Mu Boötis

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Mu Boötis
Diagram showing star positions and boundaries of the Boötes constellation and its surroundings
Diagram showing star positions and boundaries of the Boötes constellation and its surroundings

Location of μ Boötis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation
Boötes
A
Right ascension 15h 24m 29.43147s[1]
Declination +37° 22′ 37.7613″[1]
Apparent magnitude (V) 4.31[2]
B or Ba
Right ascension 15h 24m 30.86726s[3]
Declination +37° 20′ 50.2761″[3]
Apparent magnitude (V) 6.98[4]
C or Bb
Right ascension 15h 24m 30.89704s[5]
Declination +37° 20′ 52.555″[5]
Apparent magnitude (V) 7.63[4]
Characteristics
Mu1 Boötis
Spectral type F2IV[6]
U−B color index +0.06[7]
B−V color index +0.31[7]
R−I color index 0.15
Mu2 Boötis
Spectral type F9V + G0V[6]
U−B color index +0.13[7]
B−V color index +0.59[7]
Distance
123 ± 4 ly
(38 ± 1 pc)
Absolute magnitude (MV)1.47[9]
B or Ba
Distance
119.81 ± 0.07 ly
(36.73 ± 0.02 pc)
C or Bb
Distance
119.85 ± 0.08 ly
(36.75 ± 0.02 pc)
Argument of periastron
(ω)
(secondary)		43.5°
Argument of periastron
(ω)
(secondary)		338°
Details
Aa
Rotational velocity (v sin i)
89[6] km/s
Ab
Rotational velocity (v sin i)
40[6] km/s
B or Ba
Gyr
C or Bb
Gyr
HR 5734, SAO
64687
Database references
SIMBADμ1 Boo
μ2 Boo

Mu Boötis, Latinized from μ Boötis, consists of a pair of double stars in the northern constellation of Boötes, 120 light-years from the Sun.

Mu Boötis had the traditional name Alkalurops /ælkəˈljʊərɒps/, although the International Astronomical Union now regards that name as only applying to μ1 Boötis.[11]

System

Mu Bootis (Alkalurops) as seen in a small telescope

The primary pair, component A, is designated μ1 Boötis and the two components an

″.[citation needed
]

The secondary, consisting of components BC, is designated μ2 Boötis and they have a separation of 2.2″. The two double star systems are separated by 107″, with matching parallaxes and

proper motions, suggesting they form a system. However, components BC have a different chemical composition compared to the A pair, indicating this may instead be a close encounter between two binary systems.[6]

Nomenclature

μ Boötis (Latinised to Mu Boötis) is the star's Bayer designation. It also bears the Flamsteed designation 51 Boötis.

The system's traditional name Alkalurops is from the Greek καλαύροψ kalaurops "a herdsman's crook or staff", with the Arabic prefix attached.[12] It has also been known as Inkalunis (from the Alfonsine tables), Clava (Latin 'the club') and Venabulum (Latin 'a hunting spear').[13] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[14] to catalogue and standardize proper names for stars. The WGSN approved the name Alkalurops for μ¹ Boötis on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.[11]

It is known as 七公六, Qī Gōng liù (the Sixth Star of the Seven Excellencies) in Chinese.[15]

Properties

Illustration of Mu1,2 Boötis

μ1 Boötis is a yellow-white F-type subgiant with an apparent magnitude of +4.31.

Separated from its brighter companion by 108

arcseconds.[citation needed
] They complete one orbit about their common centre of mass every 260 years.

References

  1. ^
    S2CID 244398875
    . Gaia DR3 record for this source at VizieR.
  2. ^
    Bibcode:1990A&AS...85.1015M
    .
  3. ^
    S2CID 244398875
    . Gaia DR3 record for this source at VizieR.
  4. ^
    S2CID 119047709
    .
  5. ^
    S2CID 244398875
    . Gaia DR3 record for this source at VizieR.
  6. ^
    S2CID 122667185
    .
  7. ^
    Bibcode:1966CoLPL...4...99J
    .
  8. S2CID 119231169
    .
  9. S2CID 119257644
    .
  10. S2CID 55586789
    .
  11. ^ a b Mamajek, Eric; et al. (June 30, 2017), IAU Catalog of Star Names, IAU Division C Working Group on Star Names, retrieved 28 July 2016.
  12. ISBN 0-486-21079-0, retrieved 2016-09-15 {{citation}}: ISBN / Date incompatibility (help
    )
  13. ISBN 0-486-21079-0, retrieved 2016-09-15. {{citation}}: ISBN / Date incompatibility (help
    )
  14. ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016.
  15. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 26 日 Archived 2011-05-22 at the Wayback Machine
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