The vast space between stars, composed of glowing gas and obscured dust, evokes the image of a bird for astronomers on Earth, earning the name "Seagull Nebula." The bird's large and wide portrait stretches across approximately 3.5 degrees toward Sirius along the plane of the Milky Way. Sirius is the alpha star of Canis Major.
The bright head of the Seagull Nebula is classified as "IC 2177," which is a compact and dusty emission-reflection nebula. The large emission region is likely part of an extensive shell structure swept away by a continuous series of supernova explosions.
The prominent blue arc located below and to the right of the nebula's center is the bow shock of the runaway star "FN Canis Majoris." This complex collection of interstellar gas and dust clouds is dominated by the reddish light of atomic hydrogen. It occupies about 200 light-years, along with other stars belonging to the Canis Major OB1 association, surpassing the estimated distance of the Seagull Nebula, which is 3,800 light-years.