The brightness of φ Draconis varies by about 0.04 of a magnitude every 1.7 days. This is due to very strong magnetic fields at the surface of the star, and it is classified as an α2 Canum Venaticorum variable.[2]
φ Draconis is a multiple star system containing three stars. The inner pair form a single-lined spectroscopic binary in an eccentric 128-day orbit. The outermost star orbits the inner pair every 308 years. The outer pair can be resolved visually and have a semi-major axis of 0.752″. A fourth component, C, is also listed in multiple star catalogues, but is only a chance alignment with the triple system.[4]
Phi Draconis Aa is a main-sequence Ap star with a spectral class of B8. The main abundance excess is silicon, although iron and chromium and also notably elevated.[10]
^ abcdevan Leeuwen, F. (November 2007). "Hipparcos, the New Reduction" (VizieR). Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Retrieved 2010-11-22.
^ abcSamus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
^Gray, R. O.; Corbally, C. J. (2014). "An Expert Computer Program for Classifying Stars on the MK Spectral Classification System". The Astronomical Journal. 147 (4): 80. Bibcode:2014AJ....147...80G. doi:10.1088/0004-6256/147/4/80. S2CID 28584130.
^ abcdefgLiška, J. (2016). "Analysis of the multiple system with chemically peculiar component φ Draconis". Monthly Notices of the Royal Astronomical Society. 461 (1): 939–947. arXiv:1606.01333. Bibcode:2016MNRAS.461..939L. doi:10.1093/mnras/stw1355.
^ abMermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. (PDF) origin: SIMBAD: 0. Bibcode:1986EgUBV........0M.
^ abcdKochukhov, O.; Papakonstantinou, N.; Neiner, C. (2022). "Magnetic field topology, chemical spot distributions, and photometric variability of the Ap star φ Draconis". Monthly Notices of the Royal Astronomical Society. 510 (4): 5821. arXiv:2201.02554. Bibcode:2022MNRAS.510.5821K. doi:10.1093/mnras/stac066.
^ abcdNorth, P. (June 1998). "Do SI stars undergo any rotational braking?". Astronomy and Astrophysics. 334: 181–187. arXiv:astro-ph/9802286. Bibcode:1998A&A...334..181N.
^"MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
^Prvák, M.; Liška, J.; Krtička, J.; Mikulášek, Z.; Lüftinger, T. (2015). "Modelling of variability of the chemically peculiar star ϕ Draconis". Astronomy and Astrophysics. 584: A17. arXiv:1510.01192. Bibcode:2015A&A...584A..17P. doi:10.1051/0004-6361/201526647.
^(in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 10 日
External linksEdit
Jim Kaler's Stars, University of Illinois: PHI DRA (Phi Draconis)
An Atlas of the Universe: Multiple Star Orbits
October 16, 2023
draconis, draconis, fourth, magnitude, variable, star, constellation, draco, flamsteed, designation, draconis, also, triple, star, system, where, brightest, component, chemically, peculiar, star, draconislocation, draconis, circled, observation, dataepoch, j20. Phi Draconis f Dra f Draconis is a fourth magnitude variable star in the constellation Draco It has the Flamsteed designation 43 Draconis It is also a triple star system where the brightest component is a chemically peculiar Ap star f DraconisLocation of f Draconis circled Observation dataEpoch J2000 Equinox J2000Constellation DracoRight ascension 18h 20m 45 43224s 1 Declination 71 20 16 1499 1 Apparent magnitude V 4 22 2 CharacteristicsSpectral type B8VpSi 3 A4V B9V 4 U B color index 0 38 5 B V color index 0 10 5 Variable type a2 CVn 2 AstrometryRadial velocity Rv 16 44 6 km sProper motion m RA 5 03 1 mas yr Dec 37 86 1 mas yrParallax p 10 77 0 38 mas 1 Distance300 10 ly 93 3 pc Absolute magnitude MV 0 74 0 48 0 94 4 Orbit 4 PrimaryACompanionBPeriod P 307 8 yrSemi major axis a 0 965 89 60 au Eccentricity e 0 752Inclination i 95 6 Orbit 6 PrimaryAaCompanionAbPeriod P 127 914 dEccentricity e 0 6725Inclination i 48 Semi amplitude K1 primary 33 87 km sDetailsAaMass3 3 4 M Radius2 7 0 2 7 R Luminosity107 7 L Surface gravity log g 4 21 0 08 7 cgsTemperature11 429 7 KRotation1 7165 6 Rotational velocity v sin i 81 5 6 km sAge245 4 MyrAbMass1 36 8 M BMass2 25 8 M Age330 4 MyrOther designationsf Dra 43 Dra BD 71 889 CCDM J18208 7120AB GC 25114 HD 170000 HIP 89908 HR 6920 SAO 9084Database referencesSIMBADdata A light curve for Phi Draconis plotted from TESS data 9 The brightness of f Draconis varies by about 0 04 of a magnitude every 1 7 days This is due to very strong magnetic fields at the surface of the star and it is classified as an a2 Canum Venaticorum variable 2 f Draconis is a multiple star system containing three stars The inner pair form a single lined spectroscopic binary in an eccentric 128 day orbit The outermost star orbits the inner pair every 308 years The outer pair can be resolved visually and have a semi major axis of 0 752 A fourth component C is also listed in multiple star catalogues but is only a chance alignment with the triple system 4 Phi Draconis Aa is a main sequence Ap star with a spectral class of B8 The main abundance excess is silicon although iron and chromium and also notably elevated 10 In Chinese astronomy f Draconis is called 柱史 Pinyin Zhushǐ meaning Official of Royal Archives because this star is marking itself and stand alone in Official of Royal Archives asterism Purple Forbidden enclosure see Chinese constellations 11 References Edit a b c d e van Leeuwen F November 2007 Hipparcos the New Reduction VizieR Astronomy and Astrophysics 474 2 653 664 arXiv 0708 1752 Bibcode 2007A amp A 474 653V doi 10 1051 0004 6361 20078357 S2CID 18759600 Retrieved 2010 11 22 a b c Samus N N Durlevich O V et al 2009 VizieR Online Data Catalog General Catalogue of Variable Stars Samus 2007 2013 VizieR On line Data Catalog B GCVS Originally Published in 2009yCat 102025S 1 Bibcode 2009yCat 102025S Gray R O Corbally C J 2014 An Expert Computer Program for Classifying Stars on the MK Spectral Classification System The Astronomical Journal 147 4 80 Bibcode 2014AJ 147 80G doi 10 1088 0004 6256 147 4 80 S2CID 28584130 a b c d e f g Liska J 2016 Analysis of the multiple system with chemically peculiar component f Draconis Monthly Notices of the Royal Astronomical Society 461 1 939 947 arXiv 1606 01333 Bibcode 2016MNRAS 461 939L doi 10 1093 mnras stw1355 a b Mermilliod J C 1986 Compilation of Eggen s UBV data transformed to UBV unpublished Catalogue of Eggen s UBV Data PDF origin SIMBAD 0 Bibcode 1986EgUBV 0M a b c d Kochukhov O Papakonstantinou N Neiner C 2022 Magnetic field topology chemical spot distributions and photometric variability of the Ap star f Draconis Monthly Notices of the Royal Astronomical Society 510 4 5821 arXiv 2201 02554 Bibcode 2022MNRAS 510 5821K doi 10 1093 mnras stac066 a b c d North P June 1998 Do SI stars undergo any rotational braking Astronomy and Astrophysics 334 181 187 arXiv astro ph 9802286 Bibcode 1998A amp A 334 181N a b Tokovinin Andrei 2018 03 01 The Updated Multiple Star Catalog The Astrophysical Journal Supplement Series 235 1 6 arXiv 1712 04750 Bibcode 2018ApJS 235 6T doi 10 3847 1538 4365 aaa1a5 ISSN 0067 0049 S2CID 119047709 MAST Barbara A Mikulski Archive for Space Telescopes Space Telescope Science Institute Retrieved 8 December 2021 Prvak M Liska J Krticka J Mikulasek Z Luftinger T 2015 Modelling of variability of the chemically peculiar star ϕ Draconis Astronomy and Astrophysics 584 A17 arXiv 1510 01192 Bibcode 2015A amp A 584A 17P doi 10 1051 0004 6361 201526647 in Chinese AEEA Activities of Exhibition and Education in Astronomy 天文教育資訊網 2006 年 6 月 10 日External links EditJim Kaler s Stars University of Illinois PHI DRA Phi Draconis An Atlas of the Universe Multiple Star Orbits Retrieved from https en wikipedia org w index php title Phi Draconis amp oldid 1136206011, wikipedia, wiki, book, books, library,
