{{Short description|Star in the constellation Hydra}} {{Starbox begin | name = HD 82943 }} {{Starbox observe | epoch = J2000 | constell = [[Hydra (constellation)|Hydra]]<ref name=Anderson_Francis_2012/> | ra = {{RA|09|34|50.735}}<ref name=GaiaDR3/> | dec = {{DEC|−12|07|46.37}}<ref name=GaiaDR3/> | appmag_v = 6.54<ref name=Anderson_Francis_2012/> }} {{Starbox character | type = main sequence<ref name=Kennedy_et_al_2013/> | class = {{nowrap|F9 V Fe+0.5}}<ref name=aj132_1_161/> | b-v = 0.623{{±|0.001}}<ref name=Anderson_Francis_2012/> | u-b = | variable = }} {{Starbox astrometry | radial_v = 8.102{{±|0.0003}}<ref name=Soubiran_et_al_2018/> | prop_mo_ra = +1.440 | prop_mo_dec = −174.330 | pm_footnote = <ref name=GaiaDR3/> | parallax = 36.1158 | p_error = 0.0264 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = 4.35<ref name=Anderson_Francis_2012/> }} {{Starbox detail | mass = 1.14{{±|0.01}}<ref name=Bonfanti_et_al_2016/> | radius = 1.17{{±|0.02}}<ref name=Bonfanti_et_al_2016/> | gravity = 4.35{{±|0.01}}<ref name=Bonfanti_et_al_2016/> | luminosity = 1.54{{±|0.02}}<ref name=Bonfanti_et_al_2016/> | temperature = 5,944{{±|18}}<ref name=Bonfanti_et_al_2016/> | metal_fe = 0.265{{±|0.008}}<ref name=Soubiran_et_al_2018/> | rotational_velocity = 1.35{{±|0.5}}<ref name="Butler2006"/> | age_gyr = 3.1{{±|0.4}}<ref name=Bonfanti_et_al_2016/> | rotation = {{val|18.0|ul=days}}<ref name="Mayor2004"/> }} {{Starbox catalog | names = {{odlist | Gould=164 G. Hya | BD=-11 2670 | HD=82943 | HIP=47007 | SAO=155312 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = HD+82943 | NSTED = HD-82943 }} {{Starbox end}}
'''HD 82943''' (164 G. Hydrae) is a [[star]] with a pair of orbiting [[exoplanet]]s in the [[Celestial equator|equatorial]] [[constellation]] of [[Hydra (constellation)|Hydra]]. It has an [[apparent visual magnitude]] of 6.54,<ref name=Anderson_Francis_2012/> which is near the lower limit of visibility to the naked eye. Based on [[stellar parallax|parallax]] measurements, the distance to this system is 90.3 [[light-year]]s.<ref name=GaiaDR3/> It is drifting further away with a heliocentric [[radial velocity]] of 8.1 km/s.<ref name=Soubiran_et_al_2018/> The star shows a high [[proper motion]], traversing the [[celestial sphere]] at an [[angular rate]] of {{val|0.194|u=arcsec yr<sup>−1</sup>}}.<ref name=Luyten1995/>
The [[Astronomical spectroscopy|spectrum]] of HD 82943 presents as an [[F-type main-sequence star]]<ref name=Kennedy_et_al_2013/> with a stellar classification of {{nowrap|F9 V Fe+0.5}}.<ref name=aj132_1_161/> The suffix notation indicates a mild strengthening of iron [[absorption line|lines]] relative to a typical star of its type. Nonetheless, it is considered a metal-rich star,<ref name=Santos_et_al_2000/> having a higher abundance of many elements with masses greater than helium as compared to the Sun. This star is around 3<ref name=Bonfanti_et_al_2016/> billion years old and is spinning with a [[rotation period]] of 18 days.<ref name="Mayor2004"/> It is 14% more [[Solar mass|massive]] and has a 17% larger [[Solar radius|radius]] than the Sun. The star is radiating 154% of the [[luminosity of the Sun]] from its [[photosphere]] at an [[effective temperature]] of 5,944 K.<ref name=Bonfanti_et_al_2016/>
== Planetary system ==
The first exoplanet discovered (designated [[HD 82943 b]]) was announced in 2000 by a team of French astronomers led by [[Michel Mayor]].<ref name="eso0019"/> The exoplanet orbits its parent star at a mean distance of 1.19 [[astronomical unit]]s (AU) and taking approximately 441 [[day]]s to complete the orbit. Nearly a year later, a second exoplanet (designated [[HD 82943 c]]) was announced by the same discoverers of the previous planet.<ref name="eso0114"/> This exoplanet orbits closer than the other, at a mean distance of 0.746 AU and taking 219 days to complete its orbit.<ref name="Lee2006"/> The two known exoplanet appear to have a 2:1 [[Orbital resonance|resonance]] with one another.<ref name="Lee2006"/> Further radial velocity analysis hinted at either long-period stellar activity or presence of a third Jovian exoplanet with an orbital period of 1,075 days.<ref name=Baluev_Beaugé_2014/>
Announced in 2001, HD 82943 was found to contain an unusually high abundance of [[lithium-6]]. Upon reaching a sufficient core temperature, young stars quickly burn through their initial allotment of lithium-6, whereas planets should retain their lithium-6.<ref name="eso0118"/> Thus the simplest and most convincing answer to explain this observation is that one or more planets, or at least planetary material, have fallen into the star sometime after it passed through its early evolutionary stage.
A circumstellar [[debris disk]] was discovered in 2003, based on an [[infrared excess]] detected in the system. The inner edge of this disk orbits at a distance of {{val|67|ul=AU}} from the host star. The distance to the outer edge is poorly constrained.<ref name=Kennedy_et_al_2013/>
{{OrbitboxPlanet begin | table_ref = <ref name="Lee2006"/> }} {{OrbitboxPlanet | exoplanet = [[HD 82943 c|c]] | mass = 14.39 | semimajor = 0.746 | period = 219.3 | eccentricity = 0.359 }} {{OrbitboxPlanet | exoplanet = [[HD 82943 b|b]] | mass = 14.5 | semimajor = 1.19 | period = 441.2 | eccentricity = 0.219 }} {{Orbitbox planet hypothetical | exoplanet = [[HD 82943 d|d]] | mass = 0.29 | semimajor = 2.145 | period = 1078 | eccentricity = – }} {{Orbitbox end}}
== See also == * [[Gliese 876]] * [[HD 169830]] * [[Mu Arae]]
== References == {{Reflist|colwidth=30em|refs=
<ref name=SIMBAD>{{cite simbad | title=HD 82943 | access-date=2024-01-07 }}</ref>
<ref name=GaiaDR3>{{Cite Gaia DR3|2919760965879179136}}</ref>
<ref name=Anderson_Francis_2012>{{cite journal | title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | s2cid=119257644 | doi=10.1134/S1063773712050015 | arxiv=1108.4971 }}</ref>
<ref name=Soubiran_et_al_2018>{{cite journal | title=Gaia Data Release 2. The catalogue of radial velocity standard stars | last1=Soubiran | first1=C. | last2=Jasniewicz | first2=G. | last3=Chemin | first3=L. | last4=Zurbach | first4=C. | last5=Brouillet | first5=N. | last6=Panuzzo | first6=P. | last7=Sartoretti | first7=P. | last8=Katz | first8=D. | last9=Le Campion | first9=J. -F. | last10=Marchal | first10=O. | last11=Hestroffer | first11=D. | last12=Thévenin | first12=F. | last13=Crifo | first13=F. | last14=Udry | first14=S. | last15=Cropper | first15=M. | last16=Seabroke | first16=G. | last17=Viala | first17=Y. | last18=Benson | first18=K. | last19=Blomme | first19=R. | last20=Jean-Antoine | first20=A. | last21=Huckle | first21=H. | last22=Smith | first22=M. | last23=Baker | first23=S. G. | last24=Damerdji | first24=Y. | last25=Dolding | first25=C. | last26=Frémat | first26=Y. | last27=Gosset | first27=E. | last28=Guerrier | first28=A. | last29=Guy | first29=L. P. | last30=Haigron | first30=R. | display-authors=1 | journal=Astronomy and Astrophysics | volume=616 | pages=A7 | year=2018 | bibcode=2018A&A...616A...7S | arxiv=1804.09370 | doi=10.1051/0004-6361/201832795 | s2cid=52952408 }}</ref>
<ref name=Bonfanti_et_al_2016>{{cite journal | title=Age consistency between exoplanet hosts and field stars | display-authors=1 | last1=Bonfanti | first1=A. | last2=Ortolani | first2=S. | last3=Nascimbeni | first3=V. | journal=Astronomy & Astrophysics | year=2016 | volume=585 | id=A5 | pages=14 | arxiv=1511.01744 | bibcode=2016A&A...585A...5B | doi=10.1051/0004-6361/201527297 | s2cid=53971692 }}</ref>
<ref name=Santos_et_al_2000>{{cite journal | title=Chemical analysis of 8 recently discovered extra-solar planet host stars | display-authors=1 | last1=Santos | first1=N. C. | last2=Israelian | first2=G. | last3=Mayor | first3=M. | journal=Astronomy and Astrophysics | volume=363 | pages=228–238 | date=November 2000 | arxiv=astro-ph/0009182 | bibcode=2000A&A...363..228S }}</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. | display-authors=1 | journal=The Astrophysical Journal | date=2006 | volume=646 | issue=1 | pages=505–522 | arxiv=astro-ph/0607493 | bibcode=2006ApJ...646..505B | doi=10.1086/504701 | s2cid=119067572 }}</ref>
<ref name="eso0019">{{cite press release | title=Exoplanets Galore! | date=April 15, 2000 | publisher=[[European Southern Observatory]] | location=Garching, Germany | url=http://www.eso.org/public/news/eso0019/ | access-date=December 30, 2012 }}</ref>
<ref name="eso0114">{{cite press release | title=Exoplanets: The Hunt Continues! | date=April 4, 2001 | publisher=European Southern Observatory | location=Garching, Germany | url=https://www.eso.org/public/news/eso0114/ | access-date=May 3, 2026 }}</ref>
<ref name="eso0118">{{cite press release | title=The Harsh Destiny of a Planet? | date=May 9, 2001 | publisher=[[European Southern Observatory]] | location=Garching, Germany | url=http://www.eso.org/public/news/eso0118/ | access-date=December 30, 2012 }}</ref>
<ref name="Lee2006">{{cite journal | title=On the 2:1 Orbital Resonance in the HD 82943 Planetary System | last1=Lee | first1=Man Hoi | last2=Butler | first2=R. Paul | last3=Fischer | first3=Debra A. | last4=Marcy | first4=Geoffrey W. | last5=Vogt | first5=Steven S. | display-authors=1 | journal=The Astrophysical Journal | date=2006 | volume=641 | issue=2 | pages=1178–1187 | arxiv=astro-ph/0512551 | bibcode=2006ApJ...641.1178L | doi=10.1086/500566 | s2cid=119432579 }}</ref>
<ref name="Mayor2004">{{cite journal | title=The CORALIE survey for southern extra-solar planets XII. Orbital solutions for 16 extra-solar planets discovered with CORALIE | last1=Mayor | first1=M. | last2=Udry | first2=S. | last3=Naef | first3=D. | last4=Pepe | first4=F. | last5=Queloz | first5=D. | last6=Santos | first6=N. C. | last7=Burnet | first7=M. | display-authors=1 | journal=Astronomy and Astrophysics | date=2004 | volume=415 | issue=1 | pages=391–402 | arxiv=astro-ph/0310316 | bibcode=2004A&A...415..391M | doi=10.1051/0004-6361:20034250 | s2cid=5233877 }}</ref>
<ref name=aj132_1_161>{{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 | arxiv=astro-ph/0603770 | bibcode=2006AJ....132..161G | s2cid=119476992 }}</ref>
<ref name=Baluev_Beaugé_2014>{{Cite journal | title=Possible solution to the riddle of HD 82943 multiplanet system: The three-planet resonance 1:2:5? | last1=Baluev | first1=Roman V. | last2=Beaugé | first2=Cristian | journal=Monthly Notices of the Royal Astronomical Society | volume=439 | pages=673–689 | year=2014 | issue=1 | arxiv=1310.7101 | doi=10.1093/mnras/stt2486 | doi-access=free | bibcode=2014MNRAS.439..673B }}</ref>
<ref name=Kennedy_et_al_2013>{{cite journal | title=Star-planet-debris disc alignment in the HD 82943 system: is planetary system coplanarity actually the norm | display-authors=1 | last1=Kennedy | first1=G. M. | last2=Wyatt | first2=M. C. | last3=Bryden | first3=G. | last4=Wittenmyer | first4=R. | last5=Sibthorpe | first5=B. | journal=Monthly Notices of the Royal Astronomical Society | volume=436 | issue=1 | pages=898–903 | date=November 2013 | doi=10.1093/mnras/stt1657 | doi-access=free | arxiv=1309.1466 | bibcode=2013MNRAS.436..898K }}</ref>
<ref name=Luyten1995>{{cite journal | title=NLTT Catalogue (Luyten, 1979) | last=Luyten | first=W. J. | journal=VizieR Online Data Catalog | date=June 1995 | bibcode=1995yCat.1098....0L }}</ref>
}}
== External links == * {{Cite APOD |title=HD 82943: Planet Swallower |access-date=2008-07-15 |date=18 May 2001 }} * {{cite encyclopedia |url=http://exoplanet.eu/star.php?st=HD+82943 |archive-url=https://web.archive.org/web/20071106060202/http://exoplanet.eu/star.php?st=HD+82943 |url-status=dead |archive-date=November 6, 2007 |encyclopedia=[[Extrasolar Planets Encyclopaedia]] |title=Notes for star HD 82943 |access-date=2008-07-15 }} * {{cite web |url=http://www.eso.org/public/outreach/press-rel/pr-2001/pr-10-01.html |title=The Harsh Destiny of a Planet? |access-date=2008-07-15 |work=[[European Southern Observatory]] |date=2001-05-09 |url-status=dead |archive-url=https://web.archive.org/web/20080507074309/http://www.eso.org/public/outreach/press-rel/pr-2001/pr-10-01.html |archive-date=2008-05-07 }} * [http://www.lpl.arizona.edu/~rory/research/xsp/dynamics/ Extrasolar Planet Interactions] {{Webarchive|url=https://web.archive.org/web/20160505160348/http://www.lpl.arizona.edu/~rory/research/xsp/dynamics/ |date=2016-05-05 }} by Rory Barnes & Richard Greenberg, Lunar and Planetary Lab, University of Arizona
{{Sky|09|34|50.736|-|12|07|46.365|89.56}} {{Stars of Hydra}}
<!-- Properties --> [[Category:F-type main-sequence stars]] [[Category:Planetary systems with two confirmed planets]] [[Category:Circumstellar disks]] <!-- Location/catalogues --> [[Category:Hydra (constellation)]] [[Category:Durchmusterung objects]] [[Category:Henry Draper Catalogue objects|082943]] [[Category:Hipparcos objects|047007]]