:zeta Boötis
{{short description|Triple star in the constellation Boötes}}
{{Starbox begin
| name = ζ Boötis
}}
{{Starbox image
| image =
{{Location mark
| image=Boötes IAU.svg | alt= | float=center | width=250
| label= | position=right
| mark=Red circle.svg | mark_width=10 | mark_link=ζ Boötis
| x%=45.0 | y%=71.0
}}
| caption = Location of ζ Boötis (circled)
}}
{{Starbox observe 2s
| epoch = J2000
| constell = Boötes
| component1 = ζ Boo
| dec1 = {{DEC|+13|43|41.8967}}
| appmag_v1 = 3.78 {{nowrap|(4.46 + 4.55)}}
| component2 = HIP 71759
| dec2 = {{DEC|+13|32|03.5621}}
}}
{{Starbox character
| component1 = ζ Boo
| type =
| variable =
| component2 = HIP 71759
| variable2 = δ Scuti
}}
{{Starbox astrometry
| component1 = ζ Boo
| prop_mo_ra = +51.95
| prop_mo_dec = −11.08
| parallax = 18.56
| p_error = 0.76
| component2 = HIP 71759
| prop_mo_ra2 = +54.399
| prop_mo_dec2 = −15.481
| parallax2 = 19.3257
| p_error2 = 0.0511
}}
{{Starbox visbin
| primary = ζ Boo A
| name = ζ Boo B
| period_unitless = {{val|125.04|0.24|0.21|fmt=commas}} years
| axis_unitless = {{val|41.84|0.46|0.44|ul=au}}
| eccentricity = 0.98045
| inclination = {{val|125.88|0.16}}
| periarg = {{val|62.08|0.13|0.14}}
| node = {{val|176.63|0.16}}
| periastron = 2023.9548
}}
{{Starbox detail
| component1 = ζ Boo A
| mass = {{val|2.21|0.14|0.05}}
| radius = {{Val|2.6|0.3|0.4}}
| temperature = {{Val|8800|1000|600|fmt=commas}}
| age_myr = {{val|560|150|240}}
| component2 = ζ Boo B
| mass2 = {{Val|2.15|0.10|0.03}}
| radius2 = {{val|2.4|0.3}}
| temperature2= {{Val|8750|800|550|fmt=commas}}
| age_myr2 = {{val|560|150|240}}
}}
{{Starbox detail|no_heading=y
| component1 = HIP 71759
| luminosity = {{val|9.01|0.22}}
| temperature = {{val|7660|107|fmt=commas}}
}}
{{Starbox catalog
| names={{odlist | B=ζ Boo | F=30 Boötis | BD=+14°2770 | HIP=71795 | SAO=101145 | ADS=9343 | CCDM=14411+1344 | GC=19777 | WDS=J14411+1344 }}
| component1 = A
| names1 = {{odlist | HD=129247 | HR=5478 }}
| component2 = B
| names2 = {{odlist | HD=129246 | HR=5477 }}
| component3 = HIP 71759
| names3 = {{odlist|HD=129153|BD=+14 2769|HR=5473|SAO=101137|TIC=119613557|TYC=917-1472-1}}
}}
{{Starbox reference
| Simbad = zet+Boo
}}
{{Starbox reference|no_heading=y
| component = HIP 71759
| Simbad = HIP+71759
}}
{{Starbox end}}
Zeta Boötis is a triple star system in the constellation of Boötes. Its name is a Bayer designation that is Latinized from ζ Boötis, and abbreviated Zeta Boo or ζ Boo.
They have the Flamsteed designation 30 Boötis. This system is visible to the naked eye as a point of light with an apparent visual magnitude of +3.78. The individual magnitudes of the components differ slightly, with component A having a magnitude of 4.46 and component B at the slightly dimmer magnitude 4.55. The system is located at a distance of approximately 180 light years based on parallax, but is drifting closer to the Sun with a radial velocity of −9 km/s.
Observations
The duplicity of this star was discovered by English astronomer William Herschel in 1796, and their changing positions have been tracked from 1823 onward.
In 1976, T. W. Edwards found a stellar classification of A2III for both inner components, suggesting they may be evolved A-type giant stars. Helmut A. Abt reported a class of A2V in 1981, which matches an A-type main-sequence star. Abt and Nidia Morrell updated the classification to A1V in 1995.
Characteristics
The two components of the inner pair, Zeta Boötis A and B, are A-type main-sequence stars. Component A has 2.21 times the Sun's mass, 2.6 times the Sun's radius and an effective temperature of 8,800 K. Component B has 2.15 times the Sun's mass, 2.4 times the Sun's radius and an effective temperature of 8,750 K. Their estimated age is 560 million years.
The stars take 125 years to orbit each other. The orbit of this pair has a very high eccentricity of 0.98045, bringing them within 0.818 au at their closest approach (periastron). {{asof|2025}}, the eccentricity of this system is possibly the second-highest known, after HIP 26245, whose eccentricity is {{Val|0.985|0.002}}. The last periastron occurred during November 2023. Considering the extreme nature of their orbit, it is unlikely that any exoplanets could have stable orbits around either star.
Together with the star HIP 71759, Zeta Boötis make a triple star system. This distant star has an estimated orbital period of three million years, being at an observed distance of {{cvt|41300|au|e9km ly}} from the inner pair. The orbit of this star is likely what forced the high eccentricity orbit of the inner pair, via the Kozai mechanism. It has a class of F0V, matching an F-type main-sequence star. It is a Delta Scuti variable with a brightness amplitude of 0.00134 magnitudes.
Gallery
Image:zboo lucky image 1pc.png|Zeta Bootis imaged with the Nordic Optical Telescope on 13 May 2000 using the lucky imaging method. (The Airy discs around the stars is diffraction from the 2.56m telescope aperture.)
Image:Zeta bootis short exposure.png|Typical short-exposure image of a binary star, as seen using speckle imaging through the Earth's atmosphere.
References
{{reflist|refs=
{{cite simbad | title=zet Boo | access-date=2020-12-31 }}
{{cite simbad | title=zet Boo A | access-date=2020-12-31 }}
{{cite simbad | title=zet Boo B | access-date=2020-12-31 }}
| title=The Phases Differential Astrometry Data Archive. III. Limits to Tertiary Companions
| display-authors=1 | last1=Muterspaugh | first1=Matthew W.
| last2=Lane | first2=Benjamin F. | last3=Kulkarni | first3=S. R.
| last4=Konacki | first4=Maciej | last5=Burke | first5=Bernard F.
| last6=Colavita | first6=M. M. | last7=Shao | first7=M.
| journal=The Astronomical Journal | postscript=.
| volume=140 | issue=6 | pages=1631–1645 | date=December 2010
| arxiv=1010.4044 | bibcode=2010AJ....140.1631M
| doi=10.1088/0004-6256/140/6/1631 | s2cid=9272936 }}
| title=Hidden Companions to Intermediate-mass Stars. XVI. Unveiling a 41,300 au Companion to the Very Eccentric Binary Zeta Boötis
| display-authors=1 | last1=Waisberg | first1=Idel
| last2=Klein | first2=Ygal | last3=Katz | first3=Boaz
| journal=Research Notes of the AAS | language=en
| volume=8 | issue=3 | pages=55 | date=March 2024
| doi=10.3847/2515-5172/ad2df5 | doi-access=free
| bibcode=2024RNAAS...8...55W | issn=2515-5172 }}
| title=The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars
| last1=Abt | first1=Helmut A. | last2=Morrell | first2=Nidia I.
| journal=Astrophysical Journal Supplement
| volume=99 | page=135 | date=July 1995 | postscript=.
| bibcode=1995ApJS...99..135A | doi=10.1086/192182 | doi-access=free }}
| title=Orbites des étoiles doubles
| last=Wierzbiński | first=St.
| journal=Acta Astronomica | postscript=.
| volume=6 | page=82 | date=1956
| bibcode=1956AcA.....6...82W }}
{{cite DR3|1179640088134099456}}
| title=Visual multiples. VII. MK classifications
| last1=Abt | first1=H. A. | postscript=.
| journal=The Astrophysical Journal Supplement Series
| volume=45 | pages=437 | year=1981
| bibcode=1981ApJS...45..437A | doi=10.1086/190719 }}
| title=The Washington Visual Double Star Catalog
| display-authors=1 | last1=Mason | first1=B. D.
| last2=Wycoff | first2=G. L. | last3=Hartkopf | first3=W. I.
| last4=Douglass | first4=G. G. | last5=Worley | first5=C. E.
| journal=The Astronomical Journal
| volume=122 | issue=6 | pages=3466–3471 | year=2014
| bibcode=2001AJ....122.3466M | postscript=.
| doi=10.1086/323920 | doi-access=free }}
| title=Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system
| last1=Gontcharov | first1=G. A.
| journal=Astronomy Letters | postscript=.
| volume=32 | issue=11 | pages=759–771 | year=2006
| bibcode=2006AstL...32..759G | arxiv=1606.08053
| doi=10.1134/S1063773706110065 | s2cid=119231169 }}
| first=F. | last=van Leeuwen | date=November 2007
| title=Validation of the new Hipparcos reduction
| journal=Astronomy and Astrophysics
| volume=474 | issue=2 | pages=653–664
| bibcode=2007A&A...474..653V | arxiv=0708.1752
| doi=10.1051/0004-6361:20078357 | s2cid=18759600 }}
| 71795 | mode=cs2 | postscript=.}}
| last=Nicolet | first=B. | postscript=.
| title=Photoelectric photometric Catalogue of homogeneous measurements in the UBV System
| journal=Astronomy and Astrophysics Supplement Series
| volume=34 | pages=1–49 | year=1978
| bibcode=1978A&AS...34....1N }}
| title=A study of the bright A stars. I. A catalogue of spectral classifications
| last1=Cowley | first1=A. | last2=Cowley | first2=C.
| last3=Jaschek | first3=M. | last4=Jaschek | first4=C.
| display-authors=1 | journal=Astronomical Journal
| volume=74 | pages=375–406 | date=April 1969
| doi=10.1086/110819 | bibcode=1969AJ.....74..375C }}
}}
External links
- {{citation | first=James B. | last=Kaler | title=ZETA BOO (Zeta Bootis) | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/zetaboo.html | access-date=2011-12-18 }}
- [http://webviz.u-strasbg.fr/viz-bin/VizieR-S?HR%205477 HR 5477]
- [http://aladin.u-strasbg.fr/AladinPreview?-c=14+41+08.5%2B13+43+42&ident=HD+129246&submit=Aladin+previewer Image Zeta Boötis]
- [http://webviz.u-strasbg.fr/viz-bin/VizieR-S?CCDM%20J14411%2b1344B CCDM J14411+1344]
{{Stars of Boötes}}
{{DEFAULTSORT:Zeta Bootis}}
Category:A-type main-sequence stars