# HD 134687

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This article is about e Lupi; not to be confused with [ε Lupi](/source/Epsilon_Lupi).

Binary star system in the constellation of Lupus

HD 134687 Location of HD 134687 (circled in red) Observation data Epoch J2000 Equinox J2000 Constellation Lupus[1] Right ascension 15h 12m 49.58752s[2] Declination −44° 30′ 01.4904″[2] Apparent magnitude (V) 4.81[3] Characteristics Evolutionary stage main sequence[2] Spectral type B3 IV/V[4] B−V color index −0.177±0.011[1] Astrometry Radial velocity (Rv) +13.5±7.4[5] km/s Proper motion (μ) RA: −21.669[2] mas/yr Dec.: −21.895[2] mas/yr Parallax (π) 7.2373±0.2045 mas[2] Distance 450 ± 10 ly (138 ± 4 pc) Absolute magnitude (MV) −1.11[1] Orbit[6] Period (P) 0.901407 d Eccentricity (e) ≤ 0.03 Periastron epoch (T) 0.366 Details e Lup A Mass 6.0±0.1[7] M☉ Radius 7.1[8] R☉ Luminosity (bolometric) 997[3] L☉ Temperature 17,100[3] K Rotational velocity (v sin i) 13[9] km/s Age 20.3±4.8 Myr Other designations e Lup, CD−44°9932, HD 134687, HIP 74449, HR 5651, SAO 225539[10] Database references SIMBAD data

**HD 134687** (**e Lupi**) is a [binary star](/source/Binary_star) system in the southern [constellation](/source/Constellation) [Lupus](/source/Lupus_(constellation)). It is visible to the naked eye with an [apparent visual magnitude](/source/Apparent_visual_magnitude) of 4.81.[3] The distance to HD 134687 can be estimated from its annual [parallax shift](/source/Stellar_parallax) of 7.2 [mas](/source/Milliarcsecond),[2] yielding roughly 450 [light years](/source/Light_year). It is a member of the ~11 million year old Upper Centaurus–Lupus subgroup of the [Scorpius–Centaurus association](/source/Scorpius%E2%80%93Centaurus_association), the closest [OB association](/source/OB_association) to the Sun.[11]

This is a single-lined [spectroscopic binary](/source/Spectroscopic_binary) star system. The pair have a nearly circular orbit with an [eccentricity](/source/Orbital_eccentricity) of at or below 0.03 and a [period](/source/Orbital_period) of 0.901407 days (21.6338 h). The primary has an *a* sin *i* value of 2.735×105 km, which only gives a lower bound for the [semimajor axis](/source/Semimajor_axis) *a* since the [orbital inclination](/source/Orbital_inclination) *i* to the line of sight is unknown.[6] The system is a source for [X-ray emission](/source/X-ray_astronomy).[12]

The visible component has a [stellar classification](/source/Stellar_classification) of B3 IV/V,[4] matching a [B-type star](/source/B-type_star) showing a [spectrum](/source/Stellar_spectrum) with mixed traits of a [main sequence](/source/Main_sequence) and a [subgiant star](/source/Subgiant_star). It is 20 million years old with a [projected rotational velocity](/source/Projected_rotational_velocity) of 13 km/s.[9] The star has 6.0[7] times the [mass of the Sun](/source/Mass_of_the_Sun) and 7.1[8] times the [Sun's radius](/source/Sun's_radius). It is radiating 997[3] times the [Sun's luminosity](/source/Sun's_luminosity) from its [photosphere](/source/Photosphere) at an [effective temperature](/source/Effective_temperature) of 17,100 K.[3]

## References

1. ^ [***a***](#cite_ref-Anderson2012_1-0) [***b***](#cite_ref-Anderson2012_1-1) [***c***](#cite_ref-Anderson2012_1-2) Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". *[Astronomy Letters](/source/Astronomy_Letters)*. **38** (5): 331. [arXiv](/source/ArXiv_(identifier)):[1108.4971](https://arxiv.org/abs/1108.4971). [Bibcode](/source/Bibcode_(identifier)):[2012AstL...38..331A](https://ui.adsabs.harvard.edu/abs/2012AstL...38..331A). [doi](/source/Doi_(identifier)):[10.1134/S1063773712050015](https://doi.org/10.1134%2FS1063773712050015). [XHIP record for this object](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-ref=VIZ681510a8389ecb&-out.src=V%2F137D%2FXHIP&-nav=cat%3AV%2F137D%26tab%3A{V%2F137D%2FXHIP}%26key%3Asource%3DV%2F137D%2FXHIP%26HTTPPRM%3A&-source=V%2F137D%2FXHIP&-out=HIP&HIP=74449&-out=Comp&-out=Gr&-out=RAJ2000&-out=DEJ2000&-out=Dist&-out=X&-out=Y&-out=Z&-out=SpType&-out=Simbad&-out=Hpmag&-out=Lum&-out=Cst) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-GaiaDR3_2-0) [***b***](#cite_ref-GaiaDR3_2-1) [***c***](#cite_ref-GaiaDR3_2-2) [***d***](#cite_ref-GaiaDR3_2-3) [***e***](#cite_ref-GaiaDR3_2-4) [***f***](#cite_ref-GaiaDR3_2-5) [***g***](#cite_ref-GaiaDR3_2-6) Vallenari, A.; et al. (Gaia collaboration) (2023). ["*Gaia* Data Release 3. Summary of the content and survey properties"](https://doi.org/10.1051%2F0004-6361%2F202243940). *Astronomy and Astrophysics*. **674**: A1. [arXiv](/source/ArXiv_(identifier)):[2208.00211](https://arxiv.org/abs/2208.00211). [Bibcode](/source/Bibcode_(identifier)):[2023A&A...674A...1G](https://ui.adsabs.harvard.edu/abs/2023A&A...674A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202243940](https://doi.org/10.1051%2F0004-6361%2F202243940). [S2CID](/source/S2CID_(identifier)) [244398875](https://api.semanticscholar.org/CorpusID:244398875). [Gaia DR3 record for this source](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-source=+I%2F355&-from=nav&-nav=cat%3AI%2F355%26tab%3A%7BI%2F355%2Fgaiadr3%7D%26key%3Asource%3D1355%2Fgaiadr3%26HTTPPRM%3A%26-out.add%3D.%26Source%3D%3D%3D6003314456673154048%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-Hohle2010_3-0) [***b***](#cite_ref-Hohle2010_3-1) [***c***](#cite_ref-Hohle2010_3-2) [***d***](#cite_ref-Hohle2010_3-3) [***e***](#cite_ref-Hohle2010_3-4) [***f***](#cite_ref-Hohle2010_3-5) Hohle, M. M.; Neuhäuser, R.; Schutz, B. F. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", *Astronomische Nachrichten*, **331** (4): 349, [arXiv](/source/ArXiv_(identifier)):[1003.2335](https://arxiv.org/abs/1003.2335), [Bibcode](/source/Bibcode_(identifier)):[2010AN....331..349H](https://ui.adsabs.harvard.edu/abs/2010AN....331..349H), [doi](/source/Doi_(identifier)):[10.1002/asna.200911355](https://doi.org/10.1002%2Fasna.200911355), [S2CID](/source/S2CID_(identifier)) [111387483](https://api.semanticscholar.org/CorpusID:111387483).

1. ^ [***a***](#cite_ref-houk1978_4-0) [***b***](#cite_ref-houk1978_4-1) Houk, Nancy (1978), *Michigan catalogue of two-dimensional spectral types for the HD stars*, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, [Bibcode](/source/Bibcode_(identifier)):[1978mcts.book.....H](https://ui.adsabs.harvard.edu/abs/1978mcts.book.....H).

1. **[^](#cite_ref-deBruijne2012_5-0)** de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", *Astronomy & Astrophysics*, **546**: 14, [arXiv](/source/ArXiv_(identifier)):[1208.3048](https://arxiv.org/abs/1208.3048), [Bibcode](/source/Bibcode_(identifier)):[2012A&A...546A..61D](https://ui.adsabs.harvard.edu/abs/2012A&A...546A..61D), [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201219219](https://doi.org/10.1051%2F0004-6361%2F201219219), [S2CID](/source/S2CID_(identifier)) [59451347](https://api.semanticscholar.org/CorpusID:59451347), A61.

1. ^ [***a***](#cite_ref-Buscombe1962_6-0) [***b***](#cite_ref-Buscombe1962_6-1) Buscombe, W.; Kennedy, P. M. (August 1962), "Two B-Type Spectroscopic Binaries", *Publications of the Astronomical Society of the Pacific*, **74** (439): 323, [Bibcode](/source/Bibcode_(identifier)):[1962PASP...74..323B](https://ui.adsabs.harvard.edu/abs/1962PASP...74..323B), [doi](/source/Doi_(identifier)):[10.1086/127818](https://doi.org/10.1086%2F127818)

1. ^ [***a***](#cite_ref-Tetzlaff2011_7-0) [***b***](#cite_ref-Tetzlaff2011_7-1) Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", *[Monthly Notices of the Royal Astronomical Society](/source/Monthly_Notices_of_the_Royal_Astronomical_Society)*, **410** (1): 190–200, [arXiv](/source/ArXiv_(identifier)):[1007.4883](https://arxiv.org/abs/1007.4883), [Bibcode](/source/Bibcode_(identifier)):[2011MNRAS.410..190T](https://ui.adsabs.harvard.edu/abs/2011MNRAS.410..190T), [doi](/source/Doi_(identifier)):[10.1111/j.1365-2966.2010.17434.x](https://doi.org/10.1111%2Fj.1365-2966.2010.17434.x), [S2CID](/source/S2CID_(identifier)) [118629873](https://api.semanticscholar.org/CorpusID:118629873).

1. ^ [***a***](#cite_ref-cadars_8-0) [***b***](#cite_ref-cadars_8-1) Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", *Astronomy and Astrophysics*, **367** (2) (Third ed.): 521–524, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0012289](https://arxiv.org/abs/astro-ph/0012289), [Bibcode](/source/Bibcode_(identifier)):[2001A&A...367..521P](https://ui.adsabs.harvard.edu/abs/2001A&A...367..521P), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20000451](https://doi.org/10.1051%2F0004-6361%3A20000451), [S2CID](/source/S2CID_(identifier)) [425754](https://api.semanticscholar.org/CorpusID:425754).

1. ^ [***a***](#cite_ref-Wolff2007_9-0) [***b***](#cite_ref-Wolff2007_9-1) Wolff, S. C.; Strom, S. E.; Dror, D.; Venn, K. (2007), "Rotational Velocities for B0-B3 Stars in Seven Young Clusters: Further Study of the Relationship between Rotation Speed and Density in Star-Forming Regions", *[The Astronomical Journal](/source/The_Astronomical_Journal)*, **133** (3): 1092–1103, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0702133](https://arxiv.org/abs/astro-ph/0702133), [Bibcode](/source/Bibcode_(identifier)):[2007AJ....133.1092W](https://ui.adsabs.harvard.edu/abs/2007AJ....133.1092W), [doi](/source/Doi_(identifier)):[10.1086/511002](https://doi.org/10.1086%2F511002), [S2CID](/source/S2CID_(identifier)) [119074863](https://api.semanticscholar.org/CorpusID:119074863).

1. **[^](#cite_ref-SIMBAD_10-0)** ["HD 134687"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+134687). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 2018-07-22.

1. **[^](#cite_ref-Chen2012_11-0)** Chen, Christine H.; et al. (September 2012), "A Spitzer MIPS Study of 2.5–2.0 M☉ Stars in Scorpius–Centaurus", *The Astrophysical Journal*, **756** (2): 24, [arXiv](/source/ArXiv_(identifier)):[1207.3415](https://arxiv.org/abs/1207.3415), [Bibcode](/source/Bibcode_(identifier)):[2012ApJ...756..133C](https://ui.adsabs.harvard.edu/abs/2012ApJ...756..133C), [doi](/source/Doi_(identifier)):[10.1088/0004-637X/756/2/133](https://doi.org/10.1088%2F0004-637X%2F756%2F2%2F133), [S2CID](/source/S2CID_(identifier)) [119278056](https://api.semanticscholar.org/CorpusID:119278056), 133.

1. **[^](#cite_ref-Berghoefer1996_12-0)** Berghoefer, T. W.; Schmitt, J. H. M. M.; Cassinelli, J. P. (September 1996), "The ROSAT all-sky survey catalogue of optically bright OB-type stars", *Astronomy and Astrophysics Supplement*, **118** (3): 481–494, [Bibcode](/source/Bibcode_(identifier)):[1996A&AS..118..481B](https://ui.adsabs.harvard.edu/abs/1996A&AS..118..481B), [doi](/source/Doi_(identifier)):[10.1051/aas:1996213](https://doi.org/10.1051%2Faas%3A1996213).

v t e Constellation of Lupus List of stars in Lupus Lupus in Chinese astronomy Stars Bayer α (Uridim) β γ δ ε ζ η θ ι κ λ μ ν1 ν2 ξ ο π ρ σ τ1 τ2 υ φ1 φ2 χ ψ1 ψ2 ω Flamsteed 1 (i) 2 (f) Variable RU EX GG GQ HR II IL IM KT (d) V407 V462 HR 5362 5364 5401 5651 (e) 5724 (k) 5825 (g) 5943 5967 HD 134004 135344 136164 141943 142527 143811 Other Gliese 588 HIP 70849 Lupus-TR-3 SSSPM J1549−3544 WASP-132 Exoplanets GQ Lupi b HIP 70849 b Lupus-TR-3b WASP-178b Star clusters NGC 5749 NGC 5822 NGC 5824 NGC 5927 NGC 5986 Nebulae IC 4406 NGC 5882 Galaxies IC 4444 NGC 5530 NGC 5643 Astronomical events SN 1006 Category

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