A beautiful image of an unusual planetary nebula has been captured by the European Southern Observatory (ESO)’s Very Large Telescope (VLT). The object, technically known as NGC 2899, is located between 3,000 and 6,500 light-years away in the constellation of Vela (the Sails) and has been imaged in detail for the first time, showing off its rare butterfly shape.
The nebula appears this way because of the glowing gas it is composed of. Despite their name, planetary nebulae are not actually related to planets. Instead, they are clouds of dust and gas which glow because they are illuminated by stars. When these objects were first observed using early telescopes, astronomers thought they looked similar to planets, hence the name. But with newer telescopes, we have been able to image these objects in much more detail and see that they are in fact clouds.
This particular nebula is at a very high temperature, with the hot gas glowing to create the visual effect.
“NGC 2899’s vast swathes of gas extend up to a maximum of two light-years from its center, glowing brightly in front of the stars of the Milky Way as the gas reaches temperatures upwards of 10,000 degrees [Celsius],” ESO scientists explained in a statement. “The high temperatures are due to the large amount of radiation from the nebula’s parent star, which causes the hydrogen gas in the nebula to glow in a reddish halo around the oxygen gas, in blue.”
Astronomers believe that the nebula developed its unusual shape because it has two central stars, which push out and illuminate gas in a symmetrical way. This type of nebula is called bipolar, and only around 10% to 20% of nebulae are of this type.
The image was captured using the FORS instrument on the VLT, standing for FOcal Reducer and low dispersion Spectrograph, which images in the visual and near-ultraviolet light wavelengths.