* Astronomy

T Orionis (T Ori / BD-05 1329 / GCRV 3447) is a star system in the constellation of Orion with an apparent magnitude +11.25. The AAVSO International Database shows T Orionis with a visual range of magnitude 9.3-~12.6.

It is approximately 1500 light years from the Solar System.

T Orionis has spectral type A3 and is a Herbig Ae star. These are pre-main sequence stars that are in a growth phase, incorporating foreign material. They are extremely young stars; with an age of about 4 million years and an uncertain temperature of 9750 K - 8500 K. It has a mass 2.4 times that of the Sun and is between 50 and 83 times more luminous. It rotates with a speed of at least 175 ± 14 km/s. Its metallicity - relative abundance of elements heavier than helium - is similar to the Sun.

T Orionis is a visual binary system with a companion separated by 7.7 arcsec. In turn, T Orionis itself is a spectroscopic binary whose binary nature is known by the Doppler shift of the spectral lines. The two components of this binary are of spectral type A2. T Orionis is a Orion Variable whose luminosity variations are irregular with wild day-to-day variations. Short period variability showed nothing periodic or quasiperiodic.

Position (2000): RA 05 35 50.44 Dec  -05º 28 '34.9''