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Epsilon Librae

Epsilon Librae (ε Lib) is the Bayer designation for a binary star system in the zodiac constellation Libra. With an apparent visual magnitude of 4.922,[2] it is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 32.02 mas,[1] it is located about 102 light years away from the Sun.

Epsilon Librae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Libra
Right ascension 15h 24m 11.89101s[1]
Declination −10° 19′ 20.1740″[1]
Apparent magnitude (V) 4.922[2]
Characteristics
Spectral type F3 V[3] or F5 IV[4]
U−B color index +0.080[2]
B−V color index +0.451[2]
Astrometry
Proper motion (μ) RA: −66.52[1] mas/yr
Dec.: −154.24[1] mas/yr
Parallax (π)32.02 ± 0.72 mas[1]
Distance102 ± 2 ly
(31.2 ± 0.7 pc)
Absolute magnitude (MV)2.37[5]
Orbit[6]
Period (P)226.9437±0.0025 d
Semi-major axis (a)0.85192±0.00359 au
Eccentricity (e)0.6649±0.0014
Inclination (i)52.6±9.4[7]°
Periastron epoch (T)2453593.022 ± 0.041 HJD[8]
Argument of periastron (ω)
(secondary)
339.84±0.15°
Details
ε Lib A
Mass1.17±0.02[6] M
Radius1.5[9] R
Luminosity9.3[10] L
Surface gravity (log g)4.13[10] cgs
Temperature6,552±80[6] K
Metallicity [Fe/H]+0.09[10] dex
Rotational velocity (v sin i)10[5] km/s
Age1.5[10] Gyr
ε Lib B
Mass0.410±0.004[6] M
Other designations
ε Lib, 31 Lib, BD−09° 4138, HD 137052, HIP 75379, HR 5723, SAO 159234.[11]
Database references
SIMBADdata

This is a single-lined spectroscopic binary star system. The pair orbit each other with a period of 226.9 days and an eccentricity of 0.66.[6] The semimajor axis of their orbit is estimated to be 0.85 AU, or 85% of the distance from the Earth to the Sun. The primary, component A, has been catalogued with stellar classifications of F3 V[3] and F5 IV,[4] suggesting that it is an F-type star that either belongs to the main sequence or has evolved into a subgiant as the hydrogen at its core nears exhaustion.

The primary has an estimated 1.17[6] times the mass of the Sun and 1.5 times the Sun's radius. It is around 1.5[10] billion years old and is spinning with a projected rotational velocity of 10[5] km/s. The star radiates 9.3[10] times the solar luminosity from its outer atmosphere at an effective temperature of 6,552 K.[6] The secondary, component B, has 41% of the Sun's mass.[6]

References edit

  1. ^ a b c d e f van 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.
  2. ^ a b c d Celis, L. (October 1975), "Photoelectric photometry of late-type variable stars", Astronomy and Astrophysics Supplement Series, 22: 9–17, Bibcode:1975A&AS...22....9C.
  3. ^ a b Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, 5, Ann Arbor, Michigan: Department of Astronomy, University of Michigan, Bibcode:1999MSS...C05....0H.
  4. ^ a b Malaroda, S. (August 1975), "Study of the F-type stars. I. MK spectral types", Astronomical Journal, 80: 637–641, Bibcode:1975AJ.....80..637M, doi:10.1086/111786.
  5. ^ a b c Takeda, Yoichi; et al. (February 2005), "High-Dispersion Spectra Collection of Nearby F--K Stars at Okayama Astrophysical Observatory: A Basis for Spectroscopic Abundance Standards", Publications of the Astronomical Society of Japan, 57 (1): 13–25, Bibcode:2005PASJ...57...13T, doi:10.1093/pasj/57.1.13.
  6. ^ a b c d e f g h Katoh, Noriyuki; et al. (February 2013), "Determination of Orbital Elements of Spectroscopic Binaries Using High-dispersion Spectroscopy", The Astronomical Journal, 145 (2): 12, Bibcode:2013AJ....145...41K, doi:10.1088/0004-6256/145/2/41, 41.
  7. ^ Jancart, S. (2005), "Astrometric orbits of SB9 stars", Astronomy and Astrophysics, 442 (1): 365–380, arXiv:astro-ph/0507695, Bibcode:2005A&A...442..365J, doi:10.1051/0004-6361:20053003, S2CID 15123997.
  8. ^ Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy & Astrophysics, 424 (2): 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
  9. ^ Pasinetti-Fracassini, L. E.; et al. (February 2001), "Catalog of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (3rd ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
  10. ^ a b c d e f Takeda, Yoichi (April 2007), "Fundamental Parameters and Elemental Abundances of 160 F-G-K Stars Based on OAO Spectrum Database", Publications of the Astronomical Society of Japan, 59 (2): 335–356, Bibcode:2007PASJ...59..335T, doi:10.1093/pasj/59.2.335.
  11. ^ "eps Lib -- Spectroscopic binary", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-01-30.

epsilon, librae, bayer, designation, binary, star, system, zodiac, constellation, libra, with, apparent, visual, magnitude, bright, enough, seen, with, naked, based, upon, annual, parallax, shift, located, about, light, years, away, from, observation, dataepoc. Epsilon Librae e Lib is the Bayer designation for a binary star system in the zodiac constellation Libra With an apparent visual magnitude of 4 922 2 it is bright enough to be seen with the naked eye Based upon an annual parallax shift of 32 02 mas 1 it is located about 102 light years away from the Sun Epsilon Librae Observation dataEpoch J2000 0 Equinox J2000 0 ICRS Constellation Libra Right ascension 15h 24m 11 89101s 1 Declination 10 19 20 1740 1 Apparent magnitude V 4 922 2 Characteristics Spectral type F3 V 3 or F5 IV 4 U B color index 0 080 2 B V color index 0 451 2 AstrometryProper motion m RA 66 52 1 mas yr Dec 154 24 1 mas yrParallax p 32 02 0 72 mas 1 Distance102 2 ly 31 2 0 7 pc Absolute magnitude MV 2 37 5 Orbit 6 Period P 226 9437 0 0025 dSemi major axis a 0 85192 0 00359 auEccentricity e 0 6649 0 0014Inclination i 52 6 9 4 7 Periastron epoch T 2453593 022 0 041 HJD 8 Argument of periastron w secondary 339 84 0 15 Detailse Lib AMass1 17 0 02 6 M Radius1 5 9 R Luminosity9 3 10 L Surface gravity log g 4 13 10 cgsTemperature6 552 80 6 KMetallicity Fe H 0 09 10 dexRotational velocity v sin i 10 5 km sAge1 5 10 Gyre Lib BMass0 410 0 004 6 M Other designationse Lib 31 Lib BD 09 4138 HD 137052 HIP 75379 HR 5723 SAO 159234 11 Database referencesSIMBADdata This is a single lined spectroscopic binary star system The pair orbit each other with a period of 226 9 days and an eccentricity of 0 66 6 The semimajor axis of their orbit is estimated to be 0 85 AU or 85 of the distance from the Earth to the Sun The primary component A has been catalogued with stellar classifications of F3 V 3 and F5 IV 4 suggesting that it is an F type star that either belongs to the main sequence or has evolved into a subgiant as the hydrogen at its core nears exhaustion The primary has an estimated 1 17 6 times the mass of the Sun and 1 5 times the Sun s radius It is around 1 5 10 billion years old and is spinning with a projected rotational velocity of 10 5 km s The star radiates 9 3 10 times the solar luminosity from its outer atmosphere at an effective temperature of 6 552 K 6 The secondary component B has 41 of the Sun s mass 6 References edit a b c d e f 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 a b c d Celis L October 1975 Photoelectric photometry of late type variable stars Astronomy and Astrophysics Supplement Series 22 9 17 Bibcode 1975A amp AS 22 9C a b Houk N Swift C 1999 Michigan catalogue of two dimensional spectral types for the HD Stars Michigan Spectral Survey 5 Ann Arbor Michigan Department of Astronomy University of Michigan Bibcode 1999MSS C05 0H a b Malaroda S August 1975 Study of the F type stars I MK spectral types Astronomical Journal 80 637 641 Bibcode 1975AJ 80 637M doi 10 1086 111786 a b c Takeda Yoichi et al February 2005 High Dispersion Spectra Collection of Nearby F K Stars at Okayama Astrophysical Observatory A Basis for Spectroscopic Abundance Standards Publications of the Astronomical Society of Japan 57 1 13 25 Bibcode 2005PASJ 57 13T doi 10 1093 pasj 57 1 13 a b c d e f g h Katoh Noriyuki et al February 2013 Determination of Orbital Elements of Spectroscopic Binaries Using High dispersion Spectroscopy The Astronomical Journal 145 2 12 Bibcode 2013AJ 145 41K doi 10 1088 0004 6256 145 2 41 41 Jancart S 2005 Astrometric orbits of SB9 stars Astronomy and Astrophysics 442 1 365 380 arXiv astro ph 0507695 Bibcode 2005A amp A 442 365J doi 10 1051 0004 6361 20053003 S2CID 15123997 Pourbaix D Tokovinin A A Batten A H Fekel F C Hartkopf W I et al 2004 SB9 The ninth catalogue of spectroscopic binary orbits Astronomy amp Astrophysics 424 2 727 732 arXiv astro ph 0406573 Bibcode 2004A amp A 424 727P doi 10 1051 0004 6361 20041213 S2CID 119387088 Pasinetti Fracassini L E et al February 2001 Catalog of Apparent Diameters and Absolute Radii of Stars CADARS Astronomy and Astrophysics 367 3rd ed 521 524 arXiv astro ph 0012289 Bibcode 2001A amp A 367 521P doi 10 1051 0004 6361 20000451 S2CID 425754 a b c d e f Takeda Yoichi April 2007 Fundamental Parameters and Elemental Abundances of 160 F G K Stars Based on OAO Spectrum Database Publications of the Astronomical Society of Japan 59 2 335 356 Bibcode 2007PASJ 59 335T doi 10 1093 pasj 59 2 335 eps Lib Spectroscopic binary SIMBAD Astronomical Database Centre de Donnees astronomiques de Strasbourg retrieved 2017 01 30 Retrieved from https en wikipedia org w index php title Epsilon Librae amp oldid 1187475352, wikipedia, wiki, book, books, library,

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