{{Short description|Star in the constellation Hercules}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=Hercules constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=111 Herculis |x=108|y=788 }} | caption = Location of 111 Herculis (circled in red) }} {{Starbox observe | epoch = J2000 | constell = Hercules | ra = {{RA|18|47|01.23431}}<ref name=GaiaDR3/> | dec = {{DEC|+21|46|53.4578}}<ref name=GaiaDR3/> | appmag_v = 4.34<ref name=Anderson2012/> }} {{Starbox character | type = main sequence<ref name=GaiaDR3/> | class = A3Va+<ref name=mk/> | b-v = {{Val|0.148|0.003}}<ref name=Anderson2012/> | u-b = | variable = }} {{Starbox astrometry | radial_v = {{Val|−44.6|2.7}}<ref name=Anderson2012/> | prop_mo_ra = +98.835<ref name=GaiaDR3/> | prop_mo_dec = +115.120<ref name=GaiaDR3/> | parallax = 34.9987 | p_error = 0.1743 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = 2.04<ref name=Anderson2012/> }} {{Starbox detail | source = | mass = 2.40<ref name=David2015/> | radius = 1.6<ref name=lang2006/> | temperature = {{Val|8873|302|fmt=commas}}<ref name=David2015/> | luminosity = 12.84<ref name=Anderson2012/> | gravity = 4.35<ref name=David2015/> | metal_fe = 0.33<ref name=Erspamer2003/> | rotational_velocity = 71<ref name=David2015/> | age_myr = 559<ref name=David2015/> }} {{Starbox catalog | names = {{odlist | F=111 Her | BD=+18°3823 | FK5=1491 | HD=173880 | HIP=92161 | HR=7069 | SAO=104093 | WDS=J18470+1811 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad=111+Her }} {{Starbox end}}
'''111 Herculis''' is a suspected astrometric binary<ref name=Eggleton2008/> star system located 92 light years from the Sun in the northern constellation Hercules. It is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 4.34.<ref name=Anderson2012/> The system is moving nearer to the Earth with a heliocentric radial velocity of −45 km/s, and may come as close as {{Convert|11.26|pc|ly|0|disp=out|abbr=off}} in 537,000 years.<ref name=Anderson2012/>
According to Garrison (1989), the visible component has a spectral classification if A3Va+, indicating an A-type main sequence star. Other authors have published classes of A5III,<ref name=Cowley1969/> matching an A-type giant star, and A3IV, suggesting it is instead a subgiant star.<ref name=abt1995/> Models of the star's evolution suggest that it is still on the main sequence.<ref name=GaiaDR3/>
The interferometry-measured angular diameter of the primary component is {{Val|0.52|0.02|ul=mas}},<ref name=Richichi2005/> which, at its estimated distance, equates to a physical radius of roughly 1.6 times the radius of the Sun.<ref name=lang2006/> The star is estimated to be 559<ref name=David2015/> million years old with 2.40<ref name=David2015/> times the mass of the Sun and is spinning with a projected rotational velocity of 71 km/s.<ref name=David2015/> It is radiating 13 times the Sun's luminosity from its photosphere at an effective temperature of 8,873 K.<ref name=David2015/>
==References== <references> <ref name=SIMBAD>{{cite simbad | title=111 Her | access-date=2019-06-18 }}</ref>
<ref name=GaiaDR3>{{Cite Gaia DR3|4512265810537057664}}</ref>
<ref name=mk>{{cite journal |last1=Gray |first1=R. O. |last2=Garrison |first2=R. F. |title=The Late A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation |journal=The Astrophysical Journal Supplement Series |date=1989 |volume=70 |page=623 |doi=10.1086/191349 |bibcode=1989ApJS...70..623G }}</ref>
<ref name=Anderson2012>{{citation | title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | postscript=. | 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>{{citation | 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 | postscript=. }}</ref>
<ref name=Cowley1969>{{citation | 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=David2015>{{citation | last1=David | first1=Trevor J. | last2=Hillenbrand | first2=Lynne A. | title=The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets | journal=The Astrophysical Journal | postscript=. | volume=804 | issue=2 | pages=146 | year=2015 | bibcode=2015ApJ...804..146D | arxiv=1501.03154 | doi=10.1088/0004-637X/804/2/146 | s2cid=33401607 }}</ref>
<ref name=Erspamer2003>{{citation | title=Automated spectroscopic abundances of A and F-type stars using echelle spectrographs. II. Abundances of 140 A-F stars from ELODIE | last1=Erspamer | first1=D. | last2=North | first2=P. | journal=Astronomy and Astrophysics | volume=398 | pages=1121–1135 | date=February 2003 | issue=3 | doi=10.1051/0004-6361:20021711 | arxiv=astro-ph/0210065 | bibcode=2003A&A...398.1121E | s2cid=1109164 | postscript=. }}</ref>
<ref name=Richichi2005>{{citation | last1=Richichi | first1=A. | last2=Percheron | first2=I. | last3=Khristoforova | first3=M. | title=CHARM2: An updated Catalog of High Angular Resolution Measurements | journal=Astronomy and Astrophysics | volume=431 | pages=773–777 | date=February 2005 | issue=2 | doi=10.1051/0004-6361:20042039 | bibcode=2005A&A...431..773R | doi-access=free }}</ref>
<ref name=lang2006>{{citation | postscript=. | first1=Kenneth R. | last1=Lang | title=Astrophysical formulae | volume=1 | series=Astronomy and astrophysics library | edition=3rd | publisher=Birkhäuser | date=2006 | isbn=3-540-29692-1 | url=https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 }} The radius (R<sub>*</sub>) is given by: :<math>\begin{align} 2\cdot R_* & = \frac{(10^{-3}\cdot 28.3\cdot 0.52)\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\ & \approx 3.2\cdot R_{\bigodot} \end{align}</math></ref>
<ref name=abt1995>{{citation | 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 | postscript=. | bibcode=1995ApJS...99..135A | doi=10.1086/192182 | doi-access=free }}</ref> </references>
{{Stars of Hercules}}
{{DEFAULTSORT:111 Herculis}} Category:A-type giants Category:A-type subgiants Category:Astrometric binaries Category:Hercules (constellation) BD+18 3823 Herculis, 111 173880 092161 7069