tau Boo is 51.0 light-years from the Sun. The NASA Exoplanet Archive lists 1 planet around this F7 V star; the first was found in 1996 by radial velocity (Lick Observatory).
Fly there in 3Dtau Boo b goes round its star every 3.31 days, 27 times as often as Mercury goes round the Sun.
tau Boo is one of 2 stars in its system: the other is drawn where the Washington Double Star Catalog measures it on the sky.
| Spectral type | F7 V |
| Surface temperature | 6,466 K |
| Mass | 1.32 solar masses |
| Radius | 1.42588 solar radii |
| Luminosity | 3.202 times the Sun |
| Apparent magnitude | 4.48635 |
| Age | about 2 billion years |
| Distance from the Sun | 51.0 light-years (15.7 parsecs) |
| Position (J2000) | RA 206.8135°, Dec 17.4572° |
| Constellation | Boötes |
tau Boo B is a M2V star of magnitude 11.1, with a computed orbit. In 2017 it was 1.5″ from tau Boo, at position angle 76° (Washington Double Star Catalog, 13473+1727 STT 270 AB): 23.5 AU on the sky at this distance. The true distance can only be larger.
| Planet | Year | Orbit | Radius | Mass | Found |
|---|---|---|---|---|---|
| tau Boo b | 3.31 days | 0.0490 AU | 12.8 R⊕ estimated | 1891 M⊕ | Radial Velocity, 1996 |
Values are the NASA Exoplanet Archive’s composite parameters. A radius marked estimated comes from a mass–radius relation; a mass marked minimum is M sin i. Planet sizes and colours in the 3D view are renderings: none of these worlds has been photographed as more than a point of light.
For a star of 6,466 K, 3.2 times as bright as the Sun, the habitable zone, where starlight could keep water liquid on a rocky surface, runs from about 1.63 to 2.84 AU. None of its known planets orbits inside it. The zone says how much starlight arrives, not whether a planet has water or air. The edges follow Kopparapu et al. (2014), as the 3D view draws them.
The light you see left 51 years ago, within living memory.