Star with a known planet

alf Tau

alf Tau, a K5 III star, has one confirmed planet.

Measured

Distance
about 66.6 light-years
Star's spectral type
K5 III
Confirmed planets
1

How far, from the Sun

About 66.6 light-years. To cross it:

  • Light66.6 years
  • Voyager 1's speed1.18 million years
  • Driving at 100 km/h719 million years

Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.

How it was found

  • First planet found in 2015, by radial velocity (NASA Exoplanet Archive).

Its planets

  • alf Tau b — 13 times Earth's width (estimated from its mass, not measured), a giant, Jupiter-sized or more; its year lasts 630 days; about 810 °C, hotter than boiling water; found in 2015 by radial velocity.

The NASA Exoplanet Archive's page

Where this comes from

  • NASA Exoplanet Archive, Planetary Systems Composite Parameters (fetched 2026-11-02). Composite values: where a planet's size or mass was not measured, the archive estimates it from the other.
  • This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program.

Every catalogue Ouranos draws is credited on the credits page.