  | |
| Observation data EpochJ2000.0 EquinoxJ2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 04h 45m 30.15038s[1] |
| Declination | −03° 15′ 16.7765″[1] |
| Apparent magnitude (V) | 4.00[2] |
| Characteristics | |
| Spectral type | B5 IV[3] |
| U−Bcolor index | −0.60[2] |
| B−Vcolor index | −0.15[2] |
| Variable type | SPB andAlgol[4] |
| Astrometry | |
| Proper motion (μ) | RA: +0.25[1]mas/yr Dec.: −1.97[1]mas/yr |
| Parallax (π) | 6.25±0.19 mas[1] |
| Distance | 520 ± 20 ly (160 ± 5 pc) |
| Absolute magnitude (MV) | −2.06±0.07[5] |
| Orbit[5] | |
| Period (P) | 7.38090 d |
| Eccentricity (e) | 0.344±0.021 |
| Periastronepoch (T) | 2455143.254±0.067 HJD |
| Argument of periastron (ω) (secondary) | 160.5±4.5° |
| Semi-amplitude (K1) (primary) | 0.344±0.021 km/s |
| Details | |
| μ Eri A | |
| Mass | 6.2±0.2[5] M☉ |
| Radius | 6.1[4] R☉ |
| Luminosity | 1,905[4] L☉ |
| Surface gravity (log g) | 3.5[5] cgs |
| Temperature | 15,668[4] K |
| Metallicity[Fe/H] | 0[5] dex |
| Rotational velocity (v sin i) | 130±3[4] km/s |
| Other designations | |
| μ Eri,BD−03°876,57 Eridani,FK5 176,HD 30211,HIP 22109,HR 1520,SAO 131468[6] | |
| Database references | |
| SIMBAD | data |
Mu Eridani (μ Eridani) is abinary star system in theconstellationEridanus. It is visible to thenaked eye with anapparent visual magnitude of 4.00.[2] Based upon an annualparallax shift of 0.00625 arcseconds,[1] it is located roughly 520 light years from theSun.
In 1910, this was determined to be a single-linedspectroscopic binary star system. The pair orbit each other with aperiod of 7.38 days and aneccentricity of 0.344, during which they undergoAlgol-like eclipses.[5] The primary is aslowly pulsating B-type star[4] with astellar classification of B5 IV.[3] Additionally, the variability of the star's brightness due to pulsations was first detected by Gerald Handleret al. in 2004.[7] One year later, Mikołaj Jerzykiewiczet al. announced that eclipses had been detected.[8] It has a relatively high rate of rotation with aprojected rotational velocity of 130 km/s, which is at least 30% of the star'sbreak-up velocity.[4] The star has about six times the Sun's mass and radius, and it shines with 1,905 times thesolar luminosity from itsouter atmosphere at aneffective temperature of 15,668 K.[5][4]
