WASHINGTON (Reuters) – The Ring Nebula, a stunning celestial structure located in our neighborhood of the Milky Way, was discovered by French astronomer Charles Messier in 1779 and has been studied extensively ever since. But that doesn’t mean we’ve got it all figured out.
Researchers observed a large cloud of iron atoms in the form of a ribbon extending about 3.7 trillion miles (6 trillion kilometers) across the face of the nebula, which is a glowing shell of gas and dust expelled by a dying star, and were searching for an explanation.
They said it is possible that the iron atoms, which collectively are comparable to the mass of Earth’s molten iron core, are the remains of a rocky planet that evaporated when the star shed its outer layers, though they cautioned that such an explanation is just speculation at the moment. The rocky inner planets of our solar system, and perhaps even Earth, could face the same fate when the Sun undergoes the same death throes billions of years from now.
The researchers made the observation using a new instrument called WEAVE, short for WHT Enhanced Area Velocity Explorer, on the William Herschel Telescope, located on the Atlantic island of La Palma in Spain’s Canary Islands.
“It is exciting to see that even a very familiar object – one that has been studied extensively over many decades – can elicit a new surprise when observed in a new way,” said astronomer Roger Wesson of Cardiff University in Wales and University College London, lead author of the research published in the Monthly Notices of the Royal Astronomical Society.
“It’s a classic object that professional and amateur astronomers alike can observe,” Wesson said. “Although it is too faint to be seen with the naked eye, it is very easy to see with binoculars. In a small telescope, you can see the ring-like appearance.”
The ring nebula, also called Messier 57, is located about 2,600 light-years from Earth in the constellation Lyra. A light year is the distance light travels in a year, which is 5.9 trillion miles (9.5 trillion km). It is believed to have formed approximately 4,000 years ago, which is very recent in cosmic time.
It is familiar even to novice astronomy students.
“You’ll find it in many astronomy textbooks,” said Janet Drew, an astronomer at University College London and co-author of the study.
This is why the iron rod is so interesting.
“No other chemical element we have discovered appears to be in this same strand. This is frankly strange. Its importance lies in the simple fact that we have no ready explanation for it yet,” Drew said. “The origin of the iron could be from the evaporation of a planet. But there could be another way to create the feature that doesn’t involve a planet.”
“A planet like Earth has enough iron to form a penis, but how it would end up as a penis is not a good explanation,” Wesson said.
The nebula formed when a star roughly twice the mass of the Sun ran out of nuclear fuel, inflated into a so-called red giant and shed its outer layers before becoming a compact stellar remnant known as a white dwarf, roughly the size of our planet.
“From Earth’s perspective, it looks like a ring, although it is thought that it actually resembles a cylinder of material that we see from its end,” Wesson said. “It is composed mostly of hydrogen and helium, with small amounts of heavier elements.”
About 3,000 of these nebulae are known in our galaxy. Studying it allows astronomers to examine the life stage of stars when chemical elements formed by nuclear processes within them are released into interstellar space to be recycled and contribute to the next generation of stars and planets.
“We are looking forward to obtaining more data to follow up on this discovery, to try to uncover this new problem and determine the source of the iron rod,” Wesson said.
(Reporting by Will Dunham, Editing by Daniel Wallis)