Meissa (Lambda Orionis) is a binary star in the constellation Orion consisting of a hot (35,000 K) and luminous (65,000 solar luminosities) O star, of about 25 solar masses located 4 arcseconds away from a B star (25,000 K, 5,500 solar luminosities). Meissa (also known as Hatya) is best-known for a huge surrounding ring of gas, called Sh2-264 or the Meissa Ring, an astonishing 150 light-years across that is ionized by the star. Sh2-264 is itself set within an even larger ring of interstellar dust and molecules. These structures may be composed of material left over from the formation of Meissa that has been compressed by the action of the O star. Alternatively, it's possible they were created from the blast of another star that exploded in the neighborhood of Meissa a few million years ago.