Theta2 Orionis

The spectral type suggests it is evolving away from the main sequence, although it is thought to be less than 2 million years old.

The spectral peculiarities may be related to close companions or could be caused by the extreme youth of the star.

Component C is another B class main sequence star, but cooler and less than a thousand times the luminosity of the sun.

High resolution spectroscopy shows that there is an even closer companion, only about 0.47 AU from the primary, for a total of three stars.

The x-rays cannot be explained standard mechanisms such as colliding winds or coronal emissions from an unseen companion.

The three stars of θ 2 Orionis within the Orion Nebula