'Tiny Speck Of Actual Stardust' Found In Antarctic Meteorite

Scientists have found a grain of stardust that was likely thrown out into space before our own Sun even existed.

The speck of stardust was found inside a chondritic meteorite discovered in Antarctica. While stardust is believed to be the source of many of the raw materials that go into forming suns and planets, it’s very rare to find one intact.

“As actual dust from stars, such presolar grains give us insight into the building blocks from which our solar system formed,” said Pierre Haenecour of the University of Arizona in a statement. “They also provide us with a direct snapshot of the conditions in a star at the time when this grain was formed.”

NASA’s Hubble Space Telescope has revisited the famous Pillars of Creation, revealing a sharper and wider view of the structures in this visible-light image.Astronomers combined several Hubble exposures to assemble the wider view. The towering pillars are about 5 light-years tall. The dark, finger-like feature at bottom right may be a smaller version of the giant pillars. The new image was taken with Hubble’s versatile and sharp-eyed Wide Field Camera 3.The pillars are bathed in the blistering ultraviolet light from a grouping of young, massive stars located off the top of the image. Streamers of gas can be seen bleeding off the pillars as the intense radiation heats and evaporates it into space. Denser regions of the pillars are shadowing material beneath them from the powerful radiation. Stars are being born deep inside the pillars, which are made of cold hydrogen gas laced with dust. The pillars are part of a small region of the Eagle Nebula, a vast star-forming region 6,500 light-years from Earth.The colors in the image highlight emission from several chemical elements. Oxygen emission is blue, sulfur is orange, and hydrogen and nitrogen are green. (Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA))

This particular grain, named LAP-149, can be traced all the way back to a nova explosion that took place billions of years ago. It survived the entire journey through interstellar space and being part of our Solar System for the last 4.5 billion years or more.

It was born in a binary star system in which a white dwarf with a companion star – either a low-mass main sequence star or a red giant – started feasting on its partner. Once the white dwarf chowed down on enough of the companion star, it would have started exploding periodically and spewing out new chemical elements deep into space.

Analysis of this speck proved it was very unusual indeed, challenging some of the current theories of exactly how dying stars seed the Universe with raw materials to make planets, and ultimately, life.

“The carbon isotopic compositions in anything we have ever sampled that came from any planet or body in our Solar System varies typically by a factor on the order of 50,” said Haenecour, who will join the Lunar and Planetary Laboratory as an assistant professor in the fall.

“The ¹³C we found in LAP-149 is enriched more than 50,000-fold. These results provide further laboratory evidence that both carbon- and oxygen-rich grains from novae contributed to the building blocks of our Solar System.”

In addition, the speck is the first known grain consisting of graphite with an oxygen-rich silicate inclusion.

“Our find provides us with a glimpse into a process we could never witness on Earth,” Haenecour added. “It tells us about how dust grains form and move around inside as they are expelled by the nova. We now know that carbonaceous and silicate dust grains can form in the same nova ejecta, and they get transported across chemically distinct clumps of dust within the ejecta, something that was predicted by models of novae but never found in a specimen.”

Unfortunately, the stardust is so tiny, there aren’t enough atoms to date it exactly.

“If we could date these objects someday, we could get a better idea of what our galaxy looked like in our region and what triggered the formation of the solar system,” said Tom Zega, scientific director of the UA’s Kuiper Materials Imaging and Characterization Facility and associate professor in the Lunar and Planetary Laboratory and UA Department of Materials Science and Engineering.

“Perhaps we owe our existence to a nearby supernova explosion, compressing clouds of gas and dust with its shockwave, igniting stars and creating stellar nurseries, similar to what we see in Hubble’s famous ‘Pillars of Creation’ picture.”