With the remarkable observation ability of NASA’s James Webb Space Telescope, astronomers have been able to discern the details of the planetary nebula NGC 1514, including a dying star within it. This level of insight was previously impossible before the service of this telescope.
In a press release issued by NASA on April 14th, it was pointed out that with the mid-infrared data from the Webb Space Telescope, astronomers were able to focus entirely on the gas and dust being expelled by the dying star at the center of the planetary nebula NGC 1514. The nebula’s ring structure can only be detected in infrared light.
Mike Ressler, a researcher and project scientist of the Mid-Infrared Instrument (MIRI) at NASA’s Jet Propulsion Laboratory, stated, “Before the Webb Space Telescope, we couldn’t detect most of this material, let alone observe them so clearly.”
Ressler discovered the halo surrounding NGC 1514 in images captured by NASA’s Wide-field Infrared Survey Explorer (WISE) in 2010.
“With the data from MIRI, we can now comprehensively study the complex characteristics of this nebula,” he said.
The scene within NGC 1514 has evolved for at least 4,000 years and is expected to continue changing over the next few thousand years. The nebula’s center hosts two stars, one of which had a mass several times that of the Sun and played a dominant role in the formation of the scene.
David Jones, a senior scientist at the Canary Islands Institute of Astrophysics in Spain, explained that as this star evolves, it will gradually expand, releasing layers of gas and dust into an extremely slow and dense stellar wind.
Once the star’s outer layers are shed, only its hot, dense core remains. As a white dwarf star, its stellar wind will accelerate and weaken, possibly enveloping its matter in a thin outer shell.
Observations from the Webb Space Telescope reveal that NGC 1514 is tilted at a 60-degree angle, resembling a tilted jar, with a shape more likely resembling an hourglass with its ends cut off.
In NASA’s released images, the dust near the upper left and lower right corners of the nebula appears orange and drifts into a shallow V-shape.
How were these structures formed? Jones explained, “When the material being ejected by this star reaches its peak, the companion star may come very, very close. This interaction can create unexpected shapes. Interactions like these can form ring structures rather than spheres.”
In NASA’s images, the brightness of the two ring structures in NGC 1514 is uneven, appearing more blurry in the lower left and upper right corners.
Ressler mentioned that these ring structures are primarily composed of extremely small dust grains. “When these grains are exposed to the ultraviolet radiation from the white dwarf star, they slightly heat up, which we believe makes their temperature just enough to be detected by the Webb Space Telescope in mid-infrared light.”
Aside from dust, the Webb Space Telescope also discovered oxygen at the center of the nebula but did not detect carbon and its more complex forms, known as polycyclic aromatic hydrocarbons.
Due to the orbital paths of the two stars at the nebula’s center mixing up the expelled materials, more complex molecules may not have had enough time to form. The presence of simpler components also means that the light emitted by these stars can reach further distances, which explains why blurry cloud-like halos are visible.
NGC 1514 is located in the constellation Taurus at a distance of approximately 1,500 light-years from Earth. Astronomers have been studying this planetary nebula since the late 18th century. Now with the Webb Space Telescope, their observations of this phenomenon have become much clearer.