(ORDO NEWS) — Astronomers, using a complex of the world’s leading telescopes on earth and in space, have received images of the decay of a periodic rocky comet near the Sun.
This is the first time such a comet has been captured in the process of disintegration, and it may help explain the rarity of such periodic comets near the Sun.
The solar system is a dangerous place. In textbooks, we see the figures of celestial bodies revolving around the Sun in ordered orbits. But that’s because if an object’s orbit doesn’t follow this pattern, gravitational effects from other objects will destabilize the orbit.
One common fate for such ejected bodies is to become comets in solar orbits, where they eventually crash into the Sun. Because these comets pass so close to the Sun, they are difficult to detect and study.
Most of them were discovered by accident during observations with solar telescopes. But even with these difficulties, there are far fewer comets near the Sun than expected, indicating that something is destroying them before they have a chance to make their fateful final plunge into the Sun.
To better understand these comets, a team of astronomers from Macau, USA, Germany, Taiwan and Canada observed an elusive comet near the Sun called 323P/SOHO using several telescopes, including the Subaru Telescope, the Canada-France-Hawaii Telescope (CFHT), the Gemini North Telescope, the Lowell Discovery Telescope and the Hubble Space Telescope. 323P/SOHO’s orbit was poorly constrained, so the team didn’t know where to look, but Subaru’s wide field of view allowed them to cast a wide net and find the comet as it approached the Sun.
This was the first time that 323P/SOHO had been imaged with a ground-based telescope. With this data, the researchers were able to better determine the orbit, they knew where to point other telescopes, and they waited for 323P/SOHO to start moving away from the Sun again.
To their surprise, the researchers found that 323P/SOHO changed dramatically during its close pass of the Sun. In the Subaru telescope data, 323P/SOHO was just a dot, but in later data it had a long cometary tail of ejected dust.
The researchers believe that the Sun’s intense radiation caused parts of the comet to break off in a thermal breakdown similar to how ice cubes crack when a hot drink is poured over them. This mass loss mechanism could help explain what happens to comets near the Sun and why there are so few of them left.
However, the results of the team’s work raised more questions than they answered. They found that 323P/SOHO spins very fast, just over half an hour per revolution, and that its color is unlike anything else in the solar system. It is necessary to make observations of other comets near the Sun to find out if they have the same features.
“We would not have been able to make this discovery without the Maunakea telescope observations made possible by the University of Hawaii,” says Man-To Hui, who was a University of Hawaii research fellow at the time of the observations and is now an assistant professor at the Macau University of Science and Technology.
Observations from the Subaru Telescope led the way, reducing the uncertainty of the orbit and enabling follow-up observations. CFHT provided the data with the best coverage and Gemini provided the densest data points.”
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