τ Orionis (tau Orionis)
τ Orionis is a multiple giant star in the constellation of Orion.
τ Orionis visual magnitude is 3.6. Because of its moderate brightness, τ Orionis should be easily visible from locations with dark skyes, while it can be barely visible, or not visible at all, from skyes affected by light pollution.
The table below summarizes the key facts about τ Orionis:
Celestial coordinates and finder chart of τ Orionis
τ Orionis is situated close to the celestial equator, as such, it is at least partly visible from both hemispheres in certain times of the year. Celestial coordinates for the J2000 equinox as well as galactic coordinates of τ Orionis are provided in the following table:
The simplified sky map below shows the position of τ Orionis in the sky:
Visibility of τ Orionis from your location
Digitized Sky Survey image of τ Orionis
The image below is a photograph of τ Orionis from the Digitized Sky Survey 2 (DSS2 - see the credits section) taken in the red channel. The area of sky represented in the image is 0.5x0.5 degrees (30x30 arcmins). The proper motion of τ Orionis is -0.015 arcsec per year in Right Ascension and -0.008 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.
Distance of τ Orionis from the Sun and relative movement
τ Orionis is distant 554.42 light years from the Sun and it is moving far from the Sun at the speed of 20 kilometers per second.
Spectral properties of τ Orionis
τ Orionis belongs to spectral class B5 and has a luminosity class of III corresponding to a giant star.
The red dot in the diagram below shows where τ Orionis is situated in the Hertzsprung–Russell diagram.
τ Orionis star system properties
τ Orionis is a visual double star which can be observed only with the help of very large telescopes. The table below shows key information about the τ Orionis double sysyem: