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Young stars are surrounded by chaos: clouds of gas, dust and ice swirl in the so-called protoplanetary disk. And when gravity pulls this material together, planets are born.
Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, the researchers developed a new technique to measure and date the newborn exoplanets that form in these protoplanetary disks. By studying the “small hurricanes” within the protoplanetary disks that are visible in the ALMA data, astronomers can make educated guesses about the exoplanets that caused these vortices to form.
Under most circumstances, scientists can use powerful telescopes to observe the dimming of stars, which indicates that an exoplanet is transiting or passing between Earth and the star. But this research team is specifically studying young exoplanets that are distant from their stars, and these planets cannot be seen clearly with traditional techniques.
Related: Secrets of the birth of planets revealed in stunning images from the ALMA radio telescope (opens in a new tab)
“It is extremely difficult to study smaller planets that are very far from their star by directly imaging them: it would be like trying to spot a firefly in front of a headlight,” Roman Rafikov, a professor at the University of Cambridge and Institute for Advanced Study, said in a declaration (opens in a new tab). “We need other, different methods to learn about these planets.”
The team’s new technique also uses an indirect form of observation to study exoplanets: Instead of looking for transits, they look for unusual formations, such as arcs or clumps, that form in the protoplanetary disk.
“Something must be causing these structures to form,” Rafikov said. “One of the possible mechanisms for producing these structures, and certainly the most intriguing, is that the dust particles that we see as arcs and clumps are concentrated in the centers of fluid vortices: essentially small hurricanes that can be triggered by a particular instability. at the edges of the holes carved in the protoplanetary disks by the planets”.
By studying the properties of vortices, which require a certain amount of time and mass to form, astronomers can estimate the age and mass of the exoplanet that created them.
“Our limitations can be combined with limits provided by other methods to improve our understanding of planetary characteristics and planet formation pathways in these systems,” Rafikov said. “By studying the formation of planets in other star systems, we can learn more about how our own solar system evolved.”
Two articles on the team’s research have been published in the Monthly Notices of the Royal Astronomical Society: one on the vortices themselves (opens in a new tab) (December 20) and another on using vortices to measure and date exoplanets (opens in a new tab) (January 4).
Originally posted on Space.com.
