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.
  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] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | −8.60±0.3[8] km/s |
| Proper motion (μ) | RA: −149.928[1] mas/yr Dec.: +89.573[1] mas/yr |
| Parallax (π) | 26.5759 ± 0.7871 mas[1] |
| Distance | 123 ± 4 ly (38 ± 1 pc) |
| Absolute magnitude (MV) | 1.47[9] |
| B or Ba | |
| Proper motion (μ) | RA: −139.142[3] mas/yr Dec.: +90.281[3] mas/yr |
| Parallax (π) | 27.2223 ± 0.0168 mas[3] |
| Distance | 119.81 ± 0.07 ly (36.73 ± 0.02 pc) |
| C or Bb | |
| Proper motion (μ) | RA: −152.149[5] mas/yr Dec.: +89.593[5] mas/yr |
| Parallax (π) | 27.2126 ± 0.0181 mas[5] |
| Distance | 119.85 ± 0.08 ly (36.75 ± 0.02 pc) |
| Orbit[6] | |
| Primary | Aa |
| Companion | Ab |
| Period (P) | 3.75 yr |
| Semi-major axis (a) | 0.099″ |
| Eccentricity (e) | 0.270 |
| Inclination (i) | 129.7° |
| Longitude of the node (Ω) | 129.4° |
| Periastron epoch (T) | 1006.33 |
| Argument of periastron (ω) (secondary) | 43.5° |
| Orbit[6] | |
| Primary | B |
| Companion | C |
| Period (P) | 265 yr |
| Semi-major axis (a) | 1.46″ |
| Eccentricity (e) | 0.585 |
| Inclination (i) | 135.5° |
| Longitude of the node (Ω) | 174° |
| Periastron epoch (T) | 1864.9 |
| Argument of periastron (ω) (secondary) | 338° |
| Details | |
| Aa | |
| Mass | 1.6[6] M☉ |
| Radius | 1.9[2] R☉ |
| Luminosity | 20[10] L☉ |
| Surface gravity (log g) | 3.4[6] cgs |
| Temperature | 7,000[6] K |
| Rotational velocity (v sin i) | 89[6] km/s |
| Ab | |
| Mass | 1.5[6] M☉ |
| Surface gravity (log g) | 3.6[6] cgs |
| Temperature | 7,000[6] K |
| Rotational velocity (v sin i) | 40[6] km/s |
| B or Ba | |
| Mass | 1.24[6] M☉ |
| Radius | 1.23[3] R☉ |
| Luminosity | 1.75[3] L☉ |
| Surface gravity (log g) | 4.3[6] cgs |
| Temperature | 6,000[6] K |
| Rotational velocity (v sin i) | 5[6] km/s |
| Age | 5.6[3] Gyr |
| C or Bb | |
| Mass | 1.05[6] M☉ |
| Radius | 1.09[5] R☉ |
| Luminosity | 1.06[5] L☉ |
| Surface gravity (log g) | 4.4[6] cgs |
| Temperature | 5,900[6] K |
| Rotational velocity (v sin i) | 9[6] km/s |
| Age | 11.3[5] Gyr |
| Other designations | |
| μ1 Boo: BD+37°2636, GC 20724, GJ 3903, HD 137391, HIP 75411, HR 5733, SAO 64686 | |
| μ2 Boo: BD+37°2637, GC 20725, GJ 3904, HD 137392, HIP 75415, HR 5734, SAO 64687 | |
| Database references | |
| SIMBAD | μ1 Boo |
| μ2 Boo | |
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
edit
The primary pair, component A, is designated μ1 Boötis and the two components an angular separation of 0.08″.[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
editμ 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
edit
μ1 Boötis is a yellow-white F-type subgiant with an apparent magnitude of +4.31.
Separated from its brighter companion by 108 arcseconds in the sky is the binary star μ2 Boötis, which has a combined spectral type of G1V and a combined brightness of +6.51 magnitudes. The components of μ2 Boötis have apparent magnitudes of +7.2 and +7.8 and are separated by 2.2 arcseconds.[citation needed] They complete one orbit about their common centre of mass every 260 years.
References
edit- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b Malagnini, M. L.; Morossi, C. (November 1990), "Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars", Astronomy and Astrophysics Supplement Series, 85 (3): 1015–1019, Bibcode:1990A&AS...85.1015M.
- ^ a b c d e f g h Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b Tokovinin, Andrei (2018-03-01), "The Updated Multiple Star Catalog", The Astrophysical Journal Supplement Series, 235 (1): 6, arXiv:1712.04750, Bibcode:2018ApJS..235....6T, doi:10.3847/1538-4365/aaa1a5, ISSN 0067-0049, S2CID 119047709.
- ^ a b c d e f g h Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d e f g h i j k l m n o p q r s t u Kiyaeva, O. V.; et al. (November 2014), "The multiple system ADS 9626: A quadruple star or an encounter of two binaries?", Astronomy Reports, 58 (11): 835–848, Bibcode:2014ARep...58..835K, doi:10.1134/S106377291411002X, S2CID 122667185.
- ^ a b c d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
- ^ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
- ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
- ^ 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.
- ^ Allen, Richard H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York: Dover Publications Inc, p. 97, ISBN 0-486-21079-0, retrieved 2016-09-15
- ^ Allen, Richard H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York: Dover Publications Inc, p. 105, ISBN 0-486-21079-0, retrieved 2016-09-15.
- ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016.
- ^ (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