The widest two components of the system are easily separated when viewed through binoculars, or even with the naked eye under excellent conditions.[9]
The northern component is called ε1 (ADS 11635 AB in multiple star notation) and the southern ε2 (ADS 11635 CD); they lie around 160 light years from Earth and orbit each other over hundreds of thousands of years. Their separation of 208″ is about one hundred times that of the subcomponents. When viewed at higher magnifications, each intuitively likely "star" proves to be a set of shorter-term, close-orbiting binary stars. Ability to view these sub-components is a common benchmark for the resolving power of telescopes, since they are so close together: the stars of ε1 were 2.35 arc-seconds apart in 2006, those of ε2 were separated by about the same amount in that year. Since the first high-precision measurements of their orbit in the 1980s, both binaries have moved only a few degrees in position angle.
The component stars of ε1 have magnitudes of 4.7 and 6.2 separated by 2.6" and have an orbital period that can only be crudely estimated at 1200 years, which places them at roughly 140 AU apart. Main components of ε2 have magnitudes 5.1 and 5.5 separated by 2.3", and orbit in perhaps half that period. ε1 and ε2 are more than 0.16 light years apart. An observer at one pair would see the other as strongly as a quarter-illuminated Moon (which is about mv = −5.0), less than a degree away from each other.[10][11]
In 2022, researchers at MarSEC (Marana Space Explorer Center) thanks to data from the TESS (Transiting Exoplanet Survey Satellite) discovered that the secondary component of ε1 is a variable star of the type Gamma Doradus with a main period of 0.415 days.[12]
The fifth component of this system, orbiting one of the ε2 pair, was detected by speckle interferometry in 1985 and confirmed in two later observations. No orbit can be prepared from such limited data, but its rapid motion suggests a period of a few tens of years. Its maximum observed separation of 0.2 arc-seconds precludes direct visual observation.
A further five nearby dimmer stars are also listed in multiple star catalogues:[13]
^ abcdefghijvan Leeuwen, F.; et al. (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.
^ abcdefMermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
^ abAbt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". Astrophysical Journal Supplement. 95: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
^Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
^Kharchenko, N. V.; et al. (2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten. 328 (9): 889. arXiv:0705.0878. Bibcode:2007AN....328..889K. doi:10.1002/asna.200710776. S2CID 119323941.
^ abcdefghijklmnopZorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. S2CID 55586789.
^Dawes, W R (1867). Catalogue of Micrometrical Measurements of Double Stars. Royal Astronomical Society. p. 409.
^ ab Burnham, Robert (1966). Burnham's Celestial Handbook. Dover Publications Inc. pp. 1151–1153. ISBN0-486-24064-9.
^Jim Kaler. "Epsilon Lyrae". Kaler's Stars. Retrieved 18 November 2013.
^ ab. Archived from the original on 17 May 2011. Retrieved 19 December 2010.
^. Archived from the original on 12 April 2009. Retrieved 19 December 2010.
External linksedit
Epsilon Lyrae -- The Double Double
Epsilon Lyrae
January 01, 1970
epsilon, lyrae, double, double, redirects, here, other, uses, double, double, disambiguation, lyrae, also, known, double, double, multiple, star, system, least, five, stars, approximately, light, years, away, constellation, lyra, circled, constellation, lyra, . The Double Double redirects here For other uses see double double disambiguation Epsilon Lyrae e Lyr e Lyrae also known as the Double Double 8 is a multiple star system of at least five stars approximately 162 light years away in the constellation of Lyra Epsilon Lyraee circled in the constellation Lyra Observation dataEpoch J2000 0 Equinox J2000 0 Constellation Lyra Epsilon1 Lyrae Right ascension 18h 44m 20 34589s 1 Declination 39 40 12 4533 1 Apparent magnitude V 4 66 2 Epsilon2 Lyrae Right ascension 18h 44m 22 78056s 1 Declination 39 36 45 7851 1 Apparent magnitude V 4 59 2 Characteristics e1 Lyr Spectral type A3V F0V 3 U B color index 0 065 2 B V color index 0 16 2 e2 Lyr Spectral type A6Vn A7Vn 3 U B color index 0 075 2 B V color index 0 18 2 Astrometrye1 LyrRadial velocity Rv 31 20 1 7 4 km sProper motion m RA 11 09 1 mas yr Dec 61 39 1 mas yrParallax p 20 10 0 76 mas 1 Distance162 6 ly 50 2 pc Absolute magnitude MV 1 2 5 e2 LyrRadial velocity Rv 24 40 1 7 6 km sProper motion m RA 6 18 1 mas yr Dec 50 42 1 mas yrParallax p 20 97 0 50 mas 1 Distance156 4 ly 48 1 pc Absolute magnitude MV 1 2 5 Detailse1 Lyr AMass2 03 7 M Luminosity24 7 L Temperature7 943 7 KRotational velocity v sin i 165 7 km se1 Lyr BMass1 61 7 M Luminosity8 4 7 L Temperature7 047 7 KRotational velocity v sin i 159 7 km s e2 Lyr AMass2 11 7 M Luminosity29 7 L Temperature7 816 7 KRotational velocity v sin i 212 7 km se2 Lyr BMass2 15 7 M Luminosity32 7 L Temperature7 852 7 KRotational velocity v sin i 233 7 km s Other designationsADS 11635 WDS 18443 3940e1 Lyr 4 Lyrae HIP 91919 BD 39 3509e1 Lyr A HD 173582 HR 7051 SAO 67310e1 Lyr B HD 173583 HR 7052 SAO 67309 Other designationse2 Lyr 5 Lyrae HIP 91926 BD 39 3510e2 Lyr A HD 173607 HR 7053 SAO 67315e2 Lyr B HD 173608 HR 7054 Database referencese1 Lyre1 Lyr Ae1 Lyr Be2 Lyre2 Lyr Ae2 Lyr BStar system edit nbsp Epsilon Lyrae the Double DoubleThe widest two components of the system are easily separated when viewed through binoculars or even with the naked eye under excellent conditions 9 The northern component is called e1 ADS 11635 AB in multiple star notation and the southern e2 ADS 11635 CD they lie around 160 light years from Earth and orbit each other over hundreds of thousands of years Their separation of 208 is about one hundred times that of the subcomponents When viewed at higher magnifications each intuitively likely star proves to be a set of shorter term close orbiting binary stars Ability to view these sub components is a common benchmark for the resolving power of telescopes since they are so close together the stars of e1 were 2 35 arc seconds apart in 2006 those of e2 were separated by about the same amount in that year Since the first high precision measurements of their orbit in the 1980s both binaries have moved only a few degrees in position angle The component stars of e1 have magnitudes of 4 7 and 6 2 separated by 2 6 and have an orbital period that can only be crudely estimated at 1200 years which places them at roughly 140 AU apart Main components of e2 have magnitudes 5 1 and 5 5 separated by 2 3 and orbit in perhaps half that period e1 and e2 are more than 0 16 light years apart An observer at one pair would see the other as strongly as a quarter illuminated Moon which is about mv 5 0 less than a degree away from each other 10 11 In 2022 researchers at MarSEC Marana Space Explorer Center thanks to data from the TESS Transiting Exoplanet Survey Satellite discovered that the secondary component of e1is a variable star of the type Gamma Doradus with a main period of 0 415 days 12 The fifth component of this system orbiting one of the e2 pair was detected by speckle interferometry in 1985 and confirmed in two later observations No orbit can be prepared from such limited data but its rapid motion suggests a period of a few tens of years Its maximum observed separation of 0 2 arc seconds precludes direct visual observation A further five nearby dimmer stars are also listed in multiple star catalogues 13 Multiple star components Magnitude Spectral Type A 5 15 A2 B 6 10 A4 C 5 25 A3 D 5 38 A5 E 11 71 F 11 2 G 13 83 H 13 22 I 10 43 Cb Orbit pairs 9 13 14 Separation when arcsec Separation when au Most Recent when Position Angle Period years Semi major axis arcseconds Notes AB CD 208 2 10 500 172 e1 e2 AB 2 3 116 347 1804 41 4 742 components of e1 CD 2 4 121 79 724 307 2 92 components of e2 Ca Cb 0 1 5 225 recently discoveredinterferometric companionReferences edit a b c d e f g h i j van Leeuwen F et al 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 e f 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 Abt Helmut A Morrell Nidia I 1995 The Relation between Rotational Velocities and Spectral Peculiarities among A Type Stars Astrophysical Journal Supplement 95 135 Bibcode 1995ApJS 99 135A doi 10 1086 192182 Gontcharov G A 2006 Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system Astronomy Letters 32 11 759 771 arXiv 1606 08053 Bibcode 2006AstL 32 759G doi 10 1134 S1063773706110065 S2CID 119231169 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 Kharchenko N V et al 2007 Astrophysical supplements to the ASCC 2 5 Ia Radial velocities of 55000 stars and mean radial velocities of 516 Galactic open clusters and associations Astronomische Nachrichten 328 9 889 arXiv 0705 0878 Bibcode 2007AN 328 889K doi 10 1002 asna 200710776 S2CID 119323941 a b c d e f g h i j k l m n o p Zorec J Royer F 2012 Rotational velocities of A type stars IV Evolution of rotational velocities Astronomy and Astrophysics 537 A120 arXiv 1201 2052 Bibcode 2012A amp A 537A 120Z doi 10 1051 0004 6361 201117691 S2CID 55586789 Dawes W R 1867 Catalogue of Micrometrical Measurements of Double Stars Royal Astronomical Society p 409 a b Burnham Robert 1966 Burnham s Celestial Handbook Dover Publications Inc pp 1151 1153 ISBN 0 486 24064 9 Jim Kaler Epsilon Lyrae Kaler s Stars Retrieved 18 November 2013 Epsilon Lyrae the Double Double VSX Detail for eps 1 Lyr B a b Washington Double Star Catalog Archived from the original on 17 May 2011 Retrieved 19 December 2010 Sixth Orbit Catalog Archived from the original on 12 April 2009 Retrieved 19 December 2010 External links editEpsilon Lyrae The Double Double Epsilon Lyrae Retrieved from https en wikipedia org w index php title Epsilon Lyrae amp oldid 1203007800, wikipedia, wiki, book, books, library,
