The growth process of a planetary system is actually quite painful. They continue to experience collisions and slowly merge from a small asteroid into a larger celestial body, such as the earth and the moon. Although we cannot witness the past of the solar system, we can glimpse this collision from other systems. Recently, astronomers have discovered signs of planetary collisions around the young star HD 172555. The impact was so intense that the planetary atmosphere was stripped.
A large number of studies have shown that there were many large-scale impact events in the early solar system. The earth and the moon were all products of continuous impact and fusion from the protoplanetary disk. However, scientists still rarely observe similar large-scale impacts in other systems. .
At 95 light-years from the Earth, there is a young star named HD 172555, which is only 23 million years old. Scientists used to have an unusual mineral composition and particles that are much finer than expected typical stellar dust disks. It is suspected that there may have been a collision in its dust ring not long ago.
A team led by the Massachusetts Institute of Technology recently used the Atacama Large Millimeter/Submillimeter Array (ALMA) to observe around stars and determined that an Earth-sized terrestrial planet collided with another smaller celestial body 200,000 years ago , The collision speed is 10 kilometers per second.
Spectral characteristics indicate that a large amount of carbon monoxide orbits the star at an unusually close distance. At this distance, the gas should have been completely decomposed by the stellar radiation, unless an earth-sized rocky planet was hit by an object not long ago, from the planet’s atmosphere. The blown-off carbon monoxide has not had time to decompose before it can interpret this data.
The research team pointed out that if we find a large amount of carbon monoxide around other stars in the future, it is likely to be a sign of chaotic variables in the formation of the planetary system, which can help us count the number of large-scale impact events. The new paper was published in the journal Nature.
(Source of the first image: Massachusetts Institute of Technology)
