# 45 Herculis

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> Source: https://en.wikipedia.org/wiki/45_Herculis
> Source revision: 1328173174
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{{Short description|Star in the constellation Hercules}}
{{Starbox begin}}
{{Starbox image
| image = 250px
| caption = An [ultraviolet band](/source/Photometric_system) [light curve](/source/light_curve) for V776 Herculis, adapted from Burke and Barr (1981)<ref name="Burke"/>
}}
{{Starbox observe
 | epoch       = J2000
 | constell    = [Hercules](/source/Hercules_(constellation))
 | ra          = {{RA|16|47|46.41942}}<ref name=GaiaDR2/>
 | dec         = {{DEC|+05|14|48.2789}}<ref name=GaiaDR2/>
 | appmag_v    = 5.22<ref name=Ducati/>
}}
{{Starbox character
 | type        = [main sequence](/source/main_sequence) or [subgiant](/source/subgiant)<ref name=Kochukhov/>
 | class       = {{nowrap|A1 Vp Si}}<ref name=abt1995/> or {{nowrap|B9p Cr}}<ref name=Cowley1969/>
 | b-v         = −0.025<ref name=EgUBV/>
 | u-b         = +0.005<ref name=EgUBV/>
 | variable    = [α<sup>2</sup> CVn](/source/Alpha2_Canum_Venaticorum_variable)<ref name=Samus2017/>
}}
{{Starbox astrometry
 | radial_v    = {{Val|-13.13|0.09}}<ref name=Kochukhov/>
 | prop_mo_ra  = −18.802<ref name=GaiaDR2/>
 | prop_mo_dec = −38.735<ref name=GaiaDR2/>
 | parallax    = 8.1955
 | p_error     = 0.2169
 | parallax_footnote = <ref name=GaiaDR2/>
 | absmag_v    = −0.18<ref name=Anderson2012/>
}}
{{Starbox orbit
 | reference = <ref name=Kochukhov/>
 | period_unitless = {{val|99.51|0.10|u=d}}
 | epoch = {{val|fmt=none|2456702.6|2.1}}
 | k1 = {{val|4.75|0.12}}
 | eccentricity = {{val|0.445|0.020}}
 | periarg_primary = {{val|167.1|4.2}}
}}
{{Starbox detail
 | mass        = {{Val|2.85|0.11}}<ref name=Martin2017/>
 | radius      = 4.3<ref name=shulyak2014/>
 | temperature = 9,400<ref name=Kochukhov/>
 | luminosity  = 129.7<ref name=Kochukhov/>
 | gravity     = 3.55<ref name=Wolff1967/>
 | metal_fe    = 0.10<ref name=Wolff1967/>
 | rotational_velocity = 35.5<ref name=Royer2002/>
 | age_myr     = 351–469<ref name=Kochukhov/>
 | rotation    = {{val|fmt=none|4.116476|0.000022|u=d}}<ref name=Kochukhov/>
}}
{{Starbox catalog
 | names={{odlist | B=l&nbsp;Her | F=45&nbsp;Her | V=V776&nbsp;Herculis | BD=+05°3272 | HD=151525 | HIP=82216 | HR=6234 | SAO=121865 | WDS=16478+0515 }}<ref name=SIMBAD/>
}}
{{Starbox reference
 | Simbad=45+Her
}}
{{Starbox end}}

'''45 Herculis''' is a binary [variable star](/source/variable_star) in the northern [constellation](/source/constellation) [Hercules](/source/Hercules_(constellation)). It has the [Bayer designation](/source/Bayer_designation) '''l Herculis''' and the [variable star designation](/source/variable_star_designation) '''V776 Herculis'''. The [Flamsteed designation](/source/Flamsteed_designation) for this star comes from the publication ''Historia Coelestis Britannica'' by [John Flamsteed](/source/John_Flamsteed). It is the 45th star in Flamsteed list of stars in the constellation Hercules, and is visible to the naked eye with a baseline [apparent visual magnitude](/source/apparent_visual_magnitude) of 5.22.<ref name=Ducati/> [Parallax](/source/Parallax) measurements show this star to be about 400&nbsp;[light-year](/source/light-year)s away from the [Solar System](/source/Solar_System).<ref name=GaiaDR2/> It is moving closer to the Earth with a heliocentric [radial velocity](/source/radial_velocity) of −16&nbsp;km/s.<ref name=GCRV/>

Cowley et at. (1969) assigned this object a classification of {{nowrap|B9p Cr}},<ref name=Cowley1969/> while Abt and Morrell (1995) found a class of {{nowrap|A1 Vp Si}}.<ref name=abt1995/> Both indicate this is a [late](/source/Late-type_star) [B-](/source/B-type_star) or [early](/source/Early-type_star) [A-type](/source/A-type_star) [chemically peculiar](/source/chemically_peculiar_star), or [Ap star](/source/Ap_and_Bp_stars), with abundance anomalies in chromium or silicon. It is classified as a magnetic Ap star, although its magnetic field is unusually weak for a star of this class.<ref name=Kochukhov/> It is an [Alpha<sup>2</sup> Canum Venaticorum variable](/source/Alpha2_Canum_Venaticorum_variable) that ranges in visual magnitude from 5.21 down to 5.27.<ref name=Samus2017/> The star has 2.9<ref name=Martin2017/> times the [mass of the Sun](/source/mass_of_the_Sun) and 4.9<ref name=shulyak2014/> times the [Sun's radius](/source/Sun's_radius). It is radiating 120<ref name=Anderson2012/> times the [Sun's luminosity](/source/Sun's_luminosity) from its [photosphere](/source/photosphere) at an [effective temperature](/source/effective_temperature) of 9,333&nbsp;K.<ref name=Wolff1967/>  The exact [evolutionary state](/source/stellar_evolution) of 45 Her is unclear, but it is near the end of its [main sequence](/source/main_sequence) life—just before, on, or shortly after the [hook](/source/Hook_(stellar_evolution)) that marks the transition to a [subgiant](/source/subgiant).<ref name=Kochukhov/>

Although 45 Herculis was long thought to be a solitary star,<ref name=Eggleton2008/> a 2023 study confirmed that 45 Herculis is a single-lined [spectroscopic binary](/source/spectroscopic_binary). The pair of stars orbit each other every 99.51 days on a moderately eccentric orbit. The secondary star is likely a low-mass star.<ref name=Kochukhov>{{cite journal | doi=10.1093/mnras/stad720 | doi-access=free | title=Surface structure of 45 Hercules: An otherwise unremarkable Ap star with a surprisingly weak magnetic field | date=2023 | last1=Kochukhov | first1=O. | last2=Gürsoytrak Mutlay | first2=H. | last3=Amarsi | first3=A. M. | last4=Petit | first4=P. | last5=Mutlay | first5=I. | last6=Gürol | first6=B. | journal=Monthly Notices of the Royal Astronomical Society | volume=521 | issue=3 | pages=3480–3499 | arxiv=2303.03862 | bibcode=2023MNRAS.521.3480K }}</ref>

==References==
<references>
<ref name=SIMBAD>{{cite simbad | title=45 Her | access-date=2019-06-14 }}</ref>

<ref name=GaiaDR2>{{Cite Gaia DR2|4434820128469285248}}</ref>

<ref name="Burke">{{cite journal |last1=Burke |first1=E. W. Jr. |last2=Barr |first2=T. H. |title=Photometric UBV period study of eight AP stars |journal=Publications of the Astronomy Society of the Pacific |date=June 1981 |volume=93 |pages=344–350 |doi=10.1086/130836 |bibcode=1981PASP...93..344B |s2cid=122946991 |doi-access=free }}</ref>

<ref name=Anderson2012>{{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 | arxiv=1108.4971
 | doi=10.1134/S1063773712050015 | s2cid=119257644 }}</ref>

<ref name=Eggleton2008>{{cite journal
 | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A.
 | title=A catalogue of multiplicity among bright stellar systems
 | journal=Monthly Notices of the Royal Astronomical Society
 | volume=389 | issue=2 | pages=869–879 | date=September 2008
 | doi=10.1111/j.1365-2966.2008.13596.x
 | doi-access=free | bibcode=2008MNRAS.389..869E | arxiv=0806.2878 | s2cid=14878976 }}</ref>

<ref name=Ducati>{{cite journal
 | title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system
 | journal=CDS/ADC Collection of Electronic Catalogues
 | last1=Ducati | first1=J. R.
 | volume=2237 | year=2002 | bibcode=2002yCat.2237....0D }}</ref>

<ref name=abt1995>{{cite journal
 | last1=Abt | first1=Helmut A. | last2=Morrell | first2=Nidia I.
 | title=The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars
 | journal=Astrophysical Journal Supplement
 | volume=99 | pages=135 | year=1995
 | bibcode=1995ApJS...99..135A | doi=10.1086/192182 | doi-access=free }}</ref>

<ref name=EgUBV>{{cite journal
 | last1=Mermilliod | first1=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=GCRV>{{cite journal
 | last=Wilson | first=Ralph Elmer
 | title=General catalogue of stellar radial velocities
 | journal=Carnegie Institute Washington D.C. Publication
 | date=1953 | bibcode=1953GCRV..C......0W }}</ref>

<ref name=Martin2017>{{cite journal
 | title=An Investigation of the Rotational Properties of Magnetic Chemically Peculiar Stars
 | first1=Martin | last1=Netopil | first2=Ernst | last2=Paunzen
 | first3=Stefan | last3=Huemmerich | first4=Klaus | last4=Bernhard
 | journal=Monthly Notices of the Royal Astronomical Society
 | volume=468 | issue=3 | pages=2745–2756 | date=July 2017
 | bibcode=2017MNRAS.468.2745N | arxiv=1703.05218 | doi=10.1093/mnras/stx674 | doi-access=free | s2cid=119215348 }}</ref>

<ref name=shulyak2014>{{cite journal
 | last1=Shulyak | first1=D. | last2=Paladini | first2=C.
 | last3=Causi | first3=G. Li | last4=Perraut | first4=K.
 | last5=Kochukhov | first5=O. | display-authors=1
 | title=Interferometry of chemically peculiar stars: Theoretical predictions versus modern observing facilities
 | journal=Monthly Notices of the Royal Astronomical Society
 | volume=443 | issue=2 | pages=1629 | year=2014
 | bibcode=2014MNRAS.443.1629S | arxiv=1406.6093
 | doi=10.1093/mnras/stu1259 | doi-access=free | s2cid=96452769 }}</ref>

<ref name=Wolff1967>{{cite journal
 | last1=Wolff | first1=Sidney Carne
 | title=A Spectroscopic and Photometric Study of the AP Stars
 | journal=Astrophysical Journal Supplement
 | volume=15 | page=21 |date=October 1967
 | doi=10.1086/190162 | bibcode=1967ApJS...15...21W | doi-access=free }}</ref>

<ref name=Royer2002>{{cite journal
 | display-authors=1 | last1=Royer | first1=F.
 | last2=Grenier | first2=S. | last3=Baylac | first3=M.-O.
 | last4=Gómez | first4=A. E. | last5=Zorec | first5=J.
 | title=Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i
 | journal=Astronomy and Astrophysics
 | volume=393 | pages=897–911 | date=October 2002
 | doi=10.1051/0004-6361:20020943 | bibcode=2002A&A...393..897R
 | arxiv=astro-ph/0205255 | s2cid=14070763 }}</ref>

<ref name=Cowley1969>{{cite journal | display-authors=1
 | last1=Cowley | first1=A. | last2=Cowley | first2=C.
 | last3=Jaschek | first3=M. | last4=Jaschek | first4=C.
 | title=A study of the bright A stars. I. A catalogue of spectral classifications
 | journal=Astronomical Journal
 | volume=74 | pages=375–406 | date=April 1969
 | doi=10.1086/110819 | bibcode=1969AJ.....74..375C }}</ref>

<ref name=Samus2017>{{cite journal
 | display-authors=1 | last1=Samus | first1=N. N.
 | last2=Kazarovets | first2=E. V. | last3=Durlevich | first3=O. V.
 | last4=Kireeva | first4=N. N. | last5=Pastukhova | first5=E. N.
 | title=General Catalogue of Variable Stars
 | version=5.1 | journal=Astronomy Reports
 | year=2017 | volume=61 | issue=1 | pages=80–88
 | bibcode=2017ARep...61...80S | doi=10.1134/S1063772917010085 | s2cid=125853869 }}</ref>
</references>

{{Stars of Hercules}}

Category:A-type main-sequence stars
Category:B-type main-sequence stars
Category:Ap stars
Category:Alpha2 Canum Venaticorum variables
Category:Spectroscopic binaries
Category:Hercules (constellation)
Herculis, l
Category:Durchmusterung objects
Herculis, 045
151525
082216
6234
Herculis, V776

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Adapted from the Wikipedia article [45 Herculis](https://en.wikipedia.org/wiki/45_Herculis) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/45_Herculis?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.