In a new study by Chinese, German, and American astronomers, they have revealed how the most distant celestial body “visited” by human probes, Arokos, has changed from “round” to “flat” and “slim”. This research may help humans uncover more mysteries of the formation and evolution of celestial bodies in the early solar system.
Arokos is a primitive celestial body in the Kuiper Belt at the edge of the solar system. It is also the most distant and oldest celestial body ever observed by humans at close range. From the initial photos, Arokos looks like a “snowman” in the border of the solar system. This small celestial body with a total length of about 36 kilometers is composed of two spheres connected by a relatively small “neck” in the middle. However, as the later observational data continued to be enriched, it was discovered that Arokos was not as “round and round” as previously thought. Viewed from the side, the “Snowman”‘s belly has become shriveled and his head has become a bumpy flat ball. The two “spheres” that make up it are actually more similar to two flat discs. Such a shape is quite different from the generally considered spherical or ellipsoidal primitive planets.
In this research, astronomers solved the mystery of the shape of Arokos through simulation. Zhao Yuhui, an associate researcher of the Purple Mountain Observatory who led this research, said that the reason why the “snowman” became “flat” was related to the special rotation mode.
Studies have shown that Arokos is an icy celestial body with extremely low surface temperature, almost “lying” on its orbital surface to rotate, which makes different areas of Arokos receive different intensities of solar radiation.
”The’Snowman’ may be really’round’ at first, but the solar radiation received by the poles of Arokos is much larger than the equator, which makes the’Snowman’ lose more volatile matter on the front and back sides, and appear flatter than the side. Calculations show, Ah Rokos’s “slimming” process occurred within 1 million to 100 million years after its formation. This is almost the starting point for the development of the solar system, and many ancient icy celestial bodies may have similar evolutionary history.” Zhao Yuhui said.
Related research results have been published in the academic journal “Nature·Astronomy” recently.
Demystifying how the “farthest celestial body” “slims down”
