A team of astronomers has identified a planet similar to Earth that may have lost some of its atmosphere two hundred thousand years ago due to a collision. 

Only 95 light-years away from Earth, MIT, National University of Ireland Galway, and Cambridge University astronomers discovered evidence of the huge collision in a nearby star system. The HD 172555 star is around 23 million years old, and astronomers believe its dust indicates a recent collision.

Mᴀssive impacts, according to a research published in the journal Nature, are responsible for planets like the early Earth reaching their final mᴀss and achieving long-term stable orbital arrangements. 

An important prediction is that debris will be generated by these hits. The researchers discovered a carbon monoxide gas ring co-orbiting with dusty debris around HD172555 between six and nine astronomical units — a zone akin to the outer terrestrial planet area of our Solar System.

Astronomers are attracted by the star HD 172555 due to the odd composition of its dust, which apparently contains a considerable amount of exotic materials in grains much smaller than astronomers would expect. 

Tajana Schneiderman, a doctoral student in the Department of Earth, Atmospheric, and Planetary Sciences at MIT, searched through data from Chile’s Atacama Large Millimeter Array (ALMA) in search of carbon monoxide traces encircling close stars.

The ALMA observatory is a network of 66 radio telescopes whose distance apart may be altered to increase or decrease image resolution.

“When attempting to examine gas in debris discs, carbon monoxide is often the brightest and hence the simplest to locate. Therefore, we reexamined the carbon monoxide data for HD 172555 since it was an intriguing system,” stated Schneiderman. The researchers identified carbon monoxide, which accounted for 20% of the carbon monoxide measured in Venus’ atmosphere, after a thorough analysis of the data.

Surprisingly close to the star, at around 10 astronomical units, or 10 times the distance between Earth and the sun, mᴀssive volumes of gas were swirling. The presence of such a vast amount of gas encircling the star necessitated an explanation, and scientists considered several possibilities.

Astronomers investigated theories in which the gas was formed by the debris of a newly born star and by a nearby belt of ice asteroids, but rejected both. The most plausible hypothesis explored by the scientists is that the gas was a byproduct of a major collision.

It is the only scenario that can explain all the characteristics of the data. In systems of this age, we anticipate gigantic repercussions, and we anticipate that these impacts will be relatively common. The timelines, age, and morphological and compositional limitations are all consistent. In this system, the only probable process that may create carbon monoxide is a mᴀssive impact, Schneiderman said in a statement.

The team hypothesizes that the gas was discharged by a catastrophic collision at least 200,000 years ago, which is recent enough for the star not to have completely destroyed the gas. According to the amount of gas, the impact was likely mᴀssive, involving two protoplanets around the size of Earth.

According to astronomers, the impact was so violent that a piece of one planet’s atmosphere was blown away, resulting in the gas observed today.