New, stunningly detailed images captured by the James Webb Space Telescope have provided the scientific community and the public with an unprecedented view into the very heart of one of the most beautiful and complex objects in the night sky – the Butterfly Nebula, also known by its catalog designation NGC 6302. These infrared eyes in space have pierced through the dense veils of gas and dust to reveal the dynamic processes taking place around a dying star, offering a breathtaking portrait of cosmic transformation. From the dense, dusty torus-shaped structure surrounding the central, hidden star, to the jets of material erupting from its poles, Webb's observations paint a completely new, vivid picture of this fascinating planetary nebula.

Unveiling the cosmic butterfly

Located at a distance of approximately 3,400 light-years in the constellation Scorpius, the Butterfly Nebula has been an object of admiration and study for decades. Its delicate, symmetrical structure, reminiscent of a butterfly's outstretched wings, has made it one of the most photogenic objects in deep space, and it has been previously imaged on multiple occasions by the legendary Hubble Space Telescope. However, Webb, with its ability to observe in the infrared spectrum, opens a completely new chapter in understanding this celestial jewel.

Planetary nebulae, despite their name, have nothing to do with planets. The name is a historical misconception that arose several centuries ago when astronomers, using the telescopes of the time, noticed that these objects had a round, disk-like appearance similar to planets. Although the name has remained, today we know that planetary nebulae are actually the final, magnificent stage in the life of stars similar to our Sun. When stars with masses between 0.8 and 8 times that of the Sun exhaust their nuclear fuel, they cast off their outer layers of gas into space. These ejected layers, illuminated and energized by the ultraviolet radiation from the hot core of the remaining star, begin to glow, creating the spectacular shapes and colors we see. This phase of stellar evolution, known as a planetary nebula, is a cosmic blink of an eye, lasting only about twenty thousand years.

The Butterfly Nebula is an excellent example of a bipolar nebula, meaning it has two clearly defined lobes or "wings" that expand in opposite directions from the center. The dark band of gas and dust that bisects the center of the nebula and forms the "body" of the butterfly is actually a dense, ring-shaped torus that we are viewing from the side. It is this torus that plays a key role in shaping the nebula, acting as a barrier that prevents gas from flowing out uniformly in all directions and channels it towards the poles, creating the characteristic bipolar structure.

Heart of darkness: The search for the hidden star

One of the greatest achievements of the new Webb observations is the precise location of the central star of the Butterfly Nebula. This star, the ancient and incredibly hot core of a former Sun-like star, has so far been elusive to observations in the optical part of the spectrum. The reason for its invisibility lies precisely in the dense dusty torus that surrounds it, which effectively blocks all visible light. Previous searches for the star lacked the combination of infrared sensitivity and spatial resolution needed to penetrate this dusty curtain.

Using its Mid-Infrared Instrument (MIRI), Webb was able to detect the thermal glow of the dust cloud located immediately around the star, which was heated by the star itself. This allowed scientists to determine its location with high precision. The temperature of this central star is estimated to reach an incredible 220,000 Kelvin (about 220,000 °C), making it one of the hottest known stars in our galaxy. It is this blazing stellar engine that powers the entire nebula with its energy and makes it visible, and its power, it seems, is channeled precisely through the dense dusty belt that surrounds it.

Anatomy of the dusty ring

The new Webb image, obtained through a combination of the MIRI instrument's camera and spectrograph, provides an unprecedented insight into the complex structure of the central torus. Data analysis has revealed that this ring is composed of a mixture of crystalline silicates, such as quartz, as well as irregular, amorphous dust grains. The size of these dust grains is on the order of a millionth of a meter, which is considered quite large on a cosmic scale. Such a size suggests that the grains have had enough time to grow and agglomerate, indicating a long and stable formation process within this dense environment. The composition and structure of this torus are key to understanding not only the shape of the Butterfly Nebula but also the chemical processes that occur in the final stages of stellar evolution.

Chemical fingerprints in the nebula's wings

Thanks to its spectrographic capabilities, analysis of Webb's data has allowed scientists to identify nearly 200 spectral lines. Each of these lines represents a unique "fingerprint" of a specific atom or molecule, revealing detailed information about the chemical composition, temperature, and density of the gas in different parts of the nebula. This data reveals a complex, nested, and interconnected structure traced by different chemical species.

A clear layered structure has been observed. Ions that require the most energy to form, such as those of highly ionized elements, are concentrated closest to the hot central star. On the other hand, those that require less energy are found at greater distances. Elements like iron and nickel have proven particularly interesting, as they trace the path of two powerful jets erupting from the star in opposite directions, breaking through the surrounding gas.

Unexpected discovery: Molecular building blocks

Perhaps the most intriguing discovery to come from these observations is the detection of light emitted by complex carbon-based molecules known as polycyclic aromatic hydrocarbons (PAHs). These molecules have flat, ring-like structures, similar to a honeycomb. On Earth, PAH molecules are often found in campfire smoke, car exhaust, or on burnt toast. Their presence in space is of great interest because they are considered one of the potential building blocks for more complex organic molecules.

What makes this discovery special is the location where the PAH molecules were found. The research team suspects that these molecules were formed when a "bubble" of stellar wind, originating from the central star, broke through the surrounding denser gas. This could be the first direct evidence of PAH molecule formation in an oxygen-rich planetary nebula, providing a crucial insight into the details of the chemical pathways by which these important molecules are formed. This discovery raises new questions about carbon chemistry in space and the conditions under which the precursors of life can form.

Synergy of telescopes: Webb, Hubble, and ALMA

This study, the results of which were published in the prestigious journal Monthly Notices of the Royal Astronomical Society, is a perfect example of how modern astronomy advances through the synergy of different observatories. Although Webb provides revolutionary data, it is complemented by archival data from the Hubble telescope, as well as data obtained from the Atacama Large Millimeter/submillimeter Array (ALMA), a powerful network of radio antennas in Chile. While Hubble provides a sharp view in the visible and near-ultraviolet spectrum, and ALMA maps cooler gas and dust via radio waves, Webb's ability to peer into the infrared heart of the nebula completes the picture, allowing for the most comprehensive understanding of the Butterfly Nebula to date. Webb, as an international partnership of NASA, ESA, and CSA, continues to fulfill its promise as the most powerful space telescope ever launched, opening new windows into the universe and uncovering the secrets of the cosmos hidden from our eyes.