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The Daily Wildcat

The Daily Wildcat


Bringing the universe into focus: UA astronomer studies young solar systems

Scattered across the Milky Way, immense clouds of swirling gas and dust are giving birth to stars.

Known as protoplanetary disks, these large gaseous clouds and the stars forming within them have remained a mystery to astronomers.

At least, until now.

A team led by Joshua Eisner, an assistant professor of astronomy at the UA’s Steward Observatory, recently observed the star-forming process within 15 of these protoplanetary disks.

Eisner and his team were able to document the processes giving rise to planets and stars in these nascent solar systems in unprecedented detail.

“”How does a star actually assemble itself is the question we are trying to answer,”” Eisner said. “”No one has been able to probe that problem directly.””

The process starts when a massive cloud of gas molecules and dust particles begins to fold under the influence of its own gravity.

The cloud rotates slowly, becoming denser and more compact as it grows in size. It eventually flattens into a spinning disk of swirling gas and dust that will give rise to a star and possibly planets.

Eisner and his team utilized two powerful telescopes on Mauna Kea, an inactive volcano in Hawaii, along with an instrument named ASTRA (ASTrometric and phase-Referenced Astronomy), to explore the gaseous interactions between a forming star and a protoplanetary disk.

Using the two telescopes and ASTRA, Eisner and his team were able to achieve an angular resolution stronger than that of the Hubble telescope.

The resolution was so strong, in fact, that researchers were able to distinguish for the first time the distributions of gases, mostly hydrogen, thereby resolving the disk’s features.

“”We think we now understand how the gas is going from disk to star … for basically the first time, we can see this happening in young stars,”” Eisner said.

“”It’s kind of a trick,”” he added. “”You synthesize a big aperture instead of building one.””

Eisner said the solar systems his team chose for this study are still young, probably only a few million years old, and are hundreds of light years from our own solar system.

He added that through studying these early-stage protoplanetary disks, scientists will be able to learn more about the formation of our own solar system.

“”We think that our solar system looked like some of these protoplanetary discs millions of years ago. We are observing stars that look a lot like the sun when it was young,”” Eisner said.

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