The primary member is a subgiant star that is somewhat larger than the Sun and has just begun to evolve away from the main sequence as the supply of hydrogen at its core becomes exhausted. It is orbited by a smaller companion star at a mean angular separation of 1.5 arcseconds, which corresponds to a physical separation of about 15 Astronomical Units.[6] This distance is large enough so that the two stars do not have a significant tidal effect on each other. The stars orbit each other over a period of 34.45 years, with a semi-major axis of 1.33" and an eccentricity of 0.46.[7]
Component A has a stellar classification of F9 IV.[3] It has about 2.6 times the radius of the Sun and 1.45 times the Sun's mass. This star is radiating more than six times the luminosity of the Sun at an effective temperature of 5,820 K. The secondary component (Component B) is about the same size and mass as the Sun, with an effective temperature of 5,300 K. Both stars are rotating slowly.[6] There may be a faint third member of this system, although little is known about it.[9]
The dual nature of this system was reported by F. G. W. Struve in 1826.[10] The pair orbit each other with a period of 34.45 years and an eccentricity of 0.46.[7] The magnitude difference between the A-B pair is 1.52 ± 0.04 magnitudes (at 700 nm).[11] Two astrometric studies have failed to detect a third component to the A-B binary.[11][7]
^ abcdefvan Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600
^ abcdJohnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J
^ abEdwards, T. W. (April 1976), "MK classification for visual binary components", Astronomical Journal, 81: 245–249, Bibcode:1976AJ.....81..245E, doi:10.1086/111879
^Tokovinin, A. A.; Smekhov, M. G. (January 2002), "Statistics of spectroscopic sub-systems in visual multiple stars", Astronomy and Astrophysics, 382: 118–123, Bibcode:2002A&A...382..118T, doi:10.1051/0004-6361:20011586
^ abPizzolato, N.; Maggio, A.; Sciortino, S. (September 2000), "Evolution of X-ray activity of 1-3 Msun late-type stars in early post-main-sequence phases", Astronomy and Astrophysics, 361: 614–628, Bibcode:2000A&A...361..614P
^ abcdefghijklmMorel, P.; et al. (November 2001), "The zeta Herculis binary system revisited. Calibration and seismology", Astronomy and Astrophysics, 379: 245–256, arXiv:astro-ph/0110004, Bibcode:2001A&A...379..245M, doi:10.1051/0004-6361:20011336, S2CID 119514991
^ abcdSöderhjelm, Staffan (January 1999), "Visual binary orbits and masses POST HIPPARCOS", Astronomy and Astrophysics, 341: 121–140, Bibcode:1999A&A...341..121S
^Barry, Don C.; Cromwell, Richard H.; Hege, E. Keith (April 1987), "Chromospheric activity and ages of solar-type stars", Astrophysical Journal, Part 1, 315: 264–272, Bibcode:1987ApJ...315..264B, doi:10.1086/165131
^Zhuchkov, R. Ya.; Orlov, V. V.; Rubinov, A. V. (May 2006), "Multiple stars with low hierarchy: stable or unstable?", Publications of the Astronomical Observatory of Belgrade, 80: 155–160, Bibcode:2006POBeo..80..155Z
^Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
^ abHutter, D. J.; Zavala, R. T.; Tycner, C.; Benson, J. A.; Hummel, C. A.; Sanborn, J.; Franz, O. G.; Johnston, K. J. (2016-11-01). "Surveying the Bright Stars by Optical Interferometry. I. A Search for Multiplicity among Stars of Spectral Types F-K". The Astrophysical Journal Supplement Series. 227 (1): 4. arXiv:1609.05254. Bibcode:2016ApJS..227....4H. doi:10.3847/0067-0049/227/1/4. ISSN 0067-0049. S2CID 118803592.
^de Mello, G. F. Porto; da Silva, L. (1991), "On the physical existence of the Zeta HER moving group - A detailed analysis of Phi exp 2 Pavonis", Astronomical Journal, 102: 1816–1825, Bibcode:1991AJ....102.1816P, doi:10.1086/116006
Prof. Jim Kaler. "Zeta Herculis". Stars. Retrieved 2006-07-27.
January 01, 1970
zeta, herculis, latinized, from, herculis, multiple, star, system, constellation, hercules, combined, apparent, visual, magnitude, which, readily, visible, naked, parallax, measurements, distance, about, light, years, parsecs, from, earth, location, herculis, . Zeta Herculis Latinized from z Herculis is a multiple star system in the constellation Hercules It has a combined apparent visual magnitude of 2 81 2 which is readily visible to the naked eye Parallax measurements put it at a distance of about 35 0 light years 10 7 parsecs from Earth 1 Zeta HerculisLocation of z Herculis circled Observation dataEpoch J2000 Equinox J2000 Constellation Hercules Right ascension 16h 41m 17 16104s 1 Declination 31 36 09 7873 1 Apparent magnitude V 2 81 2 Characteristics Spectral type F9 IV G7 V 3 U B color index 0 21 2 B V color index 0 65 2 Variable type Suspected AstrometryRadial velocity Rv 68 43 4 km sProper motion m RA 461 52 1 mas yr Dec 342 28 1 mas yrParallax p 93 32 0 47 mas 1 Distance35 0 0 2 ly 10 72 0 05 pc Absolute magnitude MV 2 65 5 Absolute bolometricmagnitude Mbol 2 699 5 254 6 Orbit 7 Period P 34 45 yrSemi major axis a 1 33 Eccentricity e 0 46Inclination i 131 Longitude of the node W 50 Periastron epoch T 1967 7Argument of periastron w secondary 111 Detailsz Her AMass1 45 0 01 6 M Radius2 56 2 61 6 R Luminosity6 55 0 39 6 L Surface gravity log g 3 4 3 6 6 cgsTemperature5 820 50 6 KMetallicity Fe H 0 04 0 003 6 dexRotational velocity v sin i 4 8 5 km sAge6 2 8 Gyrz Her BMass0 98 0 02 6 M Radius0 915 0 920 6 R Luminosity0 62 0 06 6 L Temperature5 300 150 6 K Other designationsz Her 40 Her BD 31 2884 GJ 635 HD 150680 HIP 81693 HR 6212 SAO 65485 ADS 10157 AB WDS J16413 3136AB LHS 3234 LTT 14952 Database referencesSIMBADdata The primary member is a subgiant star that is somewhat larger than the Sun and has just begun to evolve away from the main sequence as the supply of hydrogen at its core becomes exhausted It is orbited by a smaller companion star at a mean angular separation of 1 5 arcseconds which corresponds to a physical separation of about 15 Astronomical Units 6 This distance is large enough so that the two stars do not have a significant tidal effect on each other The stars orbit each other over a period of 34 45 years with a semi major axis of 1 33 and an eccentricity of 0 46 7 Component A has a stellar classification of F9 IV 3 It has about 2 6 times the radius of the Sun and 1 45 times the Sun s mass This star is radiating more than six times the luminosity of the Sun at an effective temperature of 5 820 K The secondary component Component B is about the same size and mass as the Sun with an effective temperature of 5 300 K Both stars are rotating slowly 6 There may be a faint third member of this system although little is known about it 9 The dual nature of this system was reported by F G W Struve in 1826 10 The pair orbit each other with a period of 34 45 years and an eccentricity of 0 46 7 The magnitude difference between the A B pair is 1 52 0 04 magnitudes at 700 nm 11 Two astrometric studies have failed to detect a third component to the A B binary 11 7 This system forms part of the Zeta Herculis moving group of stars This group includes f2 Pavonis z Reticuli 1 Hydrae Gl 456 Gl 678 and Gl 9079 12 References edit a b c d e f van Leeuwen F November 2007 Validation of the new Hipparcos reduction Astronomy and Astrophysics 474 2 653 664 arXiv 0708 1752 Bibcode 2007A amp A 474 653V doi 10 1051 0004 6361 20078357 S2CID 18759600 a b c d Johnson H L et al 1966 UBVRIJKL photometry of the bright stars Communications of the Lunar and Planetary Laboratory 4 99 99 Bibcode 1966CoLPL 4 99J a b Edwards T W April 1976 MK classification for visual binary components Astronomical Journal 81 245 249 Bibcode 1976AJ 81 245E doi 10 1086 111879 Tokovinin A A Smekhov M G January 2002 Statistics of spectroscopic sub systems in visual multiple stars Astronomy and Astrophysics 382 118 123 Bibcode 2002A amp A 382 118T doi 10 1051 0004 6361 20011586 a b Pizzolato N Maggio A Sciortino S September 2000 Evolution of X ray activity of 1 3 Msun late type stars in early post main sequence phases Astronomy and Astrophysics 361 614 628 Bibcode 2000A amp A 361 614P a b c d e f g h i j k l m Morel P et al November 2001 The zeta Herculis binary system revisited Calibration and seismology Astronomy and Astrophysics 379 245 256 arXiv astro ph 0110004 Bibcode 2001A amp A 379 245M doi 10 1051 0004 6361 20011336 S2CID 119514991 a b c d Soderhjelm Staffan January 1999 Visual binary orbits and masses POST HIPPARCOS Astronomy and Astrophysics 341 121 140 Bibcode 1999A amp A 341 121S Barry Don C Cromwell Richard H Hege E Keith April 1987 Chromospheric activity and ages of solar type stars Astrophysical Journal Part 1 315 264 272 Bibcode 1987ApJ 315 264B doi 10 1086 165131 Zhuchkov R Ya Orlov V V Rubinov A V May 2006 Multiple stars with low hierarchy stable or unstable Publications of the Astronomical Observatory of Belgrade 80 155 160 Bibcode 2006POBeo 80 155Z Mason B D et al 2014 The Washington Visual Double Star Catalog The Astronomical Journal 122 6 3466 3471 Bibcode 2001AJ 122 3466M doi 10 1086 323920 a b Hutter D J Zavala R T Tycner C Benson J A Hummel C A Sanborn J Franz O G Johnston K J 2016 11 01 Surveying the Bright Stars by Optical Interferometry I A Search for Multiplicity among Stars of Spectral Types F K The Astrophysical Journal Supplement Series 227 1 4 arXiv 1609 05254 Bibcode 2016ApJS 227 4H doi 10 3847 0067 0049 227 1 4 ISSN 0067 0049 S2CID 118803592 de Mello G F Porto da Silva L 1991 On the physical existence of the Zeta HER moving group A detailed analysis of Phi exp 2 Pavonis Astronomical Journal 102 1816 1825 Bibcode 1991AJ 102 1816P doi 10 1086 116006External links edit Gl 635 ARICNS Retrieved 2006 07 27 zet Her SIMBAD Centre de donnees astronomiques de Strasbourg Retrieved 2006 07 27 Prof Jim Kaler Zeta Herculis Stars Retrieved 2006 07 27 Retrieved from https en wikipedia org w index php title Zeta Herculis amp oldid 1186944409, wikipedia, wiki, book, books, library,
