{{Short description|Star in the constellation Boötes}} {{Starbox begin}} {{Starbox image | image = [[Image:EKBooLightCurve.png|250px]] | caption = The [[Photometric_system#Photometric_letters|visual band]] [[light curve]] of EK Boötes, from AAVSO data<ref name="aavso"/> }} {{Starbox observe | epoch = J2000 | ra = {{RA|14|46|05.94566}}<ref name="van Leeuwen2007"/> | dec = {{DEC|+15|07|54.4332}}<ref name="van Leeuwen2007"/> | appmag_v = 5.33 to 5.71<ref name=Samus2017/> | constell = [[Boötes]] }} {{Starbox character | type = | class = M5III<ref name=aa524_A57/> | b-v = {{val|1.335|0.021}}<ref name=Anderson_Francis_2012/> | u-b = +1.26<ref name="MERMILLIOD"/> | variable = [[Slow irregular variable|Lb?]]<ref name=Samus2017/>
}} {{Starbox astrometry | radial_v = {{val|−22.52|0.65}}<ref name="Famaey2009"/> | prop_mo_ra = −85.49<ref name="van Leeuwen2007"/> | prop_mo_dec = +18.86<ref name="van Leeuwen2007"/> | parallax = 4.04 | p_error = 0.38 | parallax_footnote = <ref name="van Leeuwen2007"/> | absmag_v = −1.17<ref name=Anderson_Francis_2012/> }} {{Starbox detail | mass = {{val|3.1|0.5}}<ref name=aa524_A57/> | radius = {{val|210|21}}<ref name=aa524_A57/> | luminosity = 521.51<ref name=Anderson_Francis_2012/> | temperature = 3,400<ref name=aa524_A57/> | metal_fe = | gravity = | rotational_velocity = 8.5 or 11<ref name=aa524_A57/> | age_gyr = }} {{Starbox catalog | names = {{odlist | V=EK Boo | BD=+15°2758 | FK5=3168 | HD=130144 | HIP=72208 | HR=5512 | SAO=101200 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = EK+Boo }} {{Starbox end}}
'''HD 130144''' is a [[variable star]] in the northern [[constellation]] of [[Boötes (constellation)|Boötes]]. It has the [[variable star designation]] '''EK Boötis''' (or EK Boo), while ''HD 130144'' is the designation from the ''[[Henry Draper Catalogue]]''. The star is faintly visible to the [[naked eye]] with an [[apparent visual magnitude]] that ranges from 5.33 down to 5.71.<ref name=Samus2017/> [[Stellar parallax|Parallax]] measurements provide a distance estimate of approximately 810 [[light year]]s from the [[Sun]]. It is drifting closer with a [[radial velocity]] of −23 km/s.<ref name="Famaey2009"/>
The brightness of HD 130144 was discovered to be variable when the ''[[Hipparcos]]'' satellite data was analyzed. It was given its variable star designation in 1999.<ref name="Kazarovets1999"/> This is an aging [[red giant star]] with a [[stellar classification]] of M5III.<ref name=aa524_A57/> It has an estimated 3.1 times the [[mass of the Sun]] and has expanded to around 210 times the [[Sun's radius]].<ref name=aa524_A57/> EK Boo is classified as a [[slow irregular variable]] that ranges in luminosity with an amplitude of 0.38 in magnitude and no apparent periodicity. This is an [[X-ray astronomy|X-ray source]], and was possibly the first M-type giant star to have a [[Stellar magnetic field|magnetic field]] directly detected.<ref name=Georgiev_et_al_2020/> The strength of the field ranges from –0.1 to {{val|8|ul=G}}.<ref name=Renada_et_al_2009/>
HD 130144 has a high rotation rate for a star of this class, which may be the result of [[dredge-up]] of [[angular momentum]] from the interior, or else a merger with an orbiting companion.<ref name=Renada_et_al_2009/> A long-term trend in the radial velocity data suggests this star has an orbiting companion. Most likely this is an active [[red dwarf]] that is responsible for most of the X-ray emission from the system.<ref name=Georgiev_et_al_2020/> There is nearby [[visual companion]] at an angular separation of {{val|0.20|ul=arcsecond}} along a [[position angle]] of 82.2° (as of 2010).<ref name=Horch2011/>
==References== <references> <ref name="aavso">{{cite web |title=Download Data |url=https://www.aavso.org/data-download |website=aavso.org |publisher=AAVSO |access-date=1 October 2021}}</ref>
<ref name=SIMBAD>{{cite simbad | title=EK Boo | access-date=2021-04-30 | mode=cs2 | postscript=. }}</ref>
<ref name="Kazarovets1999">{{cite journal | last1=Kazarovets | first1=E. V. | last2=Samus | first2=N. N. | last3=Durlevich | first3=O. V. | last4=Frolov | first4=M. S. | last5=Antipin | first5=S. V. | last6=Kireeva | first6=N. N. | last7=Pastukhova | first7=E. N. | bibcode=1999IBVS.4659....1K | title=The 74th Special Name-list of Variable Stars | journal=Information Bulletin on Variable Stars | date=January 1999 | volume=4659 | pages=1–27 | url=https://ibvs.konkoly.hu/pub/ibvs/4601/4659.pdf | access-date=6 December 2024}}</ref>
<ref name=Georgiev_et_al_2020>{{citation | title=Magnetism in Cool Evolved Stars: the M giants EK Bootis and β Pegasi | last1=Georgiev | first1=S. | last2=Konstantinova-Antova | first2=R. | last3=Lèbre | first3=A. | last4=Aurière | first4=M. | last5=Charbonnel | first5=C. | last6=Palacios | first6=A. | last7=Drake | first7=N. | last8=Bogdanovski | first8=R. | display-authors=1 | journal=Bulgarian Astronomical Journal | volume=33 | page=87 | date=July 2020 | bibcode=2020BlgAJ..33...87G | postscript=. }}</ref>
<ref name=Anderson_Francis_2012>{{citation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | title=XHIP: An extended hipparcos compilation | journal=Astronomy Letters | postscript=. | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | arxiv=1108.4971 | doi=10.1134/S1063773712050015 | s2cid=119257644 }}</ref>
<ref name="van Leeuwen2007">{{citation | first=F. | last=van Leeuwen | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | postscript=. | volume=474 | issue=2 | pages=653–664 | date=November 2007 | bibcode=2007A&A...474..653V | s2cid=18759600 | doi=10.1051/0004-6361:20078357 | arxiv=0708.1752 }}</ref>
<ref name=Samus2017>{{citation | postscript=. | display-authors=1 | last1=Samus | first1=N. N. | last2=Kazarovets | first2=E. V. | last3=Durlevich | first3=O. V. | last4=Kireeva | first4=N. N. | last5=Pastukhova | first5=E. N. | title=General Catalogue of Variable Stars | version=5.1 | journal=[[Astronomy Reports]] | year=2017 | volume=61 | issue=1 | pages=80–88 | bibcode=2017ARep...61...80S | s2cid=125853869 | doi=10.1134/S1063772917010085 }}</ref>
<ref name=Renada_et_al_2009>{{citation | title=Dynamo-generated magnetic fields in fast rotating single giants | first1=Renada | last1=Konstantinova-Antova | first2=Michel | last2=Aurière | first3=Klaus-Peter | last3=Schröder | first4=Pascal | last4=Petit | work=Cosmic Magnetic Fields: From Planets, to Stars and Galaxies, Proceedings of the International Astronomical Union, IAU Symposium | volume=259 | pages=433–434 | date=April 2009 | issue=S259 | doi=10.1017/S1743921309031020 | arxiv=0901.1537 | bibcode=2009IAUS..259..433K | s2cid=119199670 }}</ref>
<ref name="Famaey2009">{{citation | title=Spectroscopic binaries among Hipparcos M giants,. I. Data, orbits, and intrinsic variations | display-authors=1 | last1=Famaey | first1=B. | last2=Pourbaix | first2=D. | last3=Frankowski | first3=A. | last4=Van Eck | first4=S. | last5=Mayor | first5=M. | last6=Udry | first6=S. | last7=Jorissen | first7=H. A. | journal=Astronomy and Astrophysics | postscript=. | volume=498 | issue=2 | pages=627–640 | year=2009 | arxiv=0901.0934 | bibcode=2009A&A...498..627F | doi=10.1051/0004-6361/200810698 | s2cid=18739721 }}</ref>
<ref name="MERMILLIOD">{{citation | last1=Mermilliod | first1=J.-C. | postscript=. | title=Compilation of Eggen's UBV data, transformed to UBV (unpublished) | journal=Catalogue of Eggen's UBV Data. SIMBAD | date=1986 | bibcode=1986EgUBV........0M }}</ref>
<ref name=Horch2011>{{citation | title=Observations of Binary Stars with the Differential Speckle Survey Instrument. II. Hipparcos Stars Observed in 2010 January and June | display-authors=1 | last1=Horch | first1=Elliott P. | last2=Gomez | first2=Shamilia C. | last3=Sherry | first3=William H. | last4=Howell | first4=Steve B. | last5=Ciardi | first5=David R. | last6=Anderson | first6=Lisa M. | last7=van Altena | first7=William F. | journal=The Astronomical Journal | postscript=. | volume=141 | issue=2 | id=45 | pages=13 | date=February 2011 | doi=10.1088/0004-6256/141/2/45 | bibcode=2011AJ....141...45H | s2cid=27904496 | url=http://authors.library.caltech.edu/22553/1/Horch2011p12763Astron_J.pdf }}</ref>
<ref name=aa524_A57>{{citation | title=Direct detection of a magnetic field in the photosphere of the single M giant EK Bootis. How common is magnetic activity among M giants? | display-authors=1 | last1=Konstantinova-Antova | first1=R. | last2=Aurière | first2=M. | last3=Charbonnel | first3=C. | last4=Drake | first4=N. A. | last5=Schröder | first5=K.-P. | last6=Stateva | first6=I. | last7=Alecian | first7=E. | last8=Petit | first8=P. | last9=Cabanac | first9=R. | journal=Astronomy and Astrophysics | postscript=. | volume=524 | id=A57 | pages=9 | date=December 2010 | doi=10.1051/0004-6361/201014503 | arxiv=1009.2001 | bibcode=2010A&A...524A..57K | s2cid=119184105 }}</ref> </references>
==External links== * [http://webviz.u-strasbg.fr/viz-bin/VizieR-S?HR%205512 HR 5512] * [http://aladin.u-strasbg.fr/AladinPreview?-c=14+46+05.9459%2B15+07+54.436&ident=V*+EK+Boo&submit=Aladin+previewer Image HD 130144]
{{Stars of Boötes}}
[[Category:M-type giants]] [[Category:Slow irregular variables]] [[Category:Red dwarfs]] [[Category:Binary stars]] [[Category:Boötes]] [[Category:Durchmusterung objects]] [[Category:Henry Draper Catalogue objects|130144]] [[Category:Hipparcos objects|072208]] [[Category:Bright Star Catalogue objects|5512]] [[Category:Objects with variable star designations|Boötis, EK]]