HD 72659

{{short description|Star in the constellation of Hydra}} {{Starbox begin}} {{Starbox observe | epoch = J2000.0 | constell = [[Hydra (constellation)|Hydra]]<ref name=Anderson2012/> | ra = {{RA|08|34|03.18984}}<ref name=GaiaDR3/> | dec = {{DEC|-01|34|05.5822}}<ref name=GaiaDR3/> | appmag_v = 7.46<ref name=Anderson2012/> }} {{Starbox character | type = [[subgiant]]<ref name=GaiaDR3/> | class = G2V<ref name=Houk1999/> | b-v = {{Val|+0.612|0.015}}<ref name=Anderson2012/> | u-b = | variable = }} {{Starbox astrometry | radial_v = {{val|-18.203|0.024|0.029}}<ref name=Ruggieri2025/> | prop_mo_ra = {{val|-112.313|(26)}} | prop_mo_dec = {{val|-96.386|(18)}} | pm_footnote = <ref name=GaiaDR3/> | parallax = 19.2582 | p_error = 0.0271 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = 3.98<ref name=Anderson2012/> }} {{Starbox detail | source = <ref name=Ruggieri2025/> | mass = {{val|1.033|0.025}} | radius = {{val|1.36|0.06}} | luminosity = {{val|2.16|0.01}}<ref name="Bonfanti2015"/> | gravity = {{val|4.19|0.02}}<ref name="Bonfanti2015"/> | temperature = {{val|5929|61|fmt=commas}} | metal_fe = {{Val|−0.02|0.06}} | rotation = | rotational_velocity = {{val|1.6|0.9}} | age_gyr = {{val|8|1}} }} {{Starbox catalog | names = {{odlist | BD=−01°2075 | HD=72659 | HIP=42030 | SAO=136045|Gaia DR2=3073443760538892032|2MASS=J08340320-0134056}}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = HD+72659 | NSTED = HD-72659 }} {{Starbox end}}

'''HD 72659''' is a [[star]] in the [[celestial equator|equatorial]] [[constellation]] of [[Hydra (constellation)|Hydra]]. With an [[apparent visual magnitude]] of 7.46,<ref name=Anderson2012/> its yellow-hued star is too faint to be viewed with the naked eye. [[Stellar parallax|Parallax]] measurements provide a distance estimate of 169.4 [[light year]]s from the [[Sun]], and it has an [[absolute magnitude]] of 3.98.<ref name=Anderson2012/> The star is drifting closer with a [[radial velocity]] of −18.2 km/s.<ref name=Ruggieri2025/>

This is a Sun-like [[main sequence]] star with a [[stellar classification]] of G2V,<ref name=Houk1999/> indicating that it is generating energy through [[stellar core|core]] [[hydrogen fusion]]. It is older than the Sun with an age of about seven billion years,<ref name="Bonfanti2015"/> and is spinning with a [[projected rotational velocity]] of 5.1 km/s.<ref name=Earle2017/> The star has 7% greater mass than the Sun and a 38% larger radius. It is radiating more than double the [[Sun's luminosity]] from its [[photosphere]] at an [[effective temperature]] of 5,956 K.<ref name="Bonfanti2015"/> The [[metallicity]] of the [[stellar atmosphere]] is similar to the Sun.<ref name=Anderson2012/>

==Planetary system== An [[extrasolar planet]] was discovered orbiting this star in 2003 via the [[Doppler spectroscopy|Doppler method]].<ref name="Butler2003"/> This is a [[superjovian planet]] with an eccentric orbit, completing a lap around its host star every {{Convert|3630|days|years|disp=out|abbr=off}}.<ref name="Butler2006"/> In 2022, the inclination and true mass of HD 72659 b were measured via [[astrometry]], along with the detection of a second substellar companion, likely a [[brown dwarf]].<ref name="Feng2022"/> The orbit of the brown dwarf lies in the so-called [[brown dwarf desert]], regions with a deficit of brown dwarfs. The host star is very old and thus HD 72659 b and c can not be [[direct imaging|directly imaged]], even with the most modern equipment such as the [[James Webb Space Telescope]]. The moderate eccentricity of planet b may be the result of [[Kozai mechanism|Kozai-Lidov oscillations]].<ref name=Ruggieri2025/>

{{OrbitboxPlanet begin | table_ref = <ref name=Ruggieri2025/> | period_unit = year }} {{OrbitboxPlanet | exoplanet = [[HD 72659 b|b]] | mass = {{val|3.0|2.6|0.1}}<ref name="Feng2022"/> | period = {{val|9.72|0.03}} | semimajor = {{val|4.607|0.039}} | eccentricity = {{val|0.239|0.001}} | inclination = {{val|78|40}}<ref name="Feng2022"/> }} {{OrbitboxPlanet | exoplanet = c | mass = {{val|19.4|0.8|0.5}} | period = {{val|97.1|3.4|2.5}} | semimajor = {{val|21.5|0.5|0.4}} | eccentricity = {{val|0.114|0.002|0.003}} | inclination = {{val|40|2}} }} {{Orbitbox end}}

== See also == * [[HD 73256]] * [[List of extrasolar planets]]

== References == {{Reflist|refs=

<ref name=SIMBAD>{{cite simbad | title=HD 72659 | access-date=2020-01-24 }}</ref>

<ref name=Ruggieri2025>{{cite journal|last1=Ruggieri |first1=A. |last2=Sozzetti |first2=A. |last3=Desidera |first3=S. |last4=Mesa |first4=D. |last5=Gratton |first5=R. |last6=Marzari |first6=F. |last7=Bonavita |first7=M. |last8=Biazzo |first8=K. |last9=D'Orazi |first9=V. |last10=Ginski |first10=C. |last11=Meyer |first11=M. |last12=Malavolta |first12=L. |last13=Pinamonti |first13=M. |last14=Barbato |first14=D. |last15=Lazzoni |first15=C. |last16=Lanza |first16=A. F. |last17=Mancini |first17=L. |last18=Naponiello |first18=L. |last19=Nardiello |first19=D. |last20=Zingales |first20=T. |last21=Rainer |first21=M. |last22=Scandariato |first22=G. |last23=Giacobbe |first23=P. |last24=Cosentino |first24=R. |last25=Fiorenzano |first25=A. |last26=Claudi |first26=R. |title=The GAPS programme at TNG LXVIII. Characterization of the outer substellar companion around HD 72659 with a multitechnique approach |journal=Monthly Notices of the Royal Astronomical Society |date=2025 |volume=542 |issue=2 |pages=1233–1247 |doi=10.1093/mnras/staf1251 |doi-access=free |arxiv=2507.19063}}</ref>

<ref name=Houk1999>{{cite journal | title=Michigan catalogue of two-dimensional spectral types for the HD Stars | last1=Houk | first1=N. | last2=Swift | first2=C. | journal=Michigan Spectral Survey | volume=5 | year=1999 | bibcode=1999MSS...C05....0H }}</ref>

<ref name="Bonfanti2015">{{cite journal | title=Revising the ages of planet-hosting stars | last1=Bonfanti | first1=A. | last2=Ortolani | first2=S. | last3=Piotto | first3=G. | last4=Nascimbeni | first4=V. | display-authors=1 | journal=Astronomy and Astrophysics | year=2015 | volume=575 | at=A18 | arxiv=1411.4302 | bibcode=2015A&A...575A..18B | doi=10.1051/0004-6361/201424951 | s2cid=54555839 }}</ref>

<ref name="Butler2003">{{cite journal | title=Seven New Keck Planets Orbiting G and K Dwarfs | last1=Butler | first1=R. Paul | last2=Marcy | first2=Geoffrey W. | last3=Vogt | first3=Steven S. | last4=Fischer | first4=Debra A. | last5=Henry | first5=Gregory W. | last6=Laughlin | first6=Gregory | last7=Wright | first7=Jason T. | display-authors=1 | journal=The Astrophysical Journal | date=2003 | volume=582 | issue=1 | pages=455–466 | doi=10.1086/344570 | bibcode=2003ApJ...582..455B | citeseerx=10.1.1.7.6988 | s2cid=17608922 }}</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 | volume=646 | issue=1 | pages=505–522 | date=2006 | doi=10.1086/504701 | bibcode=2006ApJ...646..505B | arxiv=astro-ph/0607493 | hdl=2299/1103 | s2cid=119067572 }}</ref>

<ref name=Earle2017>{{cite journal | title=Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants | last1=Luck | first1=R. Earle | journal=The Astronomical Journal | volume=153 | issue=1 | id=21 | pages=19 | date=January 2017 | bibcode=2017AJ....153...21L | arxiv=1611.02897 | doi=10.3847/1538-3881/153/1/21 | s2cid=119511744 | doi-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>

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== External links ==

[[Category:G-type main-sequence stars]] [[Category:Planetary systems with two confirmed planets]] [[Category:Hydra (constellation)]] [[Category:Durchmusterung objects|BD-01 2075]] [[Category:Henry Draper Catalogue objects|072659]] [[Category:Hipparcos objects|042030]]