Mu2 Boötis
Location of μ2 Boötis (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes |
| A | |
| Right ascension | 15h 24m 30.86726s |
| Declination | +37° 20′ 50.2761″ |
| Apparent magnitude (V) | 6.98 |
| B | |
| Right ascension | 15h 24m 30.89704s |
| Declination | +37° 20′ 52.5550″ |
| Apparent magnitude (V) | 7.63 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | F9V + G0V |
| U−B color index | +0.13 |
| B−V color index | +0.59 |
| Astrometry | |
| A | |
| Proper motion (μ) | RA: −139.142 mas/yr Dec.: +90.281 mas/yr |
| Parallax (π) | 27.2223±0.0168 mas |
| Distance | 119.81 ± 0.07 ly (36.73 ± 0.02 pc) |
| B | |
| Proper motion (μ) | RA: −152.149 mas/yr Dec.: +89.593 mas/yr |
| Parallax (π) | 27.2126±0.0181 mas |
| Distance | 119.85 ± 0.08 ly (36.75 ± 0.02 pc) |
| Orbit | |
| Primary | A |
| Name | B |
| 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 | |
| A | |
| Mass | 1.24 M☉ |
| Radius | 1.23 R☉ |
| Luminosity | 1.75 L☉ |
| Surface gravity (log g) | 4.3 cgs |
| Temperature | 6,000 K |
| Rotational velocity (v sin i) | 5 km/s |
| Age | 5.6 Gyr |
| B | |
| Mass | 1.05 M☉ |
| Radius | 1.09 R☉ |
| Luminosity | 1.06 L☉ |
| Surface gravity (log g) | 4.4 cgs |
| Temperature | 5,900 K |
| Rotational velocity (v sin i) | 9 km/s |
| Age | 11.3 Gyr |
| Other designations | |
| 51 Boo B, BD+37°2637, GC 20725, GJ 3904, HD 137392, HIP 75415, HR 5734, SAO 64687 | |
| Database references | |
| SIMBAD | data |
Mu2 Boötis is a binary star in the northern constellation of Boötes. Its name is a Bayer designation that is Latinized from μ2 Boötis, and abbreviated Mu2 Boo or μ2 Boo. Based on parallax measurements, these stars are located at a distance of approximately 120 light-years from the Sun.
The components of μ2 Boötis have apparent magnitudes of +7.0 and +7.6. They have similar spectral types, F9V and G0V respectively, and complete one orbit about their common centre of mass every 260 years.
The system μ1 Boötis is at a similar distance and share similar proper motions with μ2, but has a significantly different chemical composition, so they are not gravitationally bound.