The James Webb Space Telescope (JWST) of the National Aeronautics and Space Administration (NASA) boasts exceptional observation capabilities. With the assistance of this telescope, astronomers have observed the varied appearances of planetary nebulae, which aid in understanding the entire lifecycle of stars and how they impact their surrounding environments.
Planetary nebulae are shells of glowing gas expelled by low to medium mass stars in their late stages of life. Since their discovery in the late 18th century, astronomers have learned that planetary nebulae can exhibit various shapes and sizes.
While most planetary nebulae appear circular, elliptical, or bipolar, there are also some with non-conventional shapes, such as the newly captured image of the planetary nebula NGC 6072 by the James Webb Space Telescope.
The JWST’s Near Infrared Camera (NIRCAM) and Mid-Infrared Instrument (MIRI) captured images of this planetary nebula in the Scorpius constellation in the near-infrared and mid-infrared bands, revealing a splattered paint-like appearance.
This unusual asymmetric appearance implies that more complex mechanisms are at play, as the star at the center of the image is nearing the end of its life, continuously shedding its outer shell and losing up to 80% of its mass.
From the images captured by NIRCAM, it is evident that NGC 6072 is a multipolar planetary nebula. This indicates that several different elliptical outflows are jetting out from the center in various directions. For example, one outflow jets from the 11 o’clock direction to the 5 o’clock direction. These outflows may compress material as they flow, potentially forming a disk perpendicular to them.
Astronomers state that this suggests there are likely at least two stars at the center of this planetary nebula, with one aging star already shedding part of its outer gas and dust, interacting with a companion star.
The central region of this planetary nebula emits light due to the hot stellar core, appearing pale blue in the near-infrared, while the deep orange material composed of gas and dust flows along the dark blue gaps or open regions.
Images taken by MIRI, with longer wavelengths, emphasize the dust. Researchers speculate that the star at the center of this planetary nebula appears as a small white dot in the image.
This image also reveals concentric rings spreading from the central region, with the most prominent ring slightly exceeding the edges of the petal-like structure. This could be additional evidence of another star hidden from our view at the center of this planetary nebula.
This companion star may be in its early stages of life, orbiting the primary star repeatedly, cutting out concentric circular material as the primary star ejects matter. These ring-like structures may also suggest some pulsation causing gas or dust to be uniformly ejected in various directions with intervals of approximately thousands of years.
The red regions in the NIRCam image and the blue regions in the MIRI image trace to cooler molecular gases (likely hydrogen molecules), while the central region traces to hotter ionized gases.
As the star at the center of NGC 6072 cools and gradually dims, its nebula will disperse into the interstellar medium, contributing rich material to form new stars and planetary systems.
The images captured by the James Webb Space Telescope of NGC 6072 have opened the door to studying how more complex-shaped planetary nebulae participate in this process.