Researchers Discover A Planet Losing Its Atmosphere After A Massive Impact

Astronomers have detected something for the first time that is believed to the common in young developing solar systems. A team led by researchers at MIT has discovered evidence of a massive planetary impact in a nearby star system known as HD 17255. In that star system, researchers believe a planet similar in size to the Earth and a smaller impactor body likely collided within the last 200,000 years.

Resulting from the massive collision, some of the planet's atmosphere has been stripped away. While this type of collision is known to happen and believed to be common in developing solar systems, it has never been directly observed. In our solar system, collisions of this sort are known to have occurred, and the moon is believed to have been created during an impact between Earth and another body early in its formation.

HD 17255 is close to our solar system on a cosmic scale at only 95 light-years away. The star in its center is called HD 172555, and it's about 23 million years old. Researchers believe the star's dust has traces of this collision. Astronomers observed additional evidence of a massive impact around the star, determining that the collision likely occurred between an approximately Earth-sized terrestrial planet and a smaller impactor at least 200,000 years ago. The impact is believed to have occurred at a speed of more than 22,000 miles per hour.

One of the most crucial discoveries in the research is gas that indicates the high-speed impact blew away part of the larger planet's atmosphere. That event would explain the observed gas and dust orbiting the star. Study lead author Tajana Schneiderman says this is the first time scientists have detected the phenomenon of a stripped protoplanetary atmosphere resulting from an impact.