Star in the constellation Hercules
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.[ 3] Parallax measurements show this star to be about 400 light-years away from the Solar System .[ 2] It is moving closer to the Earth with a heliocentric radial velocity of −16 km/s.[ 15]
Cowley et at. (1969) assigned this object a classification of B9p Cr ,[ 5] while Abt and Morrell (1995) found a class of A1 Vp Si .[ 4] 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.[ 8] It is an Alpha2 Canum Venaticorum variable that ranges in visual magnitude from 5.21 down to 5.27.[ 7] The star has 2.9[ 10] times the mass of the Sun and 4.9[ 11] times the Sun's radius . It is radiating 120[ 9] times the Sun's luminosity from its photosphere at an effective temperature of 9,333 K.[ 12]
Although 45 Herculis was long thought to be a solitary star,[ 16] 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.[ 8]
^ Burke, E. W. Jr.; Barr, T. H. (June 1981). "Photometric UBV period study of eight AP stars" . Publications of the Astronomy Society of the Pacific . 93 : 344–350. Bibcode :1981PASP...93..344B . doi :10.1086/130836 . S2CID 122946991 .
^ a b c d e f Brown, A. G. A. ; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties" . Astronomy & Astrophysics . 616 . A1. arXiv :1804.09365 . Bibcode :2018A&A...616A...1G . doi :10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR .
^ a b Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues . 2237 . Bibcode :2002yCat.2237....0D .
^ a b Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars" . Astrophysical Journal Supplement . 99 : 135. Bibcode :1995ApJS...99..135A . doi :10.1086/192182 .
^ a b Cowley, A.; et al. (April 1969). "A study of the bright A stars. I. A catalogue of spectral classifications". Astronomical Journal . 74 : 375–406. Bibcode :1969AJ.....74..375C . doi :10.1086/110819 .
^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data . Bibcode :1986EgUBV........0M .
^ a b Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports . 5.1. 61 (1): 80–88. Bibcode :2017ARep...61...80S . doi :10.1134/S1063772917010085 . S2CID 125853869 .
^ a b c d e f g Kochukhov, O.; Gürsoytrak Mutlay, H.; Amarsi, A. M.; Petit, P.; Mutlay, I.; Gürol, B. (2023). "Surface structure of 45 Hercules: An otherwise unremarkable Ap star with a surprisingly weak magnetic field" . Monthly Notices of the Royal Astronomical Society . 521 (3): 3480–3499. arXiv :2303.03862 . Bibcode :2023MNRAS.521.3480K . doi :10.1093/mnras/stad720 .
^ a b Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters . 38 (5): 331. arXiv :1108.4971 . Bibcode :2012AstL...38..331A . doi :10.1134/S1063773712050015 . S2CID 119257644 .
^ a b Netopil, Martin; Paunzen, Ernst; Huemmerich, Stefan; Bernhard, Klaus (July 2017). "An Investigation of the Rotational Properties of Magnetic Chemically Peculiar Stars" . Monthly Notices of the Royal Astronomical Society . 468 (3): 2745–2756. arXiv :1703.05218 . Bibcode :2017MNRAS.468.2745N . doi :10.1093/mnras/stx674 . S2CID 119215348 .
^ a b Shulyak, D.; et al. (2014). "Interferometry of chemically peculiar stars: Theoretical predictions versus modern observing facilities" . Monthly Notices of the Royal Astronomical Society . 443 (2): 1629. arXiv :1406.6093 . Bibcode :2014MNRAS.443.1629S . doi :10.1093/mnras/stu1259 . S2CID 96452769 .
^ a b c Wolff, Sidney Carne (October 1967). "A Spectroscopic and Photometric Study of the AP Stars" . Astrophysical Journal Supplement . 15 : 21. Bibcode :1967ApJS...15...21W . doi :10.1086/190162 .
^ Royer, F.; et al. (October 2002). "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i". Astronomy and Astrophysics . 393 : 897–911. arXiv :astro-ph/0205255 . Bibcode :2002A&A...393..897R . doi :10.1051/0004-6361:20020943 . S2CID 14070763 .
^ "45 Her" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-06-14 .
^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication . Bibcode :1953GCRV..C......0W .
^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems" . Monthly Notices of the Royal Astronomical Society . 389 (2): 869–879. arXiv :0806.2878 . Bibcode :2008MNRAS.389..869E . doi :10.1111/j.1365-2966.2008.13596.x . S2CID 14878976 .