Webb reveals more than one star contributes to the irregular shape of planetary nebula NGC 6072

Lisa Lock
scientific editor

Andrew Zinin
lead editor

Since the discovery of planetary nebulae in the late 1700s, astronomers have learned that these expanding shells of glowing gas expelled by low-intermediate mass stars late in their lives can come in all shapes and sizes. Most planetary nebulae present as circular, elliptical, or bi-polar, but some stray from the norm, as seen in new high-resolution images of the planetary nebula NGC 6072 by the NASA/ESA/CSA James Webb Space Telescope.
In Webb's NIRCam (Near-Infrared Camera) view of the object, it's readily apparent that this nebula is multi-polar. This means there are several different elliptical outflows jetting out either way from the center. These outflows compress gas towards the equatorial plane and create a disk. Astronomers say this is evidence that there are likely at least two stars at the center of this scene. Specifically, a companion star is interacting with an aging star that had already begun to shed some of its outer layers of gas and dust.
The central region of the planetary nebula glows from the hot stellar core, seen as a light blue hue in near-infrared light. The dark orange material, which is made up of gas and dust, follows pockets or open areas that appear dark blue. This clumpiness could be created when dense molecules formed while being shielded from hot radiation from the central star. There could also be a time element at play. Over thousands of years, inner fast winds could be plowing through the halo cast off from the main star when it first started to lose mass.
The longer wavelengths captured by Webb's MIRI (Mid-Infrared Instrument) are highlighting dust, revealing the star researchers suspect could be central to this scene. It appears as a small pink-white dot in this image. Webb's look in the mid-infrared wavelength also reveals concentric rings expanding from the central region, the most obvious circling just past the edges of the lobes.
This may be additional evidence of a secondary star at the center of the scene hidden from our view. The secondary star, as it circles repeatedly around the original star, could have carved out rings of material in a spiral pattern as the main star was expelling mass during an earlier stage of its life.

The red areas in NIRCam and blue areas in MIRI both trace cool molecular gas (likely molecular hydrogen) while central regions trace hot ionized gas.
Planetary nebulae will remain a topic of study for astronomers using Webb who hope to learn more about the full life cycle of stars and how they impact their surrounding environments. As the star at the center of a planetary nebula cools and fades, the nebula will gradually dissipate into the interstellar medium—contributing enriched material that helps form new stars and planetary systems, now containing those heavier elements.
Webb's imaging of NGC 6072 opens the door to studying how the planetary nebulae with more complex shapes contribute to this process.
Provided by European Space Agency