a primitive family asteroids It provides a window into the past for astronomers trying to unravel the history of these small space rocks that are believed to have once existed. brought water with Soil.
Life solar system can be dangerous as many effects have occurred throughout history; for example, giant impact we created moon or many impacts resulting in a cratered surface Mercury. Sometimes large asteroids in the main region asteroid beltlocated between Anthem and Jupiter was also struck. When this happened, these asteroids would break up into smaller pieces. Events like this can generate several dozen smaller events space rocks; Naturally, many bits from the same original object have some things in common, such as moving in similar orbits. Astronomers call groups of such asteroids “families.”
More than 120 such families are known to exist in the asteroid belt. Some, like the Vesta family, named after the second largest object in the belt 4 Vestashows evidence of chemical change. Being this massive, Vesta went through a process known as differentiation, as well as heating, before it was struck by another asteroid and partially disintegrated; In this process, heavier elements collapsed into its core and formed various layers.
Relating to: No need for asteroid impact: Newborn Earth produced its own water, according to research
But eight of the asteroid families retain their primitive chemistry. Astronomers are very interested in these pristine samples because their primitive compositions can provide insight into the conditions of our solar system when the pioneer asteroids of these families formed. In other words, they can help us discover the secrets of the universe. antique Solar system. That’s why University of Central Florida planetary scientist Noemí Pinilla-Alonso is co-leading a project called the Primitive Asteroid Spectroscopic Survey (PRIMASS) to chronicle the chemical composition of these asteroid families.
Finally, this work was completed thanks to Pinilla-Alonso’s Ph.D. student Brittany Harvison, who took on the task of examining infrared observations of the Erigone family of primitive asteroids, the last family to be examined for the PRIMASS project. The Erigone family is a relatively young family from a cosmic perspective, as the collision that created it is estimated to have occurred only 130 million years ago.
“There are theories that Earth may have gotten some of its water from primitive asteroids in the early solar system,” Harvison said. expression. “A big part of these theories is understanding how these primitive asteroids were transported into Earth’s path. So discovering primitive asteroids in the solar system today could help paint a picture of what was going on many years ago.”
Using near-infrared observations taken by NASAHarvison analyzed the composition of 25 members of the Erigone family with the 3.2-meter Infrared Telescope Facility in Hawaii and the 3.58-meter Telescopio Nazionale Galileo in Spain’s Canary Islands. The group takes its name from its largest member, the 72-kilometer (44.7-mile) asteroid 163 Erigone.
Harvison found that 43% of the Erigone family, including 163 Erigone, are C-type carbonaceous asteroids, meaning they are rich in carbon. It is not surprising that many members of the Erigone family are type C, as this is the most common type of asteroid overall and often contains evidence of hydrated or water-bearing minerals. Therefore, C-type asteroids are indeed leading candidates for bringing water to Earth.
As for the rest of the Erigone family, 28% consists of type X asteroids, which are likely of different types and have similar spectra to the rest of their clan. B-types, a type of carbonaceous asteroids, make up 11% of the Erigone family, while unknown T-types make up 7%. There are also the stony L and S types, which appear to be non-primitive interlopers rather than true members of the family.
But Harvison’s real discovery is that all Erigone family members share a similar basic composition that is not repeated by any other primitive asteroid family. In fact, all families are unique with their own different levels of hydration. Being able to match which asteroid families have the highest water content will help point astronomers in the right direction as they search for the culprits that brought water to Earth.
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Because the Erigone family consumes so much liquid, they have now become an important target for astronomers. This being the case, NASA’s Lucy upcoming space mission JupiterTrojan asteroids will first visit asteroid 52246 Donaldjohanson. Named after an American paleoanthropologist, this C-type asteroid is a member of the Erigone family, so scientists will be able to get a close look when Lucy flies past on April 20, 2025.
PRIMASS team also won successfully time on James Webb Space Telescope Observing the Erigone family (and other primitive asteroids) starting this summer. Findings from JWST and Lucy will further reveal the history of these ancient objects and begin to fill gaps in our knowledge of the solar system and Earth’s past.
Harvison’s research was published in the April 2024 issue. Icarus.