Sharpless 264, also known as theLambda Orionis Ring, is amolecular cloud andH II region, which can be seen in the northern region of theOrion molecular cloud complex (OMCC), in the constellation ofOrion. The OMCC is one of the best-knownstar formation regions and the closest sector of theMilky Way to theSolar System where high-massstars are born. Thenebula is named after its main star,λ Orionis, ablue giant responsible for theionization of the surrounding material.[1] It is also sometimes called theAngelfish Nebula due to its resemblance as to its lighter areas (pink to peach colour) to anangelfish. In the infrared its ionized boundaries are that which appears, instead.
λ Orionis (also known asMeissa orHeka) at about 1,100 light-years is thestar representing the head ofOrion and can be found to thenorth of the quadrangle defined by the starsBetelgeuse,Bellatrix,Rigel andSaiph. This star can be found at the centre of open clusterCollinder 69 composed of fourth and fifth-magnitude young hot stars, visible to the naked eye. It can be resolved with a pair ofbinoculars. The rest of the cluster and associated nebula spans a few hundred light-years centred about 1400light-years away.
The broad nebula shown is not visible unaided, withbinoculars or small amateurtelescopes. It becomes clear in long-exposurephotographs, such as in the first illustration on this page.
Orange giantφ2 Orionis, while appearing to be surrounded by the Ring, is merely a foreground object at only about 116 light years from Earth.
HD 34989 is ablue-white main sequence star, visible magnified only, just outside the Ring. It has a small nebulous cloud more geared towards the near-infrared than other parts of the neighbouring ionized regions across the Ring.
