In Search of Ancient Planets, Scientists Unveil Unexpected Events


Graphic design of a protoplanetary disk with small planets forming around a star.

Using ALMA (Atacama Large Millimeter / submillimeter Array), astronomers have for the first time recorded the disk of a nearby star HD 53143 at a distance of millimeter wavelengths, and it does not look as expected.

Based on previous experience, scientists expect ALMA to confirm the disposal disk as a front, drop and dust ring.

Instead, the mirrors changed dramatically, revealing a trash disc. complex and eccentric he saw. The statement was made at a press conference at the 240th session of the American Astronomical Society in Pasadena, California. It will be published in the next issue Letters from the Astrophysical Journal.

Price 53143 – nearly a billion-year-old Sun-shaped star, located 59.8 years from Earth in the constellation Carina – was first seen in 2006 by the ACS Telescope (Advanced Camera for Surveys). Hubble Space.

Around it there is also a waste disk – a belt of star-shaped comets constantly colliding and “grinding” into fine dust and debris – which scientists initially thought was a ring similar to the garbage disk that orbits the Earth. known as the Kuiper Belt.

ALMA’s new concept of HD 53143, using its Band 6 receptors, has shown that the star’s waste disk is eccentric. In the ring-shaped disks, the star is usually located in the middle of the disk or near.

But in eccentric, elliptical disks, the star is located on the edge of the ellipse, far away from the center of the disk. This is the case with HD 53143, which has not been seen in previous coronagraph studies, because the coronagraph blocks the brightness of the starlight to see closer objects. The star system can also have a second disk and one planet.

“Until now, scientists I have never seen a garbage disk with such a complex shape. In addition to being a star-shaped ellipse, it also has a second internal disk that is distorted or tilted from the outer disk, “said Meredith MacGregor, assistant professor at CASA (Center for Astrophysics and Space Astronomy) and the Department of Astrophysics and Planetary. Sciences at the University of Colorado, Boulder, senior author of the study.

“In order to make this system, there must be a planet or planets in a system that interferes with the contents of the disk.”

This level of eccentricity, MacGregor said, makes HD 53143 the largest discarded disk to date, twice as large as the Fomalhaut disk, which MacGregor recorded entirely in millimeter waves using ALMA in 2017.

“So far, we haven’t found many good disks. In most cases, we do not expect the disks to be hidden unless something, like a planet, sculpts them and forces them to rotate. Without that power, circular paths tend to be round, as we see in our Sun. .

MacGregor points out that waste disks do not just collect dust and stones in the atmosphere. It is a history of planetary design and the evolution of planets. And He gives you your future.

“We cannot directly study the design of the Earth and the Sun, but we can learn about other systems that are similar to ours. It’s like looking back. ”he said.

“Waste disks are a history of planetary production and the new result is to ensure that there is more to learn and the process is such that knowledge can give us an idea of ​​the intricacies of a solar system similar to our solar system. ”

Doctor. Joe Pesce, NSMA program manager at NSF, adds: “We find planets everywhere we look and these positive results from ALMA show us how they are made – both close to other stars and individually. This study shows how astronomical science it works and how it progresses, not just in what we know about the work, but also in ourselves. ”

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