{{Short description|Star in the constellation Hercules}} {{Starbox begin}} {{Starbox image | image = 250px | caption = An ultraviolet band light curve for V776 Herculis, adapted from Burke and Barr (1981)<ref name="Burke"/> }} {{Starbox observe | epoch = J2000 | constell = Hercules | 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 or 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<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 Her | F=45 Her | V=V776 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 in the northern constellation Hercules. It has the Bayer designation '''l Herculis''' and the variable star designation '''V776 Herculis'''. The Flamsteed designation for this star comes from the publication ''Historia Coelestis Britannica'' by 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 of 5.22.<ref name=Ducati/> Parallax measurements show this star to be about 400 light-years away from the Solar System.<ref name=GaiaDR2/> It is moving closer to the Earth with a heliocentric radial velocity of −16 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 B- or early A-type chemically peculiar, or Ap star, 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 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 and 4.9<ref name=shulyak2014/> times the Sun's radius. It is radiating 120<ref name=Anderson2012/> times the Sun's luminosity from its photosphere at an effective temperature of 9,333 K.<ref name=Wolff1967/> The exact evolutionary state of 45 Her is unclear, but it is near the end of its main sequence life—just before, on, or shortly after the hook that marks the transition to a 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. 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