Geoffrey W. | last4=Jones | first4=Hugh R. A. | last5=Penny | first5=Alan J. | last6=McCarthy | first6=Chris | last7=Carter | first7=Brad D. | last8=Fischer | first8=Debra A. | display-authors=1 | journal=The Astrophysical Journal | volume=623 | issue=2 | date=2005 | pages=1171–1179 | bibcode=2005ApJ...623.1171T | doi=10.1086/428661 | citeseerx=10.1.1.491.2941 | s2cid=12515735 }}</ref>

<ref name=NameExoWorlds>{{Cite web | url=http://www.nameexoworlds.iau.org/pitcairn-islands | title=Pitcairn Islands | website=NameExoworlds | language=en | access-date=2019-12-30 }}</ref>

<ref name=houk1975>{{cite journal |last1=Houk |first1=N. |last2=Cowley |first2=A. P. |title=University of Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume I |date=1975 |bibcode=1975mcts.book.....H }}</ref>

}}

== External links == * {{cite web | url=http://media4.obspm.fr/exoplanets/base/etoile.php?nom=HD+102117 | title=HD 102117 | work=Exoplanets | access-date=2009-05-23 | archive-url=https://web.archive.org/web/20120304130302/http://media4.obspm.fr/exoplanets/base/etoile.php?nom=HD+102117 | archive-date=2012-03-04 | url-status=dead }}

{{Sky|11|44|50.4616|-|58|42|13.354|136.9}} {{Stars of Centaurus}} <!-- Properties -->

{{DEFAULTSORT:HD 102117}} [[Category:G-type main-sequence stars]] [[Category:Planetary systems with one confirmed planet]] <!-- Other --> [[Category:Centaurus]] [[Category:Durchmusterung objects|CD-58 04207]] [[Category:Henry Draper Catalogue objects|102117]] [[Category:Hipparcos objects|057291]] [[Category:Stars with proper names|Uklun]]