Kappa Librae

{{Starbox begin

| name = Kappa Librae

}}

{{Starbox observe

| epoch = J2000.0

| equinox = J2000.0 (ICRS)

| constell = Libra

| ra = {{RA|15|41|56.79858}}

| dec = {{DEC|−19|40|43.7745}}

| appmag_v = 4.72

}}

{{Starbox character

| class = K5 III

| b-v = +1.58

| u-b = +1.94

| r-i =

| variable =

}}

{{Starbox astrometry

| radial_v = {{Val|−4.5|1.5}}

| prop_mo_ra = −32.06

| prop_mo_dec = −103.15

| parallax = 10.57

| p_error = 1.40

| parallax_footnote =

| absmag_v = −0.62

}}

{{Starbox detail

| source =

| mass =

| radius = 38

| luminosity = 296

| temperature = 3,930

| gravity =

| metal_fe =

| rotational_velocity =

| age_myr =

}}

{{Starbox catalog

| names = {{odlist | B=κ Lib | F=43 Lib | BD=−19° 4188 | FK5=1413 | HD=139997 | HIP=76880 | HR=5838 | SAO=159442 }}

}}

{{Starbox reference

| Simbad = kap+Lib

}}

Kappa Librae, Latinized from κ Librae, is the Bayer designation for a star system in the zodiac constellation of Libra. Its apparent visual magnitude is 4.72, so it can be seen with the naked eye. The annual parallax shift of 10.57 mas indicates it is roughly 310 light years away. It is positioned 0.02 degrees south of the ecliptic.

The star shows acceleration components in its proper motion, indicating with high probability that it is an astrometric binary. The visible component is an evolved K-type giant star with a stellar classification of K5 III. It is a suspected variable star with a brightness that ranges between 4.70 and 4.75. The measured angular diameter is {{Val|3.71|0.10|u=mas}}, which, at the estimated distance of Kappa Librae, yields a physical size of about 38 times the radius of the Sun. It radiates 296 times the solar luminosity from its outer atmosphere at an effective temperature of 3,930 K.

In Chinese astronomy, Kappa Librae is called 日, Pinyin: Rì, meaning Sun, because this star is marking itself and stand alone in Sun asterism, Room mansion (see : Chinese constellation).[http://www.ianridpath.com/startales/libra.htm#chinese Ian Ridpath's Startales - Libra the Scales]

References

{{reflist|2|refs=

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| arxiv=0708.1752 | bibcode=2007A&A...474..653V

| doi=10.1051/0004-6361:20078357 | s2cid=18759600 | postscript=. }}

{{citation

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| bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015

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| display-authors=etal | date=2004 | postscript=.

| title=Combined General Catalogue of Variable Stars (GCVS4.2)

| journal=Vizier Online Data Catalog | bibcode=2004yCat.2250....0S }}

{{citation

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| journal=The Astronomical Journal | postscript=.

| volume=129 | issue=5 | pages=2420–2427 | date=May 2005

| doi=10.1086/429590 | bibcode=2005AJ....129.2420M | url=https://apps.dtic.mil/sti/pdfs/ADA433654.pdf| archive-url=https://web.archive.org/web/20170924050424/http://www.dtic.mil/get-tr-doc/pdf?AD=ADA433654| url-status=live| archive-date=September 24, 2017| doi-access=free }}

{{citation

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| title=CHARM2: An updated Catalog of High Angular Resolution Measurements

| journal=Astronomy and Astrophysics | postscript=.

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| issue=2 | doi=10.1051/0004-6361:20042039 | bibcode=2005A&A...431..773R | doi-access=free }}

{{citation

| first1=Kenneth R. | last1=Lang

| title=Astrophysical formulae | volume=1

| series=Astronomy and astrophysics library

| edition=3rd | publisher=Birkhäuser

| date=2006 | isbn=3-540-29692-1

| url=https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41

}}. The radius (R_*) is given by:

: $\begin{align} 2\cdot R_*
& = \frac{(94.6\cdot 3.71\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\
& \approx 75.5\cdot R_{\bigodot}
\end{align}$

{{citation

| display-authors=1 | last1=McDonald | first1=I.

| last2=Zijlstra | first2=A. A. | last3=Boyer | first3=M. L.

| title=Fundamental Parameters and Infrared Excesses of Hipparcos Stars

| journal=Monthly Notices of the Royal Astronomical Society

| volume=427 | issue=1 | pages=343–57 | date=2012

| bibcode=2012MNRAS.427..343M | arxiv=1208.2037

| doi=10.1111/j.1365-2966.2012.21873.x | doi-access=free | s2cid=118665352 | postscript=. }}

{{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