The brilliant “butterfly wings” of the PN M2-9 Nebula

Image credit: NASA/ESA/Hubble

This new image taken by the Hubble Space Telescope shows the impressive complexity of the PN M2-9 Nebula, also known as the Twin Jets Nebula. The image highlights in great detail two iridescent lobes stretching outward from a central star system. Inside these lobes, two huge jets of gas shoot out at speeds in excess of a million kilometers per hour.

The M in the name of the PN M2-9 Nebula refers to Rudolph Minkowski, an astronomer who discovered the nebula in 1947. The PN refers to the fact that M2-9 is a planetary nebula. The huge bulges of gas visible in the image represent the end-of-life stage of an old, low-mass star. The outer layers that have been expelled by the star are being illuminated by the remaining core that has been exposed, resulting in an impressive light show. However, the PN M2-9 Nebula is not only a planetary nebula, it is also a bipolar nebula.

Normally planetary nebulae contain only one star in the center, while bipolar nebulae have two, that is, they are a binary star system. Astronomers have discovered that each of the stars in the PN M2-9 Nebula has a mass similar to that of the Sun: the smallest has 0.6 to 1.0 the mass of the Sun while the largest has 1 0 to 1.4 the mass of the Sun. The largest star is near the end of its life and has already expelled its outer layers into space, while its companion is a white dwarf star.

The prominent wing shape of the PN M2-9 Nebula was created due to the rotation of the two central stars as they orbit each other. The rotation also causes the gas ejected from the dying star to concentrate in two lobes, instead of expanding into a uniform sphere. The wings are known to continue to grow, and by measuring the expansion, astronomers have calculated that the nebula was created 1,200 years ago.