Categories: world

Here are 20 protoplanetary dishes, with newly formed planets that cut away gaps in gas and dust

Hunting on other planets in our galaxy has been heated in recent decades, with 3869 planets being detected in 2,886 systems and another 2,898 candidates waiting for confirmation. Although the discovery of these planets has taught scientists a lot about the kind of planets found in our galaxy, there is still a lot we do not know about the process of planetary formation. To answer these questions, an international team recently used the Atacama Large Millimeter / Submillimeter Array (ALMA) to conduct the first large-scale, high-resolution survey of protoplanetary disks around nearby stars. Known as a disk base at the High Angular Resolution Project (DSHARP), this program provided high resolution images of 20 adjacent systems where dust and gas were about to form new planets. Their results were divided into a series of ten papers that will be displayed in a special issue of The Astrophysical Journal Letters . The responsible group comprised members of the Harvard Smithsonian Center for Astrophysics (CfA), Joint ALMA Observatory, and several observers, research institutes and universities. This artist's view shows a newly formed star surrounded by a swirling protoplanetic disk of dust and gas. Credit: Copenhagen University / Lars Buchhave At any rate, DSHARP researchers noted the presence of slots in the disc that were far from the central star and seemed to delimit the inner and outer parts of the disc. The resulting rings were also tightly packed or formed thinner bands, depending on their distance from the star. These patterns, which they…

Hunting on other planets in our galaxy has been heated in recent decades, with 3869 planets being detected in 2,886 systems and another 2,898 candidates waiting for confirmation. Although the discovery of these planets has taught scientists a lot about the kind of planets found in our galaxy, there is still a lot we do not know about the process of planetary formation.

To answer these questions, an international team recently used the Atacama Large Millimeter / Submillimeter Array (ALMA) to conduct the first large-scale, high-resolution survey of protoplanetary disks around nearby stars. Known as a disk base at the High Angular Resolution Project (DSHARP), this program provided high resolution images of 20 adjacent systems where dust and gas were about to form new planets.

Their results were divided into a series of ten papers that will be displayed in a special issue of The Astrophysical Journal Letters . The responsible group comprised members of the Harvard Smithsonian Center for Astrophysics (CfA), Joint ALMA Observatory, and several observers, research institutes and universities.

This artist’s view shows a newly formed star surrounded by a swirling protoplanetic disk of dust and gas. Credit: Copenhagen University / Lars Buchhave

At any rate, DSHARP researchers noted the presence of slots in the disc that were far from the central star and seemed to delimit the inner and outer parts of the disc. The resulting rings were also tightly packed or formed thinner bands, depending on their distance from the star. These patterns, which they suggest, may be the result of an invisible planet that interferes with the disk.

Another possibility is that the disc structures are subject to a global instability similar to those seen in spiral galaxies (like Winter Street). According to the researchers, the most convincing explanation is that large planets (eg gas giants) formed the bulk of the outer surface of the disc, which would indicate that planetary formation occurs much faster than current theories of planning the planet.

This possible explanation could also help explain how ground planets (ie rocky and similar in size to earth) approaching their stars can survive the early stages of their formation. Sean Andrews, an astronomer at the Harvard-Smithsonian Center for Astrophysics (CfA) and one of the leaders * in the ALMA Observation Campaign, explained the importance of these findings in a NRAO press release:

“The goal of this month-long observation campaign was to ALMA’s remarkably sharp vision has revealed previously invisible structures and unexpectedly complex patterns. We see clear details about a wide range of young stars of different masses. The most convincing interpretation of these very varied small-scale features is that there are invisible planets that interact with the disc material. “

Branded version of four of the twenty discs that include ALMA’s highest resolution of nearby protoplanetary discs. Credit: ALMA (ESO / NAOJ / NRAO) S. Andrews et al.; NRAO / AUI / NSF, S. Dagnello

According to the leading models of planetary formation, planets are born of gradual collection of dust and gas inside a protoplanetic disk. This begins with a vacuum cleaner to form larger and larger stones until asteroids, planes and planets appear. This process is assumed to take millions of years, which means that protoplanetary discs in older systems would be more visibility influenced by it.

Early observations of ALMA, however, indicated that many young protoplanetary discs had well-defined structures like rings and gaps. These features are usually associated with the presence of the planets and were even found in a few systems that were only one million years old. As Jane Huang, a PhD student at CfA and a member of the research group, explained:

“It was surprising to see possible signatures of planetary formation in the very first high resolution images on young discs. It was important to find out if these were deviations or if these signatures were common in discs. “

As the early test set was so small, the DSHARP campaign was mounted to observe other protoplanetic discs for comparison. Because dust particles are known to glow in the millimeter wavelength, the campaign team could use the ALMA matrix to accurately map the density of dustbars around young star systems and (depending on the star’s distance) to mapping functions as small as some astronomical devices.

Image of HL Tau-planetary disc taken with Atacama Large Millimeter Array. Credit: ALMA (ESO / NAOJ / NRAO)

At the end, the research team found that many of the substructures (ie concentric slots and narrow rings) were common to almost all discs, while large-scale spiral patterns and arc-like functions were more rare. They also found that the slices and slots were present at a wide range of distances from their host stars – from a few AU to more than one hundred.

As noted, these observations can help solve a lasting mystery when it comes to theories of planetary formation. Specifically, astronomers have wondered how planets could be formed when the dynamics of a smooth protoplanetary disc would lead to a body that is more than one centimeter in diameter falling into its host star. Under these circumstances, stony objects larger than an asteroid should not exist.

In essence, they would seal the rings of dust. The observed team created disturbances in the disc, which could create zones where the planetesimals would be safe and have the time they needed to grow into planets. As Laura Perez, a researcher at Chile University and a member of the research group, stated:

“When ALMA really revealed its ability with its iconic image of HL Tau, we must wonder if it was an outlier since the counter was relatively massive and young . These latest observations show that HL Tau, although striking, is far from unusual and can actually represent the normal development of planets around young stars. “

This research shows the power of recent instruments and scientific Collaboration has today. Thanks to the ability to see more and look further, researchers can test astronomical theories like never before. And in the process, our most basic concept of how the universe came to be confirmed and challenged.

Be sure to enjoy this animation of what a protoplanetic disc looks like, with the permission of the NRAO Outreach Program:

* The other leaders of the ALMA Observation Campaign are Andrea Isella of Rice University, Laura Pérez from Chile University and Cornelis Dullemond at Heidelberg University.

Further reading: NRAO [19659026] How to:

Like Loading …

Share
Published by
Faela