Academics and Research / News

DU astronomer earns a view from space

DU astronomer Toshiya Ueta’s proposal earns a $414,000 grant that includes a large block of time to use the Herschel Space Observatory, a European space telescope similar to the United States’ Hubble Space Telescope. Photo: Artist rendering courtesy the European Space Agency/ D. Ducros, 2009

University of Denver Professor Toshiya Ueta deals in the big picture, looking at what’s not visible to human eyes from a platform cloaked in shadow high above the Earth. His quest is to understand the life cycle of stars.

As an astronomer, he studies the very biggest questions of how stars — and their subsequent solar systems — die. How are the next generations of stars born from the ashes of these dead stars? What keeps the cycle continuing?

His work has earned him a coveted block of time as lead investigator to collect data from the Herschel Space Observatory. Like the Hubble Space Telescope, the space-borne platform operated by the European Space Agency in cooperation with NASA has the ability to peer into distant reaches of cold space. Unlike Hubble, Herschel can detect faint heat signals in the far-infrared light generated by remote clouds of “dusty” particles that are believed to be the raw material of stars. The platform allows Ueta to view these clouds through their slight warmth. The Earth’s atmosphere, which is much warmer than cosmic particles, obscures that warmth.

The need to detect even the faintest traces of warmth is why Herschel is stationed permanently behind the Earth’s shadow of the Sun, to keep its ability to investigate the cold universe. When Ueta says “warm,” that term is relative to surrounding space, as in about minus 400 degrees Fahrenheit.

“I’m interested in stars that are like our sun, but older and larger versions of them,” Ueta says. “As they get past ‘middle age,’ stars start losing their surface matter and become a major source of material in space.”

Because he is looking into such distant regions, some 3,000 light years away, everything Ueta sees actually happened at the dawn of the Iron Age, around the time when David was ruler of the ancient Israelites in 1000 B.C.

“When stars get old, they swell up and the gravity gets lower and things start flying off,” Ueta says. “Those will be the building blocks for the next generation of stars. When I talk about this story, I always use the term reincarnation. This is the cosmic reincarnation cycle.”

To make things more complicated, the data Ueta is looking for is heat which isn’t actually visible to the eye. Instead, he will design a series of computer scripts detailing the data he is seeking, which will be collected and translated as numbers. Then, all of that data must be examined and interpreted for him to develop findings. With hundreds of terabytes of data expected, the process will take the volume of funding through NASA and at least three years to complete. It will involve as many as 30 scientists working with Ueta scattered around the globe. Of the project’s $414,000, about $309,000 will be directly under Ueta’s management.

Ueta’s research — dubbed the Herschel Planetary Nebula Survey, or HerPlaNS, for short — uses roughly 3 percent of all the available observation time on the Herschel Space Telescope in 2011, representing what’s believed to be the largest block of time awarded to a researcher from the United States.

To even submit the proposal to access the telescope’s limited time window, Ueta had to learn how the instrument worked and understand how to design computer scripts that will collect the data that will make his work meaningful. Each step of the way has involved intense study. The result, Ueta says, should be scientific evidence that will help us understand the intricate and monumental workings of space, time and matter.

“This is all part of a very long, very complex cycle,” Ueta says. “We are trying to understand the chemical and physical evolution of the universe on a very large scale of space and time.”

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