Tau-5 Eridani, a blue-white main-sequence star in Eridanus
Tau-5 Eridani is a blue-white main-sequence star in the constellation Eridanus. At 320 light years away, it shines at an apparent visual magnitude of 4.25.
Tau-5 Eridani (HIP 16611)
Tau-5 Eridani is a blue-white main-sequence star in the constellation Eridanus. At 320 light years away, it shines at an apparent visual magnitude of 4.25. It is moving through the Galaxy at a speed of 28.2 km/s relative to the Sun.
Sky position: RA 3h 33.8m, Dec -21° 38.0'
Common designations: Tau-5 Eridani, 19 Eridani, HR 1088, HD 22203, HIP 16611, Gaia DR3 5100353485969674880
Tau-5 Eridani has the spectral type B9V. B-type stars are hot (about 10,000 to 30,000 K), luminous and blue-white. They are massive, short-lived stars, typically only tens of millions of years old, and are common in young clusters and OB associations. Its luminosity class V means it is a main-sequence (dwarf) star, still fusing hydrogen into helium in its core like the Sun.
How to find Tau-5 Eridani in the sky
Tau-5 Eridani lies in Eridanus. With a declination of -21° 38.0', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 68° N. It is bright enough to see with the naked eye under dark skies. It is highest in the sky at local midnight around December, which makes the weeks around that month the best time to observe it.
Tabulated data for Tau-5 Eridani
Astrometry and spectroscopy
| Right Ascension (J2000) | 53.44698288° (3h 33.8m) |
| Declination (J2000) | -21.63288448° (-21° 38.0') |
| Galactic Longitude | 213.52036135° |
| Galactic Latitude | -52.78447433° |
| Proper motion RA | 44.75 mas/yr |
| Proper motion Dec | -27.68 mas/yr |
| Parallax | 10.19 ± 0.18 mas |
| Spectral Type | B9V |
| Radial Velocity | 14.00 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| B | 4.15 | -0.81 |
| V | 4.25 | -0.71 |
| J | 4.52 | -0.44 |
| H | 4.53 | -0.43 |
| K | 4.55 | -0.41 |
Colour index B-V: -0.10
Derivations
- Heliocentric distance: 98.12 pc (320 light years) (1.8% margin of error)
- Absolute visual magnitude: -0.71
- Transverse velocity: 24.5 km/s
- Space velocity relative to the Sun: 28.2 km/s
- Galactic position (X, Y, Z): -49.5 pc, -32.8 pc, -78.1 pc
- Galactic velocity (U, V, W): -7.7 km/s, -27.1 km/s, -1.3 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.