The Flaming Star Nebula (IC 405, Caldwell 31 & Sh2-229) is a rippling cloud of gas and dust lying about 1,500 light years away in Auriga, the Charioteer. It is one of the finest imaging targets in the northern sky as a large, attractive and famous nebula that’s both an emission (H-II region) and reflection nebula rolled into one. It can be found and observed through a medium- to large-aperture telescope and has the dual advantage that it’s observable all night and rides high close to the zenith at culmination.
Don’t run from AE Aurigae
The Flaming Star Nebula surrounds the eruptive variable star AE Aurigae (Aur), the ‘flaming star’ that gives the nebula its name and whose torrents of energetic radiation illuminate the nebula. Carbon-rich dust surrounding the nebula reflects the star’s blue light.
AE is what astronomer’s term a ‘runaway star’, massive class- O and -B stars that rocket through space at unusually fast velocities. AE Aur (class-O9) is barreling through interstellar space at a remarkable 200 kilometres per second. Astronomers have tracked AE Aur’s path back 2.5 million years to its origins close the Orion Nebula (M42). They theorise that a close encounter between massive stars, close to where the famous Orion’s Trapezium cluster would later form, caused the ejection of AE Aur and Mu Columbae.
Get your bearings
AE Aur (HIP 24575) varies between around magnitude +5.7 to +6.1, and so it’s an easy binocular object with which to pin-point the nebula’s location. From iota (i) Aur, the westernmost star of Auriga’s ‘hexagonal’ asterism, trace a line to theta (q) Aur on the opposite side of the hexagon. Travel about a third of the way along (by about 4°) and you should alight on AE Aur and the Flaming Star Nebula. It also lies just under 3° south-west of Messier 38, one of Auriga’s great trio of open clusters.
IC 410 next door
The Flaming Star Nebula’s north–south-orientated narrow western arm extends to 1.4°, with its brighter, north-eastern quadrant spanning around the size of a full Moon. To see any wispy nebulosity, you’ll need a fine night and probably the light grasp of a 100–150mm (four- to six-inch) telescope with a widefield eyepiece working at low power – 30x or 40x.
Two degrees south-east of the Flaming Star Nebula is IC 410, an attractive emission nebula and another great imaging target that has the popular title of ‘The Tadpoles’. A small- to medium-aperture telescope will show NGC 1893 to good effect, a very young open cluster formed out of the interstellar cloud that its young stars are now energising.