Chandra Release - November 12, 2015

Visual Description: Delta Orionis

One of the most recognizable constellations in the sky is Orion, the Hunter. Among Orion's best-known features is the "belt," consisting of three bright stars in a line, each of which can be seen without a telescope.  At the center of the main panel, which is an image from an optical telescope, there are three bright blue stars in a line (Orion's "belt") that stands out due to their intense luminosity. These stars are surrounded by a cluster of smaller, dimmer stars, which appear as white dots in the image. In the lower right corner of the image, there is another bright blue star that shines brightly against the dark backdrop of space, and a smaller one at lower left and upper right as well.  There is also a bright orange star at upper left, finishing off the Orion constellation.  In the upper right corner of the image, there is an inset of a pinkish-purple speckly source, which resembles a spattered paint ball.  This is the X-ray image.  The westernmost star in Orion's belt is known officially as Delta Orionis. (Since it has been observed for centuries by sky-watchers around the world, it also goes by many other names in various cultures, like "Mintaka".) Modern astronomers know that Delta Orionis is not simply one single star, but rather it is a complex multiple star system. By observing this eclipsing binary component of Delta Orionis A (dubbed Delta Ori Aa) with NASA's Chandra X-ray Observatory for the equivalent of nearly six days, a team of researchers gleaned important information about massive stars and how their winds play a role in their evolution and affect their surroundings. The Chandra image in the inset box is in context with an optical view of the Orion constellation obtained from a ground-based telescope.