Searching for planet-forming fossils, scientists reveal unexpected quirks

Searching for planet-forming fossils, scientists reveal unexpected quirks


Artist’s rendering of a protoplanetary disk, in which young planets form around stars.

Using ALMA (Atacama Large Millimeter/Submillimeter Array), astronomers imaged the debris disk of neighboring star HD 53143 at millimeter wavelengths for the first time, and it looked nothing like they expected.

Based on earlier coronal data, scientists expect ALMA to identify the debris disk as a frontal ring filled with clumps of dust.

Instead, the observations took a surprising turn, revealing a disk of debris. more complex and quirky Observed. The remarks were made during a press conference at the 240th meeting of the American Astronomical Society in Pasadena, California.will be featured in an upcoming magazine astrophysical journal letters.

HD 53143 – An approximately 1 billion-year-old Sun-like star at the base of Carina, 59.8 light-years from Earth – first observed in Hubble in 2006 using the telescope’s ACS (Advanced Camera for Surveys) instrument.

Surrounding it is also a debris disk — a belt of comets orbiting the star, constantly colliding and “grinding” into smaller dust and debris — a frontal ring that scientists previously thought was similar to the debris disk orbiting Earth. Our Sun, more commonly known as the Kuiper Belt.

ALMA’s new observations of HD 53143, using its highly sensitive band 6 receptor, reveal that the star system’s debris disk is highly eccentric.In the annular debris disk, the star is Usually at or near the center of the disk.

But in an eccentric elliptical disk, the star is located at one of the foci of the ellipse, away from the center of the disk. This is the case with HD 53143, which has not been observed in previous coronagraph studies because coronagraphs deliberately block light from the star in order to see nearby objects more clearly. The star system may also contain a second disk and at least one planet.

“Until now, scientists Never seen a fragmented disk with such a complex structure. In addition to being an ellipse with a star at its focus, it may also have a second inner disk that is misaligned or tilted with the outer disk,” said Meredith McGregor, assistant professor at CASA (Center for Astrophysics and Space Astronomy) in Colorado. PhD in astrophysics and planetary sciences from the University of Boulder and lead author of the study.

“To produce this structure, there must be one or more planets in the system gravitationally perturbing the material in the disk.”

This level of eccentricity makes HD 53143 the most eccentric debris disk ever observed, with twice the eccentricity of the Fomalhaut disk, MacGregor said, which MacGregor photographed entirely at millimeter wavelengths using ALMA in 2017. disk.

“So far, we haven’t found many disks with significant eccentricity. In general, we don’t expect disks to be very eccentric, unless something, like a planet, is sculpting them and forcing them to be eccentric. Without this force, the orbits It tends to be circular, as we see in our solar system.”

McGregor pointed out that the debris disk is not just a collection of dust and rocks in space. They are historical records of how planets formed and how planetary systems evolved. They can see into your future.

“We cannot study the formation of the Earth and the solar system directly, but we can study other systems similar to ours. It’s kind of like going back in time. “Say.

“The debris disk is the fossil record of planet formation, and this new result is Confirm that there is still a lot to learn With these systems, this knowledge can give us a glimpse into the complex dynamics of young star systems similar to our solar system. “

doctor. Joe Pesce, ALMA program officer at NSF, added: “We look for planets everywhere we look, and these amazing results from ALMA show us how they form — including around other stars and in our own solar system. This research shows how astronomy works and how progress can be made to understand not only the field but ourselves.”

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