MU professor will look 12 million years into the past on Webb telescope

Professor Aigen Li will use the telescope to study star formation history by looking at the contents of the M82 galaxy.

The flight mirrors for the James Webb Space Telescope undergo cryogenic testing at NASA Marshall in 2011. Credit: Ball Aerospace

Some of the biggest news of MU physics professor Aigen Li’s year arrived with a small ding on his phone. Sitting at his desk from home, Li saw an email from NASA saying his proposal to use the James Webb Space Telescope was accepted.

“You can imagine that observation time is very precious,” Li said, speaking of the powerful telescope that recently reached its orbit nearly 1 million miles from Earth.

By this summer, the telescope could begin sending back never-before-seen images of the universe.

“If you simply get one hour of observation time, in this industry it’s lucky,” Li said. “So we’re really looking forward to it.”

Li and his collaborator, postdoctoral student Jianwei Lyu from the University of Arizona, won $150,000 and 10.2 hours with the James Webb Space Telescope, which reached its final orbit around Earth on Monday.

Li said his former post-doctorate scholar Xuejuan Yang, also contributed to the proposal.

Li, who is the principal investigator for the project, plans to study the M82 galaxy.

“We’re very proud of Aigen and all of our astronomers in our department,” said Paul Miceli, University of Missouri physics and astronomy department chair. “His observation time from NASA with this new telescope will be a great benefit to Mizzou and to our students.”

Students won’t be able to use a joystick to play with the telescope. All that is controlled by NASA.

But students will have a chance to work with Li on this project and gain technical knowledge that will help them build their careers after they graduate.

This diagram shows Webb's trajectory from Earth into its orbit around the Second Langrange point. Graphic credit: NASA/Steve Sabia

The telescope allows researchers to look back in time. For instance, the M82 galaxy is 12 million light-years away. But it takes 12 million years for light from the M82 galaxy to reach us.

“What we see right now actually happened 12 million years ago,” Li said. “This is amazing, isn’t it? If you had a friend on a planet in M82, and you want to call him, you would need to wait millions of years to hear back from him.”

The telescope also works in infrared light, which is low-energy, has a long wavelength and is outside the visible range of light.

“Events that happen very early in the formation of the universe will be visible only in the infrared,” Miceli said. “So, it extends the time period that astronomers can look back into.”

This infrared capability is key to Li’s research.

Within the M82 galaxy are special molecules called polycyclic aromatic hydrocarbon, or PAH. These molecules are composed of benzene rings and emit infrared radiation. So, the telescope can easily detect these molecules.

The M82 galaxy is very active in forming stars. It creates approximately 100 stars per year, while the Milky Way only creates about three stars per year. Li wants to know how these molecules survive such a violent starburst environment.

“There must be a reason, so we want to find out the physics behind it,” Li said.

Based on the emission of these molecules, Li can potentially determine how these molecules are processed in M82 and how their infrared emission accurately measures the number of stars made per year. This, in turn, can give a clue into the star formation history of this universe.

“(The PAH molecules) are an important part of the materials that build up the galaxy,” Lyu said. “It’s not wildly abundant compared with stars and dust, but it’s still an important component to regulate the evolution of the galaxy. Lots of people are interested to know how this molecule evolves for different environments.”

Li and Lyu won’t receive any photos until late October after the telescope has cooled down and stabilized its orbit. In the meantime, the two researchers are planning for the second round of proposals. Next time, they hope to study a nearby comet with the telescope.

Several other University of Missouri researchers also are co-investigators on different James Webb Space Telescope projects, including Hoajing Yan, Daniel McIntosh, Kameswara Mantha and Benjamin Floyd.

Originally published by the Columbia Missourian.