The primary star rotates rapidly with a projected equatorial velocity of 440 km/s. Due to its rapid rotation, the primary star has a polar radius about 5.5 R☉ and an equatorial radius of about 8.0 R☉. With an effective temperature of nearly 30,000 K, it has a bolometric luminosity nearly 15,000 times higher than the Sun. The rapidly-spinning star is surrounded by a circumstellar disk. The binary orbit, the spin of the primary star, and the disk are all seen nearly edge-on. There are no eclipses, but models of the system show that the disk significantly obscures the primary star.[5] The primary formed as a 3.8 M☉ star and has accreted material from its companion.[9]
The secondary star is also a class O subdwarf, hotter than the primary but smaller and less massive. It is proposed that it is the core of a 7 M☉ star, with the outer layers stripped as it expanded away from the main sequence. Its luminosity is higher than expected for a normal 1.2 M☉helium star, which suggests it may have evolved to helium shell burning.[9] Although the subdwarf has a bolometric luminosity about half that of the primary, it emits most of its radiation as ultraviolet, being only about 3% as bright as the primary at visible wavelengths.[5]
Phi Persei is a variable star with both rapid and longterm variations in its brightness and spectrum. Variations occur on a daily timescale which may be related to the rotation of the primary star. Any variations originating with the secondary are difficult to detect due to its comparative faintness. Slower variations, including deep fades, are also seen. Some of the variations may correspond to the orbital period, possibly eclipses of gas streams or hot spots, but the occasional deep fades do not match any particular orbital phase. The variations are classified as γ Cassiopeiae-type, shell stars with eruptions and irregular fading.[12]
Namingedit
Flamsteed followed Ptolemy in treating φ Persei as being in Andromeda and gave it the designation54 Andromedae. It is isolated from the main stars of Perseus, but lies within its formal borders.[13]
^ abcdeVan Leeuwen, F. (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. Vizier catalog entry
^ abcDucati, 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.
^ abSamus, 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.
^Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050. Bibcode:1995yCat.5050....0H.
^ abcdMourard, D.; Monnier, J. D.; Meilland, A.; Gies, D.; Millour, F.; Benisty, M.; Che, X.; Grundstrom, E. D.; Ligi, R.; Schaefer, G.; Baron, F.; Kraus, S.; Zhao, M.; Pedretti, E.; Berio, P.; Clausse, J. M.; Nardetto, N.; Perraut, K.; Spang, A.; Stee, P.; Tallon-Bosc, I.; McAlister, H.; Ten Brummelaar, T.; Ridgway, S. T.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C. (2015). "Spectral and spatial imaging of the Be+sdO binary ϕ Persei". Astronomy & Astrophysics. 577: A51. arXiv:1503.03423. Bibcode:2015A&A...577A..51M. doi:10.1051/0004-6361/201425141. S2CID 16766856.
^Wilson, R. E. (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Carnegie Institution for Science. Bibcode:1953GCRV..C......0W. LCCN 54001336.
^ abcGies, Douglas R.; Bagnuolo, William G.; Ferrara, Elizabeth C.; Kaye, Anthony B.; Thaller, Michelle L.; Penny, Laura R.; Peters, Geraldine J. (1998). "Hubble Space Telescope Goddard High Resolution Spectrograph Observations of the Be + sdO Binary φ Persei". The Astrophysical Journal. 493 (1): 440–450. Bibcode:1998ApJ...493..440G. doi:10.1086/305113. S2CID 121635926.
^. Archived from the original on 1 August 2017. Retrieved 29 December 2016.
^ abcdefghiSchootemeijer, A.; Götberg, Y.; De Mink, S. E.; Gies, D.; Zapartas, E. (2018). "Clues about the scarcity of stripped-envelope stars from the evolutionary state of the sdO+Be binary system φ Persei". Astronomy and Astrophysics. 615: A30. arXiv:1803.02379. Bibcode:2018A&A...615A..30S. doi:10.1051/0004-6361/201731194. S2CID 59471417.
^ abZorec, J.; Frémat, Y.; Domiciano De Souza, A.; Royer, F.; Cidale, L.; Hubert, A.-M.; Semaan, T.; Martayan, C.; Cochetti, Y. R.; Arias, M. L.; Aidelman, Y.; Stee, P. (2017). "Critical study of the distribution of rotational velocities of Be stars". Astronomy & Astrophysics. 595: A132. arXiv:1702.07684. Bibcode:2016A&A...595A.132Z. doi:10.1051/0004-6361/201628760.
^ abcKrtička, J.; Kubát, J.; Krtičková, I. (2016). "Stellar wind models of subluminous hot stars". Astronomy & Astrophysics. 593: A101. arXiv:1607.04445. Bibcode:2016A&A...593A.101K. doi:10.1051/0004-6361/201628433. S2CID 118390374.
^ abBožić, H.; Harmanec, P.; Horn, J.; Koubský, P.; Scholz, G.; McDavid, D.; Hubert, A. M.; Hubert, H. (December 1995). "Toward a consistent model of the B0.5IVe + sdO binary φ Persei". Astronomy and Astrophysics. 304: 235–257.
^Wagman, M. (August 1987). "Flamsteed's Missing Stars". Journal for the History of Astronomy. 18 (3): 212. Bibcode:1987JHA....18..209W. doi:10.1177/002182868701800305. S2CID 118445625.
^(in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 10 日
External linksedit
HST Press release on the φ Per binary system
January 01, 1970
persei, persei, class, b2vep, fourth, magnitude, star, constellation, perseus, location, about, light, years, from, earth, perseilocation, persei, circled, observation, dataepoch, j2000, equinox, j2000, constellation, perseus, right, ascension, 63792s, declina. Phi Persei Phi Per f Persei f Per is a class B2Vep fourth magnitude star in the constellation Perseus location about 720 light years from Earth f PerseiLocation of f Persei circled Observation dataEpoch J2000 Equinox J2000 Constellation Perseus Right ascension 01h 43m 39 63792s 1 Declination 50 41 19 4328 1 Apparent magnitude V 4 06 2 3 96 4 11 3 Characteristics Spectral type B2Vep 4 sdO 5 U B color index 0 92 2 B V color index 0 04 2 Variable type g Cas 3 AstrometryRadial velocity Rv 0 80 6 km sProper motion m RA 24 59 1 mas yr Dec 14 01 1 mas yrParallax p 4 54 0 20 mas 1 Distance720 30 ly 220 10 pc Absolute magnitude MV 3 11 7 Orbit 7 8 Period P 126 6731 daysSemi major axis a 5 89 masInclination i 77 6 Longitude of the node W 295 7 Periastron epoch T 2456110 03Semi amplitude K1 primary 9 97 km sSemi amplitude K2 secondary 81 3 km s DetailsAMass9 6 9 M Radius5 5 8 0 7 R Luminosity14 454 9 L Surface gravity log g 4 46 10 cgsTemperature29 300 9 KRotational velocity v sin i 440 10 km sBMass1 14 11 M Radius1 3 11 R Luminosity6 310 9 L Surface gravity log g 4 2 9 cgsTemperature53 000 11 KAge57 9 9 Myr Other designationsf Persei f Per Phi Per 54 Andromedae BD 49 444 FK5 57 GC 2102 HD 10516 HIP 8068 HR 496 PPM 26670 SAO 22554 Database referencesSIMBADdata Contents 1 System 2 Variability 3 Naming 4 References 5 External linksSystem edit nbsp f Persei in optical light Phi Persei is spectroscopic binary consisting of a blue main sequence primary of class B2 and a hot subdwarf secondary The two stars have an orbit of 217 days and are separated by about 200 R 9 Phi Persei is a runaway star and extrapolating its space velocity backwards by the modelled age of the system 57 million years places it within the Alpha Persei cluster 5 The primary star rotates rapidly with a projected equatorial velocity of 440 km s Due to its rapid rotation the primary star has a polar radius about 5 5 R and an equatorial radius of about 8 0 R With an effective temperature of nearly 30 000 K it has a bolometric luminosity nearly 15 000 times higher than the Sun The rapidly spinning star is surrounded by a circumstellar disk The binary orbit the spin of the primary star and the disk are all seen nearly edge on There are no eclipses but models of the system show that the disk significantly obscures the primary star 5 The primary formed as a 3 8 M star and has accreted material from its companion 9 The secondary star is also a class O subdwarf hotter than the primary but smaller and less massive It is proposed that it is the core of a 7 M star with the outer layers stripped as it expanded away from the main sequence Its luminosity is higher than expected for a normal 1 2 M helium star which suggests it may have evolved to helium shell burning 9 Although the subdwarf has a bolometric luminosity about half that of the primary it emits most of its radiation as ultraviolet being only about 3 as bright as the primary at visible wavelengths 5 Variability edit nbsp A blue light light curve for Phi Persei adapted from Bozic et al 1995 12 Phi Persei is a variable star with both rapid and longterm variations in its brightness and spectrum Variations occur on a daily timescale which may be related to the rotation of the primary star Any variations originating with the secondary are difficult to detect due to its comparative faintness Slower variations including deep fades are also seen Some of the variations may correspond to the orbital period possibly eclipses of gas streams or hot spots but the occasional deep fades do not match any particular orbital phase The variations are classified as g Cassiopeiae type shell stars with eruptions and irregular fading 12 Naming editFlamsteed followed Ptolemy in treating f Persei as being in Andromeda and gave it the designation 54 Andromedae It is isolated from the main stars of Perseus but lies within its formal borders 13 In Chinese 天大將軍 Tian Da Jiang Jun meaning Heaven s Great General refers to an asterism consisting of f Persei g Andromedae 51 Andromedae 49 Andromedae x Andromedae y Andromedae t Andromedae 56 Andromedae b Trianguli g Trianguli and d Trianguli Consequently the Chinese name for f Persei itself is 天大將軍二 Tian Da Jiang Jun er English the Second Star of Heaven s Great General 14 References edit a b c d e Van Leeuwen F 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 Vizier catalog entry a b c 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 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 Hoffleit D Warren W H 1995 VizieR Online Data Catalog Bright Star Catalogue 5th Revised Ed Hoffleit 1991 VizieR On line Data Catalog V 50 Originally Published in 1964BS C 0H 5050 Bibcode 1995yCat 5050 0H a b c d Mourard D Monnier J D Meilland A Gies D Millour F Benisty M Che X Grundstrom E D Ligi R Schaefer G Baron F Kraus S Zhao M Pedretti E Berio P Clausse J M Nardetto N Perraut K Spang A Stee P Tallon Bosc I McAlister H Ten Brummelaar T Ridgway S T Sturmann J Sturmann L Turner N Farrington C 2015 Spectral and spatial imaging of the Be sdO binary ϕ Persei Astronomy amp Astrophysics 577 A51 arXiv 1503 03423 Bibcode 2015A amp A 577A 51M doi 10 1051 0004 6361 201425141 S2CID 16766856 Wilson R E 1953 General Catalogue of Stellar Radial Velocities Carnegie Institute Washington D C Publication Carnegie Institution for Science Bibcode 1953GCRV C 0W LCCN 54001336 a b c Gies Douglas R Bagnuolo William G Ferrara Elizabeth C Kaye Anthony B Thaller Michelle L Penny Laura R Peters Geraldine J 1998 Hubble Space Telescope Goddard High Resolution Spectrograph Observations of the Be sdO Binary f Persei The Astrophysical Journal 493 1 440 450 Bibcode 1998ApJ 493 440G doi 10 1086 305113 S2CID 121635926 Sixth Catalog of Orbits of Visual Binary Stars Archived from the original on 1 August 2017 Retrieved 29 December 2016 a b c d e f g h i Schootemeijer A Gotberg Y De Mink S E Gies D Zapartas E 2018 Clues about the scarcity of stripped envelope stars from the evolutionary state of the sdO Be binary system f Persei Astronomy and Astrophysics 615 A30 arXiv 1803 02379 Bibcode 2018A amp A 615A 30S doi 10 1051 0004 6361 201731194 S2CID 59471417 a b Zorec J Fremat Y Domiciano De Souza A Royer F Cidale L Hubert A M Semaan T Martayan C Cochetti Y R Arias M L Aidelman Y Stee P 2017 Critical study of the distribution of rotational velocities of Be stars Astronomy amp Astrophysics 595 A132 arXiv 1702 07684 Bibcode 2016A amp A 595A 132Z doi 10 1051 0004 6361 201628760 a b c Krticka J Kubat J Krtickova I 2016 Stellar wind models of subluminous hot stars Astronomy amp Astrophysics 593 A101 arXiv 1607 04445 Bibcode 2016A amp A 593A 101K doi 10 1051 0004 6361 201628433 S2CID 118390374 a b Bozic H Harmanec P Horn J Koubsky P Scholz G McDavid D Hubert A M Hubert H December 1995 Toward a consistent model of the B0 5IVe sdO binary f Persei Astronomy and Astrophysics 304 235 257 Wagman M August 1987 Flamsteed s Missing Stars Journal for the History of Astronomy 18 3 212 Bibcode 1987JHA 18 209W doi 10 1177 002182868701800305 S2CID 118445625 in Chinese AEEA Activities of Exhibition and Education in Astronomy 天文教育資訊網 2006 年 7 月 10 日External links editHST Press release on the f Per binary system Retrieved from https en wikipedia org w index php title Phi Persei amp oldid 1181447262, wikipedia, wiki, book, books, library,
