HR 4458

{{Short description|Binary star system in the constellation Hydra}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=Hydra constellation map.svg|alt=|float=center|width=320 |label=|position=right |mark=Red circle.svg|mark_width=8|mark_link=20 Crateris |x=438|y=476 }} | caption = Location of 20 Crateris (circled in red) }} {{Starbox observe 2s | constell = [[Hydra (constellation)|Hydra]]<ref name=constellation/> | epoch = J2000 | component1 = A | ra1 = {{RA|11|34|29.48644}}<ref name=GaiaDR3/> | dec1 = {{DEC|-32|49|52.8228}}<ref name=GaiaDR3/> | appmag_v1 = 5.97<ref name="aaa34"/> | component2 = B | ra2 = {{RA|11|34|30.47776}}<ref name=dr3b/> | dec2 = {{DEC|-32|50|02.4048}}<ref name=dr3b/> | appmag_v2 = 15<ref name=holberg2002/> }} {{Starbox character | component1 = A | type = [[main sequence]]<ref name=GaiaDR3/> | class = K0 V<ref name=aj132_1_161/> | b-v = +0.80<ref name="aaa34"/> | u-b = +0.325<ref name="aaa34"/> | component2 = B | type2 = [[white dwarf]]<ref name=holberg2002/> | class2 = DC8<ref name=mnras435_3_2077/> }} {{Starbox astrometry | component1 = A | radial_v = {{val|-22.09|0.12}}<ref name=GaiaDR3/> | prop_mo_ra = −670.230 | prop_mo_dec = +822.399 | pm_footnote = <ref name=GaiaDR3/> | parallax = 104.6133 | p_error = 0.0277 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = 6.05<ref name=Holmberg2009/> | component2 = B | radial_v2 = | prop_mo_ra2 = –701.802 | prop_mo_dec2 = +828.928 | pm_footnote2 = <ref name=dr3b/> | parallax2 = 104.6570 | p_error2 = 0.0267 | parallax_footnote2 = <ref name=dr3b/> | absmag_v2 = 15<ref name=reid1995/> }} {{starbox orbit | reference = <ref name=An2025/> | period = {{Val|1400|600|510|fmt=commas}} | axis_unitless = {{Val|142|38|37|ul=au}} | eccentricity = {{Val|0.28|0.57|0.22}} | inclination = {{Val|83.4|2.1|7.1}} }} {{Starbox detail | component1=HR 4458 A | mass = {{Val|0.900|0.044|0.045}}<ref name=An2025/> | radius = 0.84<ref name="ajss183"/> | temperature = 5,241<ref name="apj756_1_46"/> | gravity = 4.59<ref name="apj756_1_46"/> | metal_fe = −0.37<ref name="apj756_1_46"/> | rotational_velocity = 6.79<ref name=aaa520_A79/> | luminosity_bolometric = 0.368<ref name=aa555_A11/> | age_gyr = 4.6–5.8<ref name="apj687"/> | component2=HR 4458 B | mass2 = {{Val|0.554|0.022}}<ref name=An2025/> | radius2 = | temperature2 = 5,000<ref name=bagnulo2021/> | gravity2 = 8.12<ref name=hollands2018/> | metal_fe2 = | rotational_velocity2 = | luminosity_bolometric2 = 0.000088<ref name=holberg2016/> | age_gyr2 = 5.69<ref name=bagnulo2021/>{{efn|name=cooling}} }} {{Starbox catalog | names = {{odlist | F=20 Crt | Gould=289 G. Hya | GJ=432 | CD=−32°8179 | HD=100623 | HIP=56452 | HR=4458 | SAO=202583 | PLX=2678.00 | LHS=308 | LTT=4280 }}<ref name=SIMBAD/> | component2=B | names2={{odlist | name=[[Van Biesbroeck's star catalog|VB]] 4 | WD=1132−325}} }} {{Starbox reference | Simbad=HD+100623 |sn=A | Simbad2=HD+100623B |sn2=B | ARICNS=00888 }} {{Starbox end}}

'''HR 4458''' ('''HD 100623''') is a [[binary star]] [[system]] 31.18 [[light-year]]s away in the [[celestial equator|equatorial]] [[constellation]] of [[Hydra (constellation)|Hydra]]. It has the [[Flamsteed designation]] '''20 Crateris'''<ref name=Wagman1987/> and the [[Gould designation]] '''289 G. Hydrae''';<ref name=Gould1879/> the former refers to the constellation [[Crater (constellation)|Crater]], since Flamsteed numbered the stars of Crater and the central portion of Hydra as a separate constellation from the other parts of Hydra.<ref name=Wagman1987/> This object is visible to the naked eye as a dim, orange-hued star with an [[apparent visual magnitude]] of 5.97.<ref name="aaa34"/> It is moving closer to the Earth with a heliocentric [[radial velocity]] of {{val|−22|u=km/s}}.<ref name="apjss141"/>

The primary component is a [[K-type main-sequence star]] with a [[stellar classification]] of K0 V.<ref name=aj132_1_161/> It is around five billion years old<ref name="apj687"/> with 90% of the [[Sun's mass]]<ref name=An2025/> and 84% of the [[Sun's radius]].<ref name="ajss183"/> The star is radiating 37% of the [[Sun's luminosity]]<ref name=aa555_A11/> from its [[photosphere]] at an [[effective temperature]] of 5,241 K.<ref name="apj756_1_46"/> It has been examined for the presence of an [[infrared excess]], but none was detected.<ref name=aa555_A11/>

The secondary, designated VB 4, is a 15th-magnitude [[white dwarf]] of class DC8 sharing [[common proper motion]] with the primary.<ref name=mnras435_3_2077/><ref name=Rodriguez2015/> The orbital period of the pair is of 1,400 years, albeit with large uncertainty.<ref name=An2025/>

==Notes== {{notelist|refs=

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==References== {{Reflist|refs=

<ref name=SIMBAD>{{cite simbad | title=HD 100623 | access-date=May 6, 2019 }}</ref>

<ref name=constellation>{{cite constellation|HR 4458}}</ref>

<ref name=reid1995>{{cite journal |bibcode=1995AJ....110.1838R |title=The Palomar/MSU Nearby-Star Spectroscopic Survey. I. The Northern M Dwarfs -Bandstrengths and Kinematics |last1=Reid |first1=I. Neill |last2=Hawley |first2=Suzanne L. |last3=Gizis |first3=John E. |journal=The Astronomical Journal |date=1995 |volume=110 |page=1838 |doi=10.1086/117655 }}</ref>

<ref name=Gould1879>{{cite journal | url=http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=V%2F135%2Fcatalog | last=Gould | first=Benjamin Apthorp | date=1879 | title=Uranometria Argentina catalog of bright southern stars | journal=Resultados del Observatorio Nacional Argentino en Cordoba | volume=1 | publication-place=Buenos Aires | bibcode=1879RNAO....1.....G | access-date=2012-05-08 }}</ref>

<ref name=Wagman1987>{{cite journal | last=Wagman | first=M. | title=Flamsteed's Missing Stars | journal=Journal for the History of Astronomy | issue=3 | volume=18 | page=215 | bibcode=1987JHA....18..209W |date=August 1987 | doi=10.1177/002182868701800305| s2cid=118445625 }}</ref>

<ref name=hollands2018>{{cite journal |bibcode=2018MNRAS.480.3942H |title=The Gaia 20 pc white dwarf sample |last1=Hollands |first1=M. A. |last2=Tremblay |first2=P. -E. |last3=Gänsicke |first3=B. T. |last4=Gentile-Fusillo |first4=N. P. |last5=Toonen |first5=S. |journal=Monthly Notices of the Royal Astronomical Society |date=2018 |volume=480 |issue=3 |page=3942 |doi=10.1093/mnras/sty2057 |doi-access=free |arxiv=1805.12590 }}</ref>

<ref name=Holmberg2009>{{cite journal | display-authors=1 | last1=Holmberg | first1=J. | last2=Nordström | first2=B. | last3=Andersen | first3=J. | title=The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics | volume=501 | issue=3 |date=July 2009 | pages=941–947 | journal=Astronomy and Astrophysics | doi=10.1051/0004-6361/200811191 | bibcode=2009A&A...501..941H | arxiv=0811.3982 | s2cid=118577511 }}</ref>

<ref name=bagnulo2021>{{cite journal |bibcode=2021MNRAS.507.5902B |title=New insight into the magnetism of degenerate stars from the analysis of a volume-limited sample of white dwarfs |last1=Bagnulo |first1=S. |last2=Landstreet |first2=J. D. |journal=Monthly Notices of the Royal Astronomical Society |date=2021 |volume=507 |issue=4 |page=5902 |doi=10.1093/mnras/stab2046 |doi-access=free |arxiv=2106.11109 }}</ref>

<ref name=holberg2002>{{cite journal | last1=Holberg | first1=J. B. | last2=Oswalt | first2=Terry D. | last3=Sion | first3=E. M. | title= A Determination of the Local Density of White Dwarf Stars | journal=The Astrophysical Journal | year=2002 | volume=571 | issue=1 | pages=512–518 | bibcode=2002ApJ...571..512H | doi=10.1086/339842 | doi-access=free| arxiv=astro-ph/0102120 }}</ref>

<ref name=holberg2016>{{cite journal |bibcode=2016MNRAS.462.2295H |title=The 25 parsec local white dwarf population |last1=Holberg |first1=J. B. |last2=Oswalt |first2=T. D. |last3=Sion |first3=E. M. |last4=McCook |first4=G. P. |journal=Monthly Notices of the Royal Astronomical Society |date=2016 |volume=462 |issue=3 |page=2295 |doi=10.1093/mnras/stw1357 |doi-access=free |arxiv=1606.01236 }}</ref>

<ref name="ajss183">{{cite journal | last1=Johnson | first1=H. M. | last2=Wright | first2=C. D. | title=Predicted infrared brightness of stars within 25 parsecs of the sun | journal=Astrophysical Journal Supplement Series | year=1983 | volume=53 | issue=2 | pages=643–711 | bibcode=1983ApJS...53..643J | doi=10.1086/190905 | doi-access=free}}</ref>

<ref name=An2025>{{cite journal |last1=An |first1=Qier |last2=Brandt |first2=Timothy D. |last3=Brandt |first3=G. Mirek |last4=Venner |first4=Alexander |date=October 2025 |title=Orbits and Masses for 156 Companions from Combined Astrometry and Radial Velocities, and a Validation of Gaia Non-single-star Solutions |bibcode=2025ApJS..280...61A |journal=The Astrophysical Journal Supplement Series |language=en |volume=280 |issue=2 |pages=61 |doi=10.3847/1538-4365/adfa99 |doi-access=free |arxiv=2508.08374 |issn=0067-0049}}</ref>

<ref name="apj687">{{cite journal | last1=Mamajek | first1=Eric E. | last2=Hillenbrand | first2=Lynne A. | title=Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics | journal=The Astrophysical Journal | volume=687 | issue=2 | pages=1264–1293 |date=November 2008 | doi=10.1086/591785 | bibcode=2008ApJ...687.1264M |arxiv = 0807.1686 | s2cid=27151456 }}</ref>

<ref name=aj132_1_161>{{cite journal | display-authors=1 | 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. | title=Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample | journal=[[The Astronomical Journal]] | volume=132 | issue=1 | pages=161–70 | date=2006 | doi=10.1086/504637 | bibcode=2006AJ....132..161G | arxiv=astro-ph/0603770 | s2cid=119476992 }}</ref>

<ref name="apjss141">{{cite journal | display-authors=1 | last1=Nidever | first1=David L. | last2=Marcy | first2=Geoffrey W. | last3=Butler | first3=R. Paul | last4=Fischer | first4=Debra A. | last5=Vogt | first5=Steven S. | title=Radial Velocities for 889 Late-Type Stars | journal=The Astrophysical Journal Supplement Series | volume=141 | issue=2 | pages=503–522 | date=August 2002 | doi=10.1086/340570 | bibcode=2002ApJS..141..503N | arxiv=astro-ph/0112477 | s2cid=51814894 }}</ref>

<ref name="apj756_1_46">{{cite journal | display-authors=1 | last1=Ramírez | first1=I. | last2=Fish | first2=J. R. | last3=Lambert | first3=D. L. | last4=Allende Prieto | first4=C. | title=Lithium Abundances in nearby FGK Dwarf and Subgiant Stars: Internal Destruction, Galactic Chemical Evolution, and Exoplanets | journal=The Astrophysical Journal | volume=756 | issue=1 | page=46 | date=September 2012 | doi=10.1088/0004-637X/756/1/46 | bibcode=2012ApJ...756...46R | arxiv=1207.0499 | s2cid=119199829 }}</ref>

<ref name=aaa520_A79>{{cite journal | display-authors=1 | last1=Martínez-Arnáiz | first1=R. | last2=Maldonado | first2=J. | last3=Montes | first3=D. | last4=Eiroa | first4=C. | last5=Montesinos | first5=B. | title=Chromospheric activity and rotation of FGK stars in the solar vicinity. An estimation of the radial velocity jitter | journal=Astronomy and Astrophysics | volume=520 | page=A79 | date=September 2010 | doi=10.1051/0004-6361/200913725 | bibcode=2010A&A...520A..79M | arxiv=1002.4391 | s2cid=43455849 }}</ref>

<ref name="aaa34">{{cite journal | author=Mermilliod, J.-C. | title=Compilation of Eggen's UBV data, transformed to UBV (unpublished) | journal=Catalogue of Eggen's UBV Data | date=1986 | bibcode=1986EgUBV........0M }}</ref>

<ref name=mnras435_3_2077>{{cite journal | display-authors=1 | last1=Holberg | first1=J. B. | last2=Oswalt | first2=T. D. | last3=Sion | first3=E. M. | last4=Barstow | first4=M. A. | last5=Burleigh | first5=M. R. | title=Where are all the Sirius-like binary systems? | journal=Monthly Notices of the Royal Astronomical Society | volume=435 | issue=3 | pages=2077–2091 |date=November 2013 | doi=10.1093/mnras/stt1433 | doi-access=free | bibcode=2013MNRAS.435.2077H | arxiv=1307.8047 }}</ref>

<ref name=aa555_A11>{{cite journal | display-authors=1 | last1=Eiroa | first1=C. | last2=Marshall | first2=J. P. | last3=Mora | first3=A. | last4=Montesinos | first4=B. | last5=Absil | first5=O. | last6=Augereau | first6=J. Ch. | last7=Bayo | first7=A. | last8=Bryden | first8=G. | last9=Danchi | first9=W. | last10=del Burgo | first10=C. | last11=Ertel | first11=S. | last12=Fridlund | first12=M. | last13=Heras | first13=A. M. | last14=Krivov | first14=A. V. | last15=Launhardt | first15=R. | last16=Liseau | first16=R. | last17=Löhne | first17=T. | last18=Maldonado | first18=J. | last19=Pilbratt | first19=G. L. | last20=Roberge | first20=A. | last21=Rodmann | first21=J. | last22=Sanz-Forcada | first22=J. | last23=Solano | first23=E. | last24=Stapelfeldt | first24=K. | last25=Thébault | first25=P. | last26=Wolf | first26=S. | last27=Ardila | first27=D. | last28=Arévalo | first28=M. | last29=Beichmann | first29=C. | last30=Faramaz | first30=V. | last31=González-García | first31=B. M. | last32=Gutiérrez | first32=R. | last33=Lebreton | first33=J. | last34=Martínez-Arnáiz | first34=R. | last35=Meeus | first35=G. | last36=Montes | first36=D. | last37=Olofsson | first37=G. | last38=Su | first38=K. Y. L. | last39=White | first39=G. J. | last40=Barrado | first40=D. | last41=Fukagawa | first41=M. | last42=Grün | first42=E. | last43=Kamp | first43=I. | last44=Lorente | first44=R. | last45=Morbidelli | first45=A. | last46=Müller | first46=S. | last47=Mutschke | first47=H. | last48=Nakagawa | first48=T. | last49=Ribas | first49=I. | last50=Walker | first50=H. | title=DUst around NEarby Stars. The survey observational results | journal=Astronomy & Astrophysics | volume=555 | page=A11 | date=July 2013 | doi=10.1051/0004-6361/201321050 | bibcode=2013A&A...555A..11E | arxiv=1305.0155 | s2cid=377244 }}</ref>

<ref name=Rodriguez2015>{{cite journal | display-authors=1 | last1=Rodriguez | first1=David R. | last2=Duchêne | first2=Gaspard | last3=Tom | first3=Henry | last4=Kennedy | first4=Grant M. | last5=Matthews | first5=Brenda | last6=Greaves | first6=Jane | last7=Butner | first7=Harold | title=Stellar multiplicity and debris discs: An unbiased sample | journal=Monthly Notices of the Royal Astronomical Society | volume=449 | issue=3 | pages=3160 | year=2015 | bibcode=2015MNRAS.449.3160R | doi=10.1093/mnras/stv483 | arxiv=1503.01320 | doi-access=free }}</ref>

}}

==External links== * {{cite web | url =http://www.solstation.com/stars/hr4458ab.htm | title =CD-32 8179 / HR 4458 AB | publisher =SolStation | access-date =2007-06-06 | archive-url =https://web.archive.org/web/20121013003737/http://www.solstation.com/stars/hr4458ab.htm | archive-date =2012-10-13 | url-status =dead }}

[[Category:K-type main-sequence stars]] [[Category:Solar analogs|HR, 4458]] [[Category:White dwarfs]] [[Category:Binary stars]] [[Category:Hydra (constellation)]] [[Category:Durchmusterung objects|CD-32 08179]] [[Category:Flamsteed objects|Crateris, 20]] [[Category:Gliese and GJ objects|0432]] [[Category:Gould objects|Hydrae, 289]] [[Category:Henry Draper Catalogue objects|100623]] [[Category:Hipparcos objects|056452]] [[Category:Bright Star Catalogue objects|4458]]