Editing Alpha Persei

{{Short description|Brightest star in the constellation Perseus}}
{{Starbox begin
| name = α Persei
}}
{{Starbox image
 | image =
{{Location mark
|image = Perseus constellation map.svg
|float = center
|alt =
|label =
|position=  right
|width = 280
|mark = Red circle.svg
|mark_width = 12
|mark_link = α Persei
|x = 550
|y = 420
}}
|caption=Location of α Persei (circled)
}}
{{Starbox observe
 | epoch    = J2000
 | ra       = {{RA|03|24|19.37009}}<ref name=aaa474_2_653/>
 | dec      = {{DEC|+49|51|40.2455}}<ref name=aaa474_2_653/>
 | appmag_v = 1.82<ref name=mnras402_2_1369/>
 | constell = [[Perseus (constellation)|Perseus]]
}}
{{Starbox character
 | class    = F5&nbsp;Ib<ref name=mnras402_2_1369/><ref name=rmaa46_331/>
 | b-v      = +0.483<ref name=clpl4_99/>
 | u-b      = +0.38<ref name=clpl4_99/>
 | variable =
}}
{{Starbox astrometry
 | radial_v = −2.04<ref name=aaa485_1_303/>
 | prop_mo_ra  = +23.75<ref name=aaa474_2_653/>
 | prop_mo_dec = −26.23<ref name=aaa474_2_653/>
 | parallax = 6.44
 | p_error  = 0.17
 | parallax_footnote = <ref name=aaa474_2_653/>
 | absmag_v = −5.1<ref name=rmaa46_331/>
}}
{{Starbox detail
 | mass     = {{val|7.3|0.3}}<ref name=mnras402_2_1369/>
 | radius   = {{val|53.1|1.4}}<ref name="baines"/>
 | luminosity  = {{val|4018|53|fmt=commas}}<ref name=Beng2025/>
 | metal_fe = {{Val|-0.159|0.016}}<ref name=Beng2025/>
 | gravity  = {{val|1.9|0.04}}<ref name=mnras402_2_1369/>
 | age_myr  = 41<ref name=mnras402_2_1369/>
 | rotational_velocity = {{Val|19.0|0.2}}<ref name=Beng2025/>
 | temperature = {{val|6439|80|fmt=commas}}<ref name=Beng2025/>
}}
{{Starbox catalog
 | names=Mirfak, Mirphak, Marfak, Algeneb, Algenib, α&nbsp;Persei, α&nbsp;Per, Alpha&nbsp;Per, 33&nbsp;Persei, [[Bonner Durchmusterung|BD]]+49&nbsp;917, [[Catalog of Components of Double and Multiple Stars|CCDM]]&nbsp;J03243+4951A, [[FK5]]&nbsp;120, [[Boss General Catalogue|GC]]&nbsp;4041, [[Henry Draper Catalogue|HD]]&nbsp;20902, [[Hipparcos catalogue|HIP]]&nbsp;15863, [[Bright Star Catalogue|HR]]&nbsp;1017, [[Index Catalogue of Visual Double Stars|IDS]]&nbsp;03171+4930 A, [[PPM Star Catalogue|PPM]]&nbsp;46127, [[Smithsonian Astrophysical Observatory Star Catalog|SAO]]&nbsp;38787, [[Washington Double Star Catalog|WDS]]&nbsp;J03243+4952A
}}
{{Starbox reference
|Simbad=alf+Per
}}
{{Starbox end}}
'''Alpha Persei''' ([[Latinisation of names|Latinized]] from '''α&nbsp;Persei''', abbreviated '''Alpha&nbsp;Per''', '''α&nbsp;Per'''), formally named '''Mirfak'''<ref name="IAU-CSN">{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt | title=IAU Catalog of Star Names |access-date=28 July 2016}}</ref> (pronounced {{IPAc-en|'|m|3r|f|æ|k}} or {{IPAc-en|'|m|ɪər|f|æ|k}}),<ref>{{Cite Merriam-Webster|Mirfak}}</ref> is the brightest [[star]] in the [[Northern celestial hemisphere|northern]] [[constellation]] of [[Perseus (constellation)|Perseus]], outshining the constellation's best-known star, [[Algol|Algol (β Persei)]]. Alpha Persei has an [[apparent visual magnitude]] of 1.8,<ref name=aaa485_1_303/> and is a [[circumpolar star]] when viewed from mid-northern latitudes.

Alpha Persei lies in the midst of a [[star cluster|cluster of stars]] named as the eponymous [[Alpha Persei Cluster]], or ''Melotte 20'', which is easily visible in [[binoculars]] and includes many of the fainter stars in the constellation.<ref name=kaler/> Determined distance using the trigonometric [[parallax]], places the star {{Convert|510|ly|pc|abbr=off|lk=on}} away.<ref name=aaa474_2_653/>

== Nomenclature ==
''α Persei'' is the star's [[Bayer designation]].

The star also bore the traditional names Mirfak and Algenib, which are [[Arabic]] in origin. The former, meaning 'Elbow' and also written Mirphak, Marfak or Mirzac, comes from the Arabic ''Mirfaq al-Thurayya'', while Algenib, also spelt Algeneb, Elgenab, Gęnib, Chenib or Alchemb, is derived from الجنب ''al-janb'', or الجانب ''al-jānib'', 'the flank' or 'side'.<ref name="allen1899"/><ref name="pa52_3_14"/> and was also the traditional name for [[Gamma Pegasi]].<ref>[https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Pegasus*.html Pegasus]</ref> In 2016, the [[International Astronomical Union]] organized a [[Working Group on Star Names]] (WGSN)<ref name="WGSN">{{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN)|access-date=22 May 2016}}</ref> to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016<ref name="WGSN1">{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/WGSN_bulletin1.pdf | title=Bulletin of the IAU Working Group on Star Names, No. 1 |access-date=28 July 2016}}</ref> included a table of the first two batches of names approved by the WGSN; which included ''Mirfak'' for this star (Gamma Pegasi was given the name ''Algenib'').

''Hinaliʻi'' is the name of the star in [[Native Hawaiian]] astronomy. The name of the star is meant to commemorate a great [[tsunami]] and mark the beginning of the migration of Maui. According to some [[Hawaiian folklore]], Hinaliʻi is the point of separation between the Earth and the sky that happened during the creation of the [[Milky Way]].<ref name="malamalama29_2_8"/>

Assemani alluded to a title on the Borgian globe, ''Mughammid'' (مغمد), or ''Muliammir al Thurayya'' (ملىمرٱلطرى), the Concealer of the [[Pleiades]], which, from its location, may be for this star.<ref name="allen1899"/>

This star, together with [[γ Persei]], [[δ Persei]], [[η Persei]], [[σ Persei]] and [[ψ Persei]], has been called ''the Segment of Perseus''.<ref name="allen1899">{{cite book
 | last=Allen
 | first=R. H.
 | date=1963
 | author-link=Richard Hinckley Allen
 | title=Star Names: Their Lore and Meaning
 | url=https://archive.org/details/starnamestheirlo00alle/page/331
 | access-date=2012-09-04
 | edition=Reprint
 | publisher=Dover Publications
 | location=New York
 | isbn=978-0-486-21079-7
 | page=[https://archive.org/details/starnamestheirlo00alle/page/331 331]
 | url-access=registration
 }}</ref>

In [[Chinese astronomy|Chinese]], {{lang|zh|天船}} ({{lang|zh-Latn|Tiān Chuán}}), meaning ''[[Stomach (Chinese constellation)|Celestial Boat]]'', refers to an [[Asterism (astronomy)|asterism]] consisting of α Persei, γ Persei, δ Persei, η Persei, [[μ Persei]], [[ψ Persei]], [[48 Persei]] and [[HD 27084]]. Consequently, the [[Chinese star names|Chinese name]] for α Persei itself is {{lang|zh|天船三}} ({{lang|zh-Latn|Tiān Chuán sān}}, {{langx|en|the Third Star of Celestial Boat}}).<ref>{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0607/ap060711.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日] {{Webarchive|url=https://web.archive.org/web/20120204114123/http://aeea.nmns.edu.tw/2006/0607/ap060711.html |date=2012-02-04 }}</ref>

== Physical properties ==

[[File:PerseusCC.jpg|thumb|left|upright|Mirfak is the brightest star in the constellation of Perseus (top center).]]

The [[stellar spectrum|spectrum]] of Alpha Persei matches a [[stellar classification]] of F5&nbsp;Ib,<ref name=mnras402_2_1369/> revealing it to be a [[supergiant]] star in the latter stages of its [[stellar evolution|evolution]]. It has a similar spectrum to [[Procyon]] A, though the latter star is much less luminous. This difference is highlighted in their spectral designation under the [[Yerkes spectral classification]], published in 1943, where stars are ranked on luminosity as well as spectral typing. Procyon A is thus F5&nbsp;IV,<ref name=ramanamurthy2007/> a [[subgiant]] star. Since 1943, the spectrum of Alpha Persei has served as one of the stable anchor points by which other stars are classified.<ref name=baas25_1319/>

Alpha Persei has about 7.3<ref name=mnras402_2_1369/> times the [[Sun's mass]] and has expanded to roughly 53 times the [[Solar radius|size of the Sun]].<ref name="baines"/> It is radiating 3,800<ref name=tycho-gaia/> times the [[Solar luminosity|luminosity of the Sun]] from its [[photosphere]] at an [[effective temperature]] of {{Val|6350|fmt=commas|ul=K}},<ref name=mnras402_2_1369/> which creates the yellow-white glow of an [[F-type star]]. 

In the [[Hertzsprung–Russell diagram]], Alpha Persei lies inside the region in which [[Cepheid variable]]s are found.<ref name=apj664_2_1093/> It is thus useful in the study of these stars, which are important [[standard candle]]s.<ref name=kaler/> Despite Mirfak being not a Cepheid, [[Hipparcos]] photometry show a 0.006-[[magnitude (astronomy)|magnitude]] variation with a period of 9.5 days.<ref name=Beng2025/>

== Search for planets ==
Alpha Persei has periodic [[Doppler spectroscopy|radial velocity]] variations, with an amplitude of 70.8 ± 1.6 m/s. These variations are of uncertain origin; a 2012 study considered the possibility of them being caused by an orbiting [[exoplanet]], estimated to have a minimum mass of approximately 6.6 times [[Jupiter mass|that of Jupiter]] and an orbital period of 128 days, but the claimed period may not be stable over 20 years so the exoplanet was considered doubtful. The authors suggested rotational modulation due to surface activity such as starspots as a more likely explanation of the radial velocity variations. In previous publications, periodic radial velocity variations of 87.7 or 77.7 days have been reported, but these have not been confirmed.<ref name=Lee2012/>

A further study, published in 2025, analysing radial velocity observations, found that the period of ~130 days weakened and disappeared during a time, while a 66-day period appeared. The hypothesis of a planet around Mirfak can now be discarded, considering the period changes over time. Variations with periods of 9.8 and 77.7 days, reported in previous studies, have not been detected. The more reasonable explanation to the radial velocity variations is stellar oscillations.<ref name=Beng2025/>

== References ==
{{Reflist|refs=

<ref name=tycho-gaia>{{citation |last1=McDonald |first1=I. |last2=Zijlstra |first2=A. A. |last3=Watson |first3=R. A. |date=2017-10-01 |title=Fundamental parameters and infrared excesses of Tycho-Gaia stars  |journal=Monthly Notices of the Royal Astronomical Society |volume=471 |pages=770–791 |doi=10.1093/mnras/stx1433 |doi-access=free |issn=0035-8711|arxiv=1706.02208 |bibcode=2017MNRAS.471..770M }} [https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=J/MNRAS/471/770&RAJ2000=051.080710 Alpha Persei's database entry] at [[VizieR]].</ref>

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<ref name="baines">{{Citation |last1=Baines |first1=Ellyn K. |last2=Armstrong |first2=J. Thomas |last3=Clark |first3=James H. |last4=Gorney |first4=Jim |last5=Hutter |first5=Donald J. |last6=Jorgensen |first6=Anders M. |last7=Kyte |first7=Casey |last8=Mozurkewich |first8=David |last9=Nisley |first9=Ishara |last10=Sanborn |first10=Jason |last11=Schmitt |first11=Henrique R. |last12=Belle |first12=Gerard T. van |date=October 2021 |title=Angular Diameters and Fundamental Parameters of Forty-four Stars from the Navy Precision Optical Interferometer |journal=The Astronomical Journal |language=en |volume=162 |issue=5 |pages=198 |doi=10.3847/1538-3881/ac2431 |doi-access=free |arxiv=2211.09030 |bibcode=2021AJ....162..198B |issn=1538-3881}}</ref>

<ref name=Lee2012>{{Citation |bibcode=2012A&A...543A..37L |title=Detection of the 128-day radial velocity variations in the supergiant α Persei. Rotational modulations, pulsations, or a planet? |journal=Astronomy and Astrophysics |volume=543 |pages=A37 |last1=Lee |first1=B. -C |last2=Han |first2=I. |last3=Park |first3=M. -G. |last4=Kim |first4=K. -M. |last5=Mkrtichian |first5=D. E. |year=2012 |arxiv=1205.3840 |doi=10.1051/0004-6361/201118539 |s2cid=118482287 }}</ref>

}}
{{Sky|03|24|19.37009|+|49|51|40.2455}}

{{Stars of Perseus}}
{{Portal bar|Astronomy|Stars|Outer space}}

[[Category:F-type supergiants]]
[[Category:Perseus (constellation)]]
[[Category:Alpha Persei Cluster]]
[[Category:Bayer objects|Persei, Alpha]]
[[Category:Durchmusterung objects|BD+49 0917]]
[[Category:Flamsteed objects|Persei, 33]]
[[Category:Henry Draper Catalogue objects|020902]]
[[Category:Hipparcos objects|015863]]
[[Category:Bright Star Catalogue objects|1017]]
[[Category:Stars with proper names|Mirfak]]