Huge collision cost the planet its atmosphere
Such violent encounters are likely to be common in young solar systems – our group included. But this is the first time researchers have found evidence of this.
The formation of a planetary system is often somewhat chaotic. For example, it is not uncommon for objects to collide. When this happens, celestial bodies can fuse to form larger planets. The Earth and Moon in our solar system are also thought to be the product of such gigantic collisions. So astronomers suspect that such violent encounters are common in young solar systems. But do you really prove it? This is another story.
However, surprisingly, researchers have now succeeded in doing so. in a New study Watch Hot White Star HD 172555; A young star about 23 million years old and about 95 light years from Earth. This star has long attracted the attention of scientists. This is because the composition of the dust swirling around it is somewhat unusual. For example, the dust contains large amounts of unusual minerals, confined to much finer grains than astronomers expect. “Given these two factors, HD 172555 is thought to be an exotic system,” said study leader Tajana Schneiderman.
The researchers wondered what this dust might reveal about the history of the system. Using the Chilean Millimeter Large Atacama Array (ALMA), the team scanned for signs of carbon monoxide. “When studying the gas in debris disks, carbon monoxide is usually the brightest and therefore easiest to find,” Schneiderman explains. So the researchers set out to find it.
And successfully. Because after careful analysis, the researchers were able to detect carbon monoxide around the star. They find that there is a great deal of carbon monoxide orbiting the star, at an unusually close distance of just 10 AU (astronomical units; 1AU is the distance from Earth to the Sun). The researchers looked at several scenarios to explain this remarkable abundance of carbon monoxide so close to the star. In the end, there was only one possibility: the gas is the remnant of a massive collision. “Out of all the scenarios, this is the only one that can explain all the features,” Schneiderman said.
According to the researchers, the gas was released during a massive collision between a rocky planet – roughly the size of Earth – and a smaller impactor. It is assumed that the Earth-like planet collided with this smaller body at a speed of up to 10 kilometers per second. This encounter occurred about 200,000 years ago, so the star did not have time to clean up the gas. Given the amount of carbon monoxide the researchers detected, they suspected it was a massive hit. It’s so dangerous, in fact, that one of the planets has – at least partially – been ripped apart from its atmosphere, which researchers have now observed as gas.
This means that researchers have now discovered, for the first time, evidence of violent clashes in young planetary systems. “This is the first time that we have detected a bare plantar atmosphere caused by a massive impact,” Schneiderman concluded. Many people are interested in studying such collisions because we expect them to happen frequently. However, we have not found any evidence of this yet. But now, thanks to the study, we are gaining more insight into the dynamics.”
In this regard, this research is an important starting point for other scientists. Because detecting carbon monoxide in other systems may also provide more insight into their violent past. “We propose a new way to search for giant collisions,” Schneiderman said. “In addition, we are also now gaining a better understanding of how debris behaves in its wake.”
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