Mu1 Boötis
Binary star in the northern constellation of Boötes
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Mu1 Boötis is a binary star in the northern constellation of Boötes. Its name is a Bayer designation that is Latinized from μ1 Boötis, and abbreviated Mu1 Boo or μ1 Boo. This system had the traditional name Alkalurops, pronounced /ælkəˈljʊərɒps/.[8] Based on parallax measurements, the system is located at a distance of 123 light-years.
  Location of μ1 Boötis (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 15h 24m 29.43147s[1] |
| Declination | +37° 22′ 37.7613″[1] |
| Apparent magnitude (V) | 4.31[2] |
| Characteristics | |
| Spectral type | F2IV[3] |
| U−B color index | +0.06[4] |
| B−V color index | +0.31[4] |
| R−I color index | 0.15 |
| Astrometry | |
| Radial velocity (Rv) | −8.60±0.3[5] 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[6] |
| Orbit[3] | |
| Primary | Aa |
| Name | Ab |
| Period (P) | 3.75 years |
| 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° |
| Details | |
| Aa | |
| Mass | 1.6[3] M☉ |
| Radius | 1.9[2] R☉ |
| Luminosity | 20[7] L☉ |
| Surface gravity (log g) | 3.4[3] cgs |
| Temperature | 7,000[3] K |
| Rotational velocity (v sin i) | 89[3] km/s |
| Ab | |
| Mass | 1.5[3] M☉ |
| Surface gravity (log g) | 3.6[3] cgs |
| Temperature | 7,000[3] K |
| Rotational velocity (v sin i) | 40[3] km/s |
| Other designations | |
| Alkalurops, Inkalunis, Icalurus, Clava, Venabulum, μ Boo, 51 Boötis A, BD+37°2636, FK5 568, GC 20724, GJ 3903, HD 137391, HIP 75411, HR 5733, SAO 64686, ADS 9626, CCDM 15245+3722 | |
| Database references | |
| SIMBAD | data |
The components of the system have an angular separation of 0.10″.[9] They form a spectroscopic binary system with an orbital period of 3.75 years.[3] The visible component is a yellow-white F-type subgiant with an apparent magnitude of +4.31.
The system μ2 Boötis, separated by 109", makes an optical double with μ1, and even has a similar distance from Earth and comparable proper motions, but has a substantially different metallicity, and therefore is not a gravitationally bound companion.[3]
Nomenclature
μ1 Boötis (Latinised to Mu1 Boötis) is the star's Bayer designation.
The system's traditional name Alkalurops is from the Greek καλαύροψ kalaurops "a herdsman's crook or staff", with the Arabic prefix attached.[10] It has also been known as Inkalunis (from the Alfonsine tables), Clava (Latin 'the club') and Venabulum (Latin 'a hunting spear').[11] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[12] 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.[8]
It is known as 七公六, Qī Gōng liù (the Sixth Star of the Seven Excellencies) in Chinese.[13]
Gallery
Mu Bootis (Alkalurops) as seen in a small telescope
Illustration of Mu1,2 Boötis
