GW Ori is a system of three stars that are gravitationally bound. Aside from being a triple system, GW Ori also stands out for another reason — it harbors a circumtriple disk, which is a disk of gas and dust surrounding all three stars.
A Tricky Triple
The dust component of GW Ori’s disk as seen by ALMA, showing the three rings discussed in this study. The x- and y-axes of the plot are position offsets, with (0,0) being the position of GW Ori. The color of the rings indicate intensity of emission, with yellow being more intense than purple. The circle in the lower left corner shows the size of the beam used by ALMA to image the disk. [Bi et al. 2020]GW Ori lives in a star cluster called Lambda Orionis, which appears near Betelgeuse on the sky. The inner stars of the system, GW Ori A and GW Ori B, orbit each other and are separated by about 1 astronomical unit (au). The third star, GW Ori C, revolves around its two companions at a distance of roughly 8 au.
GW Ori’s circumtriple disk is enormous relative to the orbits of its stars. The dust component ...