Astrophysical Enigma: Deciphering the Ring Nebula Through Webb’s Advanced Optics

The James Webb Space TelescopeThe James Webb Space Telescope (JWST or Webb) is an orbiting infrared observatory that will complement and extend the discoveries of the Hubble Space Telescope. It covers longer wavelengths of light, with greatly improved sensitivity, allowing it to see inside dust clouds where stars and planetary systems are forming today as well as looking further back in time to observe the first galaxies that formed in the early universe.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>James Webb Space Telescope‘s new images of the Ring Nebula have revealed features suggesting the presence of a companion star and insights into stellar evolution.

The James Webb Space Telescope (JWST) has recorded breathtaking new images of the iconic Ring Nebula, one of the best-known planetary nebulae. Those images were publicly released by an international team of astronomers, which includes Griet Van de Steene and Peter van Hoof, researchers of the Royal Observatory of Belgium. In a research paper, the team presents and analyses features revealed by those images, one of which suggests the presence of a star companion that may contribute to shaping the Ring Nebula into its elliptic form.

Introducing the Ring Nebula

Approximately 2,200 light-years away from Earth, the Ring Nebula is a well-known object that is located in the constellation Lyra. It can be observed all summer long with binoculars on a dark night sky in the northern hemisphere and much of the southern. A small telescope will already reveal the characteristic donut-like structure of glowing gas that gave the Ring Nebula its name. It is a planetary nebula, which is the colorful remnants of dying stars that have thrown out much of their mass at the end of their lives.

The Ring Nebula’s distinctive structure and its vibrant colors have long captivated the human imagination. Stunning visuals of the nebula captured by Webb’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument) instruments were publicly released recently, and offer an opportunity for the public to admire this cosmic marvel and the scientists to study and understand the complex processes that shaped it.

NASA’s James Webb Space Telescope has observed the well-known Ring Nebula in unprecedented detail. Formed by a star throwing off its outer layers as it runs out of fuel, the Ring Nebula is an archetypal planetary nebula. This new image from Webb’s NIRCam (Near-Infrared Camera) shows intricate details of the filament structure of the inner ring. There are some 20,000 dense globules in the nebula, which are rich in molecular hydrogen. In contrast, the inner region shows very hot gas. The main shell contains a thin ring of enhanced emission from carbon-based molecules known as polycyclic aromatic hydrocarbons (PAHs). Credit: ESA/Webb, NASA, CSA, M. Barlow (University College London), N. Cox (ACRI-ST), R. Wesson (Cardiff University)

Detailed Insights From the Webb Images

The new images not only display details of the nebula’s expanding shells but also the inner region around the central white dwarfA white dwarf star is the remnant of star that has exhausted its nuclear fuel, but it lacks the mass to become a neutron star. A typical white dwarf is only slightly bigger than Earth, yet it is 200,000 times as dense.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>white dwarf with clarity. In a paper published in arXiV, 2023, a team of scientists, which includes Griet Van de Steene and Peter van Hoof of the Royal Observatory of Belgium, described and analyzed Ring Nebula’s features revealed by these images.

The authors show that the ‘ring’ of the nebula is composed of about 20,000 individual clumps of dense hydrogen gas globules, each of them about as massive as the Earth. They also detected polycyclic aromatic hydrocarbon (PAH) inside it. This is known as one of the building materials required for the earliest form of life, a thing that we would not expect to form in the Ring Nebula.

Conclusions and Future Studies

The Webb images also showed curious ‘spikes’ outside the ring pointing directly away from the central star. These are prominent in the infrared but were only very faintly visible in Hubble Space TelescopeThe Hubble Space Telescope (often referred to as Hubble or HST) is one of NASA's Great Observatories and was launched into low Earth orbit in 1990. It is one of the largest and most versatile space telescopes in use and features a 2.4-meter mirror and four main instruments that observe in the ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum. It was named after astronomer Edwin Hubble.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Hubble Space Telescope images. The researchers think these could be due to molecules that can form in the shadows of the densest parts of the ring, where they are shielded from the direct, intense radiation from the hot central star.

Finally, the authors discover in the faint halo outside the ring ten concentric arcs. They think that those arcs suggest the presence of a companion star in the system, orbiting about as far away from the central star as PlutoPluto is a dwarf planet in the Kuiper belt, a ring of bodies beyond Neptune. Discovered by American astronomer Clyde Tombaugh in 1930, it was originally considered the ninth planet from the Sun. Its status as a planet was questioned after other similar size objects were discovered in the Kuiper belt, and in 2006 the International Astronomical Union (IAU) officially reclassified it as a dwarf planet.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Pluto does from our Sun and sculpting the Nebula to its form that may be otherwise spherical.

The never-before-seen details of Webb images provide a wealth of new scientific insights into the processes of stellar evolution. By studying the Ring Nebula with the James Webb Space Telescope, scientists hope to gain a deeper understanding of the life cycles of stars and the elements they release into the cosmos.

For more on this study, see Webb Space Telescope Reveals Mysterious Arcs.

Reference: “JWST observations of the Ring Nebula (NGC 6720): I. Imaging of the rings, globules, and arcs” by R. Wesson, Mikako Matsuura, Albert A. Zijlstra, Kevin Volk, Patrick J. Kavanagh, Guillermo García-Segura, I. McDonald, Raghvendra Sahai, M. J. Barlow, Nick L. J. Cox, Jeronimo Bernard-Salas, Isabel Aleman, Jan Cami, Nicholas Clark, Harriet L. Dinerstein, K. Justtanont, Kyle F. Kaplan, A. Manchado, Els Peeters, Griet C. Van de Steene and Peter A. M. van Hoof, 17 August 2023, Astrophysics > Solar and Stellar Astrophysics.
arXiv:2308.09027

The authors of the paper are part of a scientist’s team named ESSENcE (Evolved StarS and their Nebulae in the JWST Era), is composed experts in planetary nebulae and related objects. Inside this team, Griet Van de Steene and Peter van Hoof study nebulae using imagery and spectroscopy.