Now, astronomers have discovered 30 exocomets, or comets, located outside our solar system, orbiting the Sun-like Beta Pictoris star, which makes it even more interesting.
The Beta Pictoris star was discovered about 40 years ago. It is surrounded by a disk of debris made of gas and dust, which has already given birth to two young planets orbiting the star. This gives researchers a rare opportunity to see the planetary system that is in the process of being formed. While our solar system is 4.5 billion years old, Beta Pictoris is only 20 million years old – which is astronomically young.
Scientists were able to detect a few comets orbiting the star in early 1987, making them the first comets to observe a star other than our Sun.
An international research team observed the Beta Pictoris system for 156 days using NASA’s Transiting Exoplanet Survey Satellite, or TESS, mission.
In addition to discovering 30 exocomets, researchers were able to determine the size of the comet’s center – the icy “dirty snowballs” that make up the comet’s heart. When comets pass close to a star, the star’s heat causes their ice to rise, creating long, long tails that can spread behind the comet.
The center of exocomets is between 1.8 and 8.7 miles (3 and 14 kilometers) in diameter, similar to comets in our own solar system. This is the first time that astronomers have measured the size distribution of comets in other planetary systems.
In Beta Pictoris, comets “steal stars almost every day,” said Alain Lacavlier des Itangs, a CNRS researcher at the Institute de Astro Physics de Paris.
Just as comet astronomers study in our solar system, the shape of exocomets is formed by collisions with other objects.
Lecavelier des Etangs said that “this shows the importance of communication, collision, material exchange in the early stages of life of planets and small bodies such as asteroids or comets.”
Some of the water on Earth may have been created by comets and their ice content, so scientists are curious to know what effect comets have on exoplanets.
“We cannot be sure that the observed comets have the potential to deliver water-like material to the planets orbiting Beta Pectoris, but our observations show that collisions are very common and therefore suggest Mild planets can be enriched by material trapped in frozen ice captured by comets. (Comets) are very far from the stars and later collide with the planets, “he said.
Lecavelier des Etangs said that although there are many similarities between the exocomets of Beta Pictoris and the comets of our solar system, the exact similarities and differences are still to be determined.
Exocomets can generally help shed light on the origin and evolution of comets, and future observations of planetary systems using the Hubble and James Webb Space Telescope can reveal more details about them.
“The question of the structure of these comets remains open,” he said.
Researchers want to determine which substance converts from solid to gas, as the Exocomets Beta Pictoris approaches the star. It could be water ice, carbon monoxide or something else.
The system has a unique combination of three factors that keep astronomers coming back to: it is young, close and telescopes have the best view of it from Earth.
“Nature gave us such an amazing goal,” said Lecavelier des Etangs. “Lots of questions open up. I’m sure Beta Pictoris will keep us busy for decades to come!”