Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
---|---|
Constellation | Eridanus |
Right ascension | 03h 33m 47.27613s [1] |
Declination | −21° 37′ 58.3830″ [1] |
Apparent magnitude (V) | 4.26 [2] |
Characteristics | |
Spectral type | B0 V + B9 V [3] |
U−B color index | 0.35 [2] |
B−V color index | −0.09 [2] |
Astrometry | |
Proper motion (μ) |
RA: +44.94
[1]
mas/
yr Dec.: −28.16 [1] mas/ yr |
Parallax (π) | 11.12 ± 0.21 mas [1] |
Distance | 293 ± 6
ly (90 ± 2 pc) |
Absolute magnitude (MV) | −0.51 [4] |
Orbit [5] | |
Period (P) | 6.2236 d |
Eccentricity (e) | 0.2 |
Periastron epoch (T) | 2424446.548 JD |
Argument of periastron (ω) (secondary) | 313° |
Semi-amplitude (K1) (primary) | 107 km/s |
Semi-amplitude (K2) (secondary) | 103 km/s |
Details | |
τ5 Eri A | |
Mass | 3.30+0.24 −0.20 [6] M☉ |
Radius | 3.2 [3] R☉ |
Luminosity | 188 [7] L☉ |
Surface gravity (log g) | 4.00±0.15 [6] cgs |
Temperature | 12,514±425 [8] K |
Rotational velocity (v sin i) | 55±8 [3] km/s |
Age | 157+23 −45 [6] Myr |
τ5 Eri B | |
Radius | 2.6 [3] R☉ |
Rotational velocity (v sin i) | 50±8 [3] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Tau5 Eridani, Latinized from τ5 Eridani, is a binary star system in the constellation Eridanus. It is visible to the naked eye with a combined apparent visual magnitude of 4.26. [2] The distance to this system, as estimated using the parallax technique, is around 293 light years. [1]
Tau5 Eridani is a double-lined spectroscopic binary system. [10] The two stars orbit each other closely with a period of 6.2 days and an eccentricity of 0.2. [5] On average, the two stars are separated by around 0.183 AU. [3]
The primary component is a B-type main sequence star with a stellar classification of B0 V. [3] It is around 157 million years old and is spinning with a projected rotational velocity of 55 km/s. [3] The star has around 3.3 [6] times the mass of the Sun and 3.2 [3] times the Sun's radius. It radiates 188 [7] times the solar luminosity from an outer atmosphere at an effective temperature of 12,514 K. [8]
The secondary component has a stellar classification of B9 V. [3] It is slightly smaller, with an estimated size equal to 2.6 times the radius of the Sun. [3]
Although τ5 Eridani has no bright visual companion stars, the galaxy IC 1953 is less than 10' away. It is one of the brighter members of a loose group of galaxies called the Eridanus Group scattered around the components of τ Eridani.
Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
---|---|
Constellation | Eridanus |
Right ascension | 03h 33m 47.27613s [1] |
Declination | −21° 37′ 58.3830″ [1] |
Apparent magnitude (V) | 4.26 [2] |
Characteristics | |
Spectral type | B0 V + B9 V [3] |
U−B color index | 0.35 [2] |
B−V color index | −0.09 [2] |
Astrometry | |
Proper motion (μ) |
RA: +44.94
[1]
mas/
yr Dec.: −28.16 [1] mas/ yr |
Parallax (π) | 11.12 ± 0.21 mas [1] |
Distance | 293 ± 6
ly (90 ± 2 pc) |
Absolute magnitude (MV) | −0.51 [4] |
Orbit [5] | |
Period (P) | 6.2236 d |
Eccentricity (e) | 0.2 |
Periastron epoch (T) | 2424446.548 JD |
Argument of periastron (ω) (secondary) | 313° |
Semi-amplitude (K1) (primary) | 107 km/s |
Semi-amplitude (K2) (secondary) | 103 km/s |
Details | |
τ5 Eri A | |
Mass | 3.30+0.24 −0.20 [6] M☉ |
Radius | 3.2 [3] R☉ |
Luminosity | 188 [7] L☉ |
Surface gravity (log g) | 4.00±0.15 [6] cgs |
Temperature | 12,514±425 [8] K |
Rotational velocity (v sin i) | 55±8 [3] km/s |
Age | 157+23 −45 [6] Myr |
τ5 Eri B | |
Radius | 2.6 [3] R☉ |
Rotational velocity (v sin i) | 50±8 [3] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Tau5 Eridani, Latinized from τ5 Eridani, is a binary star system in the constellation Eridanus. It is visible to the naked eye with a combined apparent visual magnitude of 4.26. [2] The distance to this system, as estimated using the parallax technique, is around 293 light years. [1]
Tau5 Eridani is a double-lined spectroscopic binary system. [10] The two stars orbit each other closely with a period of 6.2 days and an eccentricity of 0.2. [5] On average, the two stars are separated by around 0.183 AU. [3]
The primary component is a B-type main sequence star with a stellar classification of B0 V. [3] It is around 157 million years old and is spinning with a projected rotational velocity of 55 km/s. [3] The star has around 3.3 [6] times the mass of the Sun and 3.2 [3] times the Sun's radius. It radiates 188 [7] times the solar luminosity from an outer atmosphere at an effective temperature of 12,514 K. [8]
The secondary component has a stellar classification of B9 V. [3] It is slightly smaller, with an estimated size equal to 2.6 times the radius of the Sun. [3]
Although τ5 Eridani has no bright visual companion stars, the galaxy IC 1953 is less than 10' away. It is one of the brighter members of a loose group of galaxies called the Eridanus Group scattered around the components of τ Eridani.