With the help of the NASA / ESA / CSA James Webb space telescope, astronomers have gone a big leap in understanding how the raw material of the rocky planets gathers. This cosmic material – crystalline silicate dust and polycyclic aromatic hydrocarbons have been studied at the heart of a spectacular bipolar planetary nebula called nebula of butterflies.
Hubble and webb / alma images of the butterfly nebula. Image credit: NASA / ESA / CSA / Webb / Hubble / Alma / Matsuura and al., DOI: 10.1093 / minras / Staf1194.
The butterfly nebula, otherwise known as NGC 6302, is among the best studied planetary nebulae.
This nebula is located at around 2,417 light years of the earth in the Constellation of Scorpius.
Its butterfly shape stretches for more than two light years, about half of the distance from the sun near the Centauri.
The object shows a bipolar morphology, extreme complex, the presence of very high excitation gas, high molecular mass and crystalline silicate dust.
“The planetary nebulae is among the most beautiful and elusive creatures of the cosmic zoo,” said the astronomer of the University of Cardiff, Mikako Matsuura and his colleagues.
“These nebulae are formed when stars with masses between about 0.8 and 8 times the mass of the sun have lost most of their mass at the end of their lives.”
“The planetary nebula phase is ephemeral, only lasts 20,000 years.”
“Unlike the name, the planetary nebulae has nothing to do with the planets: the confusion of name began several hundred years ago, when astronomers reported that these nebulae appeared, as planets.”
“The name has remained, even if many planetary nebulae are not at all round – and the butterfly nebula is an excellent example of the fantastic forms that these nebulae can take.”
“The butterfly nebula is a bipolar nebula, which means that he has two lobes that spread in opposite directions, forming the” wings “of the butterfly”, they added.
“A dark dusty gas band pretends to be for the” body “of the butterfly. This group is actually a torus in the shape of a section that we see aside, hiding the central star of the nebula – the old nucleus of a star similar to a sun which energizes the nebula and makes it shine.”
“The dusty donut can be responsible for the insectoid shape of the nebula by preventing gas from flowing from the outside of the star also in all directions.”
The new image of the median webb infrared instrument zoards on the center of the butterfly nebula and its dusty torus, offering an unprecedented view of its complex structure.
Astronomers have identified nearly 200 spectral lines, each containing information on atoms and molecules in the nebula.
These lines reveal nested and interconnected structures drawn by different chemical species.
The researchers also identified the location of the central star of the butterfly nebula, which heats up a cloud of dust previously not detected around it, which makes the latter shine with medium infrared wavelengths to which Miri is sensitive.
With a temperature of 220,000 Kelvin, it is one of the hottest central stars known in a planetary nebula of our galaxy.
This image takes the spectator in deep diving into the heart of the butterfly nebula, as webb shows. Image credit: NASA / ESA / CSA / Webb / M. Matsuura / ALMA / ESO / NAOJ / NRAO / N. HIRANO / M. ZAMANI.
“This flamboyant stellar engine is responsible for the magnificent gleam of the nebula, but its full power can be channeled by the dense gaz of dusty gas around it: the torus,” said the authors.
“The new webb data show that the torus is made up of crystalline silicates such as quartz as well as dust grains of irregular shape.”
“Dust grains have sizes on the order of a millionth of meters – largely, with regard to cosmic dust – indicating that they have been developing for a long time.”
“Apart from the torus, the issue of different atoms and molecules takes on a multilayer structure.”
“The ions that require the greatest amount of energy to form are concentrated near the center, while those which require less energy are found further from the central star.”
“Iron and nickel are particularly interesting, drawing a pair of jets that explode outwards the star in opposite directions.”
Curiously, the team also spotted the light emitted by carbon molecules called polycyclic aromatic hydrocarbons (HAP).
“They form flat and annular structures, just like the honeycomb forms found in the hives,” said astronomers.
“On Earth, we often find HAP smoked in camp fires, car exhaust or burnt toast.”
“Given the location of the HAP, we suspect that these molecules are formed when a” bubble “of the central star bursts in the gas around it.”
“It can be the very first proof that the HAPs are formed in a planetary nebula rich in oxygen, offering an important overview of the details of the way in which these molecules form.”
The results were published this week in the Monthly opinion from the Royal Astronomical Society.
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Mikako Matsuura and al. 2025. The JWST / MIRI view of the planetary nebula NGC 6302 – I. A TORE irradiated by UV and a training of inhabitants triggering a hot bubble. Mnra 542 (2): 1287-1307; DOI: 10.1093 / minras / Staf1194
