HD 134687

{{about-distinguish2|e Lupi|[[epsilon Lupi|ε Lupi]]}} {{short description|Binary star system in the constellation of Lupus}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=Lupus constellation map.svg|alt=|float=center|width=250 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=HD 134687 |x=535|y=808 }} | caption = Location of HD 134687 (circled in red) }} {{Starbox observe | epoch = J2000 | constell = [[Lupus (constellation)|Lupus]]<ref name=Anderson2012/> | ra = {{RA|15|12|49.58752}}<ref name=GaiaDR3/> | dec = {{DEC|-44|30|01.4904}}<ref name=GaiaDR3/> | appmag_v = 4.81<ref name=Hohle2010/> }} {{Starbox character | type = [[main sequence]]<ref name=GaiaDR3/> | class = B3 IV/V<ref name=houk1978/> | b-v = {{Val|−0.177|0.011}}<ref name=Anderson2012/> }} {{Starbox astrometry | radial_v = {{Val|+13.5|7.4}}<ref name=deBruijne2012/> | prop_mo_ra = ��21.669<ref name=GaiaDR3/> | prop_mo_dec = −21.895<ref name=GaiaDR3/> | parallax = 7.2373 | p_error = 0.2045 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = −1.11<ref name=Anderson2012/> }} {{Starbox orbit | reference = <ref name=Buscombe1962/> | period_unitless = 0.901407 d | eccentricity = ≤ 0.03 | periastron = 0.366 }} {{Starbox detail | source = | component1 = e Lup A | mass = {{Val|6.0|0.1}}<ref name=Tetzlaff2011/> | radius = 7.1<ref name=cadars/> | luminosity_bolometric = 997<ref name=Hohle2010/> | gravity = | temperature = 17,100<ref name=Hohle2010/> | metal_fe = | rotational_velocity = 13<ref name=Wolff2007/> | age_myr = {{Val|20.3|4.8}} }} {{Starbox catalog | names={{odlist | B=e Lup | CD=-44°9932 | HD=134687 | HIP=74449 | HR=5651 | SAO=225539 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = HD+134687 }} {{Starbox end}}

'''HD 134687''' ('''e Lupi''') is a [[binary star]] system in the southern [[constellation]] [[Lupus (constellation)|Lupus]]. It is visible to the naked eye with an [[apparent visual magnitude]] of 4.81.<ref name=Hohle2010/> The distance to HD 134687 can be estimated from its annual [[stellar parallax|parallax shift]] of {{Val|7.2|ul=mas}},<ref name=GaiaDR3/> yielding roughly 450 [[light year]]s. It is a member of the ~11 million year old Upper Centaurus–Lupus subgroup of the [[Scorpius–Centaurus association]], the closest [[OB association]] to the Sun.<ref name=Chen2012/>

This is a single-lined [[spectroscopic binary]] star system. The pair have a nearly circular orbit with an [[orbital eccentricity|eccentricity]] of at or below 0.03 and a [[orbital period|period]] of {{Convert|0.901407|days|hours}}. The primary has an {{nowrap|''a'' sin ''i''}} value of {{Val|2.735e5|u=km}}, which only gives a lower bound for the [[semimajor axis]] ''a'' since the [[orbital inclination]] ''i'' to the line of sight is unknown.<ref name=Buscombe1962/> The system is a source for [[X-ray astronomy|X-ray emission]].<ref name=Berghoefer1996/>

The visible component has a [[stellar classification]] of B3 IV/V,<ref name=houk1978/> matching a [[B-type star]] showing a [[stellar spectrum|spectrum]] with mixed traits of a [[main sequence]] and a [[subgiant star]]. It is 20 million years old with a [[projected rotational velocity]] of 13 km/s.<ref name=Wolff2007/> The star has 6.0<ref name=Tetzlaff2011/> times the [[mass of the Sun]] and 7.1<ref name=cadars/> times the [[Sun's radius]]. It is radiating 997<ref name=Hohle2010/> times the [[Sun's luminosity]] from its [[photosphere]] at an [[effective temperature]] of 17,100 K.<ref name=Hohle2010/>

==References== <references>

<ref name=SIMBAD>{{cite simbad | title=HD 134687 | access-date=2018-07-22 }}</ref>

<ref name=Buscombe1962>{{citation | title=Two B-Type Spectroscopic Binaries | last1=Buscombe | first1=W. | last2=Kennedy | first2=P. M. | journal=Publications of the Astronomical Society of the Pacific | volume=74 | issue=439 | page=323 | date=August 1962 | doi=10.1086/127818 | bibcode=1962PASP...74..323B | doi-access=free }}</ref>

<ref name=houk1978>{{citation | last1=Houk | first1=Nancy | title=Michigan catalogue of two-dimensional spectral types for the HD stars | volume=2 | publication-place=Ann Arbor | year=1978 | publisher=Dept. of Astronomy, University of Michigan | bibcode=1978mcts.book.....H | postscript=. }}</ref>

<ref name=Chen2012>{{citation | title=A Spitzer MIPS Study of 2.5–2.0 M<sub>☉</sub> Stars in Scorpius–Centaurus | display-authors=1 | last1=Chen | first1=Christine H. | last2=Pecaut | first2=Mark | last3=Mamajek | first3=Eric E. | last4=Su | first4=Kate Y. L. | last5=Bitner | first5=Martin | journal=The Astrophysical Journal | volume=756 | issue=2 | id=133 | pages=24 | date=September 2012 | doi=10.1088/0004-637X/756/2/133 | bibcode=2012ApJ...756..133C | arxiv=1207.3415 | s2cid=119278056 | postscript=. }}</ref>

<ref name=Tetzlaff2011>{{citation | display-authors=1 | last1=Tetzlaff | first1=N. | last2=Neuhäuser | first2=R. | last3=Hohle | first3=M. M. | title=A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume=410 | issue=1 | pages=190–200 |date=January 2011 | doi=10.1111/j.1365-2966.2010.17434.x | doi-access=free | bibcode=2011MNRAS.410..190T | postscript=. | arxiv=1007.4883 | s2cid=118629873 }}</ref>

<ref name=Hohle2010>{{citation | last1=Hohle | first1=M. M. | last2=Neuhäuser | first2=R. | last3=Schutz | first3=B. F. | title=Masses and luminosities of O- and B-type stars and red supergiants | journal=Astronomische Nachrichten | volume=331 | issue=4 | page=349 | date=April 2010 | doi=10.1002/asna.200911355 | bibcode=2010AN....331..349H | arxiv=1003.2335 | s2cid=111387483 | postscript=. }}</ref>

<ref name=Wolff2007>{{citation | last1=Wolff | first1=S. C. | last2=Strom | first2=S. E. | last3=Dror | first3=D. | last4=Venn | first4=K. | title=Rotational Velocities for B0-B3 Stars in Seven Young Clusters: Further Study of the Relationship between Rotation Speed and Density in Star-Forming Regions | journal=[[The Astronomical Journal]] | volume=133 | pages=1092–1103 | date=2007 | issue=3 | doi=10.1086/511002 | bibcode=2007AJ....133.1092W | arxiv=astro-ph/0702133 | s2cid=119074863 | postscript=. }}</ref>

<ref name=cadars>{{citation | display-authors=1 | last1=Pasinetti Fracassini | first1=L. E. | last2=Pastori | first2=L. | last3=Covino | first3=S. | last4=Pozzi | first4=A. | title=Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) | edition=Third | journal=Astronomy and Astrophysics | volume=367 | issue=2 | pages=521–524 | date=February 2001 | doi=10.1051/0004-6361:20000451 | bibcode=2001A&A...367..521P | arxiv=astro-ph/0012289 | s2cid=425754 | postscript=. }}</ref>

<ref name=deBruijne2012>{{citation | last1=de Bruijne | first1=J. H. J. | last2=Eilers | first2=A.-C. | title=Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project | journal=Astronomy & Astrophysics | volume=546 | id=A61 | pages=14 | date=October 2012 | doi=10.1051/0004-6361/201219219 | bibcode=2012A&A...546A..61D | arxiv=1208.3048 | s2cid=59451347 | postscript=. }}</ref>

<ref name=Berghoefer1996>{{citation | title=The ROSAT all-sky survey catalogue of optically bright OB-type stars | last1=Berghoefer | first1=T. W. | last2=Schmitt | first2=J. H. M. M. | last3=Cassinelli | first3=J. P. | journal=Astronomy and Astrophysics Supplement | volume=118 | pages=481–494 | date=September 1996 | issue=3 | doi=10.1051/aas:1996213 | bibcode=1996A&AS..118..481B | postscript=. | doi-access=free }}</ref>

</references>

[[Category:B-type subgiants]] [[Category:Spectroscopic binaries]] [[Category:Lupus (constellation)]] [[Category:Bayer objects|Lupi, e]] [[Category:Durchmusterung objects|CD-44 09932]] [[Category:Henry Draper Catalogue objects|134687]] [[Category:Hipparcos objects|074449]] [[Category:Bright Star Catalogue objects|5651]] [[Category:Upper Centaurus Lupus]]