Hubble was recently retrained on NGC 6302, known as the "Butterfly Nebula," to observe it across a more complete spectrum of light, from near-ultraviolet to near-infrared, helping researchers better understand the mechanics at work in its technicolor "wings" of gas. The observations highlight a new pattern of near-infrared emission from singly ionized iron, which traces an S-shape from lower left to upper right. This iron emission likely traces the central star system’s most recent ejections of gas, which are moving at much faster speeds than the previously expelled mass. The star or stars at its center are responsible for the nebula's appearance. In their death throes, they have cast off layers of gas periodically over the past couple thousand years. The "wings" of NGC 6302 are regions of gas heated to more than 36,000 degrees Fahrenheit that are tearing across space at more than 600,000 miles an hour. NGC 6302 lies between 2,500 and 3,800 light-years away in the constellation Scorpius.
Credits: NASA, ESA and J. Kastner (RIT)
Imagine a lawn sprinkler spinning wildly, tossing out two S-shaped streams. At first it appears chaotic, but if you stare for a while, you can trace its patterns. The same S-shape is present in the Butterfly Nebula, except in this case it is not water in the air, but gas blown out at high speed by a star. And the "S" only appears when captured by the Hubble camera filter that records near-infrared emission from singly ionized iron atoms.
"The S-shape in the iron emission from the Butterfly Nebula is a real eye-opener," Kastner said. The S-shape directly traces the most recent ejections from the central region, since the collisions within the nebula are particularly violent in these specific regions of NGC 6302. "This iron emission is a sensitive tracer of energetic collisions between slower winds and fast winds from the stars," Balick explained. "It's commonly observed in supernova remnants and active galactic nuclei, and outflowing jets from newborn stars, but is very rarely seen in planetary nebulas."
"The fact that the iron emission is only showing up along these opposing, off-center directions implies that the source of the fast flows is wobbling over time, like a spinning top that's about to fall," added Kastner. "That's another tell-tale sign of the presence of a disk, which directs the flow, and also a binary companion."
Source: Hubble Provides A View of Stars Gone Haywire