View source for Astronomy:HD 104304

{{Short description|Binary star in the constellation Virgo}}
{{Starbox begin}}
{{Starbox observe
 | epoch       = J2000
 | ra          = {{RA|12|00|44.461}}<ref name=GaiaDR2/>
 | dec         = {{DEC|–10|26|46.06}}<ref name=GaiaDR2/>
 | appmag_v    = 5.54<ref name=clpl4_99/>
 | constell    = [[Astronomy:Virgo (constellation)|Virgo]]
}}
{{Starbox character
 | class       = G8&nbsp;IV<ref name=aj132_1_161/> + M4V<ref name=aaa516/>
 | b-v         = +0.76<ref name=clpl4_99/>
 | u-b         = +0.43<ref name=clpl4_99/>
 | variable    = 
}}
{{Starbox astrometry
 | radial_v    = 0.14{{±|0.14}}<ref name=GaiaDR2/>
 | prop_mo_ra  = 82.841
 | prop_mo_dec = −482.807
 | pm_footnote = <ref name=GaiaDR2/>
 | parallax    = 78.7565
 | p_error     = 0.1206
 | parallax_footnote = <ref name=GaiaDR2/>
 | absmag_v    = 5.15{{±|0.009}}<ref name=park2013/>
}}
{{Starbox orbit
 | reference   = <ref name=aaa516/>
 | period      = 48.5
 | eccentricity = 0.29
 | inclination = 35
 | axis_unitless = {{val|10.4|ul=AU}}
}}
{{Starbox detail
 | component1  = A
 | mass        = 0.98<ref name=takeda/>
 | radius      = 1.01<ref name=takeda/>
 | luminosity  = 
 | temperature = {{val|5538|fmt=commas}}<ref name=aj132_1_161/>
 | metal_fe    = 0.18<ref name=mras77_55/>
 | rotational_velocity = 4.5<ref name=aaa493_3_1099/>
 | gravity     = 4.43<ref name=takeda/>
 | age_gyr     = 8.48<ref name=takeda/>
 | component2  = B
 | mass2       = {{val|0.21|0.03|0.02}}<ref name=aaa516/>
}}
{{Starbox catalog
 | names = {{odlist | G=24 G. Virginis | GJ=454 | HD=104304 | BD=-09°3413 | LTT=4476 | HR=4587 | SAO=157041 | HIP=58576 }}<ref name=SIMBAD/>
}}
{{Starbox reference
 | Simbad = HD+104304
}}
{{Starbox end}}

'''HD 104304''' ('''24 G. Virginis''') is a [[Astronomy:Binary star|binary star]] system in the zodiac [[Astronomy:Constellation|constellation]] [[Astronomy:Virgo (constellation)|Virgo]]. It has a combined [[Astronomy:Apparent visual magnitude|apparent visual magnitude]] of 5.54,<ref name=clpl4_99/> making it visible to the unaided eye under suitable viewing conditions. The system is located at a distance of 41&nbsp;[[Astronomy:Light-year|light-year]]s from the [[Astronomy:Sun|Sun]] based on [[Astronomy:Stellar parallax|parallax]] measurements.<ref name=GaiaDR2/> The primary component has a [[Astronomy:Stellar classification|stellar classification]] of G8&nbsp;IV,<ref name=aj132_1_161/> which means that this is a subgiant star that has left the [[Astronomy:Main sequence|main sequence]] and has begun to evolve into a [[Astronomy:Giant star|giant star]]. The secondary is a faint [[Astronomy:Red dwarf|red dwarf]] star with a class of M4V.<ref name=aaa516/>

In 2007, a candidate planet was announced orbiting the primary. This was updated in 2010 when two independent papers announced the discovery of a common proper motion companion [[Astronomy:Red dwarf|red dwarf]].<ref name=aaa516/><ref name=tanner/>  It is believed to have a [[Physics:Mass|mass]] of {{solar mass|0.21|link=y}} and spectral type of M4V although the spectrum has not been directly observed.  The most likely orbit has a [[Astronomy:Orbital period|period]] of 48.5&nbsp;years and an [[Astronomy:Orbital eccentricity|eccentricity]] of 0.29.<ref name=aaa516/><ref name=epe/> Further measurement will be needed to determine whether the star has a planetary companion, but further companions with masses above {{jupiter mass|83|link=y}} and separated by at least 3.9 au can be ruled out.<ref name=aaa516/>

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

<ref name=SIMBAD>{{cite simbad
 | title=HD 104304 | access-date=2021-10-11 }}</ref>

<ref name=GaiaDR2>{{Cite Gaia DR2|3575733210781078016}}</ref>

<ref name=tanner>{{citation | postscript=.
 | title=A High-Contrast Imaging Survey of SIM Lite Planet Search Targets
 | display-authors=1 | last1=Tanner | first1=Angelle M.
 | last2=Gelino | first2=Christopher R. | last3=Law | first3=Nicholas M.
 | journal=Publications of the Astronomical Society of the Pacific
 | volume=122 | issue=896 | pages=1195 | year=2010
 | bibcode=2010PASP..122.1195T | arxiv=1007.4315
 | doi=10.1086/656481 | s2cid=118459054}}</ref>

<ref name=park2013>{{citation | display-authors=1
 | last1=Park | first1=Sunkyung | last2=Kang | first2=Wonseok
 | last3=Lee | first3=Jeong-Eun | last4=Lee | first4=Sang-Gak
 | title=Wilson-Bappu Effect: Extended to Surface Gravity
 | journal=The Astronomical Journal
 | volume=146 | issue=4 | pages=73 | year=2013
 | doi=10.1088/0004-6256/146/4/73 | bibcode=2013AJ....146...73P
 | arxiv=1307.0592 | s2cid=119187733 | postscript=. }}</ref>

<ref name=mras77_55>{{citation
 | last=Hearnshaw | first=J. B.
 | title=The abundances of the elements in the oldest disk stars
 | journal=Memoirs of the Royal Astronomical Society
 | volume=77 | page=55 | date=1972
 | bibcode=1972MmRAS..77...55H }}</ref>

<ref name=aj132_1_161>{{citation
 | 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=[[Astronomy:The Astronomical 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=aaa493_3_1099>{{citation | display-authors=1 | last1=Schröder | first1=C. | last2=Reiners | first2=Ansgar | last3=Schmitt | first3=Jürgen H. M. M. | title=Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo | journal=Astronomy and Astrophysics | volume=493 | issue=3 | pages=1099–1107 | date=January 2009 | doi=10.1051/0004-6361:200810377 | doi-access=free | bibcode=2009A&A...493.1099S | url=http://goedoc.uni-goettingen.de/goescholar/bitstream/handle/1/9690/aa10377-08.pdf?sequence=2 }}{{Dead link|date=September 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

<ref name=clpl4_99>{{citation
 | display-authors=1 | title=UBVRIJKL photometry of the bright stars
 | last1=Johnson | first1=H. L. | last2=Iriarte | first2=B.
 | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z.
 | journal=Communications of the Lunar and Planetary Laboratory
 | volume=4 | issue=99 | pages=99 | date=1966
 | bibcode=1966CoLPL...4...99J }}</ref>

<ref name=epe>{{citation
 | first1=Jean | last1=Schneider
 | title=Star : HD 104304
 | url=http://exoplanet.eu/star.php?st=HD+104304 | archive-url=https://web.archive.org/web/20071113072852/http://exoplanet.eu/star.php?st=HD+104304 | url-status=dead | archive-date=November 13, 2007 | encyclopedia=[[Astronomy:Extrasolar Planets Encyclopaedia|Extrasolar Planets Encyclopaedia]] | access-date=2011-12-21 }}</ref>

<ref name=aaa516>{{citation
 | display-authors=1 | last1=Schnupp | first1=C.
 | last2=Bergfors | first2=C. | last3=Brandner | first3=W.
 | last4=Daemgen | first4=S. | last5=Fischer | first5=D.
 | last6=Marcy | first6=G. | last7=Henning | first7=Th.
 | last8=Hippler | first8=S. | last9=Janson | first9=M.
 | title=Discovery of a stellar companion to the nearby solar-analogue HD 104304
 | journal=Astronomy and Astrophysics
 | volume=516 | page=A21 | date=June 2010
 | doi=10.1051/0004-6361/201014740 | s2cid=54984741
 | bibcode=2010A&A...516A..21S | arxiv=1005.0620 }}</ref>

<ref name=takeda>{{cite journal
 | title=Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog
 | last1=Takeda | first1=Genya | last2=Ford | first2=Eric B.
 | last3=Sills | first3=Alison | last4=Rasio | first4=Frederic A.
 | last5=Fischer | first5=Debra A. | last6=Valenti | first6=Jeff A.
 | display-authors=1 | journal=The Astrophysical Journal Supplement Series
 | volume=168 | issue=2 | pages=297 | year=2007
 | bibcode=2007ApJS..168..297T | arxiv=astro-ph/0607235
 | doi=10.1086/509763 | s2cid=18775378}}</ref>

}}

{{Stars of Virgo}}

{{DEFAULTSORT:HD 104304}}
<!-- Properties -->
[[Category:G-type subgiants]]
[[Category:Solar-type stars|HR, 4587]]
[[Category:M-type main-sequence stars]]
[[Category:Binary stars]]
<!-- Other -->
[[Category:Virgo (constellation)]]
[[Category:Durchmusterung objects]]
[[Category:Gliese and GJ objects|0454]]
[[Category:Gould objects|Virginis, 24]]
[[Category:Henry Draper Catalogue objects|104304]]
[[Category:Hipparcos objects|058576]]
[[Category:Bright Star Catalogue objects|4587]]

{{Sourceattribution|HD 104304}}