Mu Librae
Star in the constellation Libra
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μ Librae (Latinised as Mu Librae) is a probable triple star[3] system in the zodiac constellation of Libra. They have a combined apparent visual magnitude of 5.32,[2] which is bright enough to be faintly visible to the naked eye. With an annual parallax shift of 13.71 mas,[1] the system is located at an estimated distance of around 240 light years.
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Libra |
| Right ascension | 14h 49m 19.05130s[1] |
| Declination | −14° 08′ 56.4766″[1] |
| Apparent magnitude (V) | 5.32[2] (5.69 + 6.72[3] + 14.70[4]) |
| Characteristics | |
| Spectral type | A1pSrCrEu + A6m[3] |
| B−V color index | +0.07[2] |
| Astrometry | |
| Radial velocity (Rv) | −3.2±1.4[5] km/s |
| Proper motion (μ) | RA: −65.95[1] mas/yr Dec.: −14.54[1] mas/yr |
| Parallax (π) | 13.71±0.69 mas[1] |
| Distance | 240 ± 10 ly (73 ± 4 pc) |
| Absolute magnitude (MV) | 1.32±0.20[6] |
| Details | |
| μ Lib A | |
| Mass | 2.31±0.12[7] M☉ |
| Radius | 2.59[8] R☉ |
| Luminosity | 41.7[7] L☉ |
| Temperature | 9,592±260[7] K |
| Rotational velocity (v sin i) | 29.0±1.7[7] km/s |
| Age | 417[6] Myr |
| μ Lib B | |
| Radius | 2.59[8] R☉ |
| Rotational velocity (v sin i) | 32.0±6[8] km/s |
| Other designations | |
| μ Lib, BD−13°3986, HD 130559, HIP 72489, HR 5523, SAO 158821[9] | |
| Database references | |
| SIMBAD | data |
The inner pair consists of two A-type stars that, as of 2006, had an angular separation of 1.79 arc seconds along a position angle of 5.5°.[10] They have an estimated physical separation of 139 AU.[8] The primary, component A, is a visual magnitude 5.69[3] magnetic Ap star showing overabundances of the elements aluminum, strontium, chromium, and europium.[7] Hence, it has a stellar classification of A1pSrEuCr.[3] It is a photometric variable with periods of 25.3992±0.1970 d and 1.8871±0.0008 d. The surface magnetic field strength is 1,375 Gauss.[7]
The secondary, component B, is an Am star with a stellar classification of A6m.[3] It has a visual magnitude of 6.72.[3] The tertiary member, component C, is a magnitude 14.70 star at an angular separation of 12.90 arc seconds along a position angle of 294°, as of 2000.[4]