UT astronomer joined NASA team in identifying star system

Dr. Noel Richardson, a Ritter Postdoctoral Research Associate in the University of Toledo Department of Physics and Astronomy, is pictured Friday, July 6, 2018, at the Brooks Observatory at the University of Toledo.

The Blade/Katie Rausch
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When most people glance up at the night sky, they see stars shining light years away. For Noel Richardson, postdoctoral research associate in the University of Toledo Department of Physics and Astronomy, the experience is much different.

Being a part of the international team in 2016 that discovered a massive star system 7,500 light years away, Mr. Richardson helped analyze data about Eta Carinae, the first star system to be observed by NASA’s NuSTAR space telescope.

Dr. Noel Richardson, a Ritter Postdoctoral Research Associate in the University of Toledo Department of Physics and Astronomy, is pictured Friday, July 6, 2018, at the Brooks Observatory at the University of Toledo.

“What was really interesting with this recent discovery was that we found shocks [cosmic rays] between two very massive stars that can actually accelerate particles up to near the speed of light,” Mr. Richardson said. “[The rays] can get deflected in different ways every time they come near a star, planet or anything in space.”

Since most stars don’t produce enough energy to be observed with the X-ray telescope, the telescope is typically used for viewing black holes and other galaxies. However, Eta Carinae emitted high energy X-rays, making the NuSTAR telescope an integral part of this discovery.

Eta Carinae is a binary system in which two stars go around each other in an elliptical orbit. While the two stars spend most of their time apart for their five and a half year period, in the course of a couple of months, the stars get very close and go around in an inner circle.

Mr. Richardson’s fascination with astronomy developed during his undergraduate years while using telescopes. After finishing his master’s degree in physics at UT, the astronomy fanatic received his doctorate at Georgia State University.

He soon began his astronomy career at the University of Montreal, continuing to work with telescopes and developing an interest in massive stars.

“They are actually double, triple stars in the way they are formed,” he said of the cosmic giants. “So, this recent discovery we announced was doing things with very high energy X-rays.”

Unlike his usual projects that involve optical light (what the human eye registers), this discovery marked the first time Mr. Richardson had worked with X-rays.

“The X-rays tell us something more about how the winds of different stars hit each other, how they produce shocks and what these shocks are doing in order to create the light that we see,” Mr. Richardson said.

Ken Sembach, left, speaks with Noel Richardson as they look over the University of Toledo's telescope at Ritter Planetarium.

He added that high-energy radiation — also known as cosmic rays — constantly bombards the atmosphere. While the atmosphere protects us from these rays, some invariably penetrate the atmospheric protection.

“We don’t know where they come from, but now we do know that at least this type of star system can produce [cosmic rays] and you don’t need exploding stars [to generate them] which is what we thought before,” Mr. Richardson said in explaining the new discovery.

Eta Carinae, first came to scientific attention in the 19th Century after astronomer John Herschel observed it in South Africa, said Rudi Linder, professor emeritus of history and astronomy at the University of Michigan. “So any research on that object is going to attract some attention,” she said.

This discovery of cosmic radiation from Eta Carinae resulted from the efforts of 12 astronomers from Japan, United Kingdom, United States, and Canada. Knowing that the twin stars in the system grow even closer for several months for the 5½-year period, they prepared several telescope proposals hoping to discover something new the next time the phenomenon took place.

It took a full day of observation for the telescope to gather enough light to discern what the star was doing.

“What we found was that it changed in similar ways as other X-ray light curves we had seen in the past, and NuSTAR was able to pinpoint where the X-rays were coming from,” Mr. Richardson said.

After confirming the high energy photons were arising from Eta Carinae, the team realized the star system was a source of cosmic rays. While they had suspected this before, no one had ever verified this claim, making the discovery all the more exciting, Mr. Richardson said.

Kenji Hamaguchi, astrophysicists at NASA’s Goddard Space Flight Center in Maryland and lead author for this study, said astronomers will continue to use the NuStar Space telescope to observe the star system.

“We know the components, we know how the star shoots the high-energy particles, but we don’t know how the activity changes with the orbit,” he said. “We know some of it, but we don’t know everything yet.”

Sanjay Khare, chair of the UT department of physics and astronomy, said an important aspect of this discovery is that it used several telescopes to collect data to form a complete picture of the constellation.

Professor Khare called the Eta Carinae discovery a pioneering study that will lead the way for astronomers to look at other binaries or bright sources of cosmic rays. They should now be better able to pinpoint where a flux of cosmic rays is coming from within a particular system .

“It’s going to open a new area,” the department chair said. “At this point it’s just a prediction so we don’t know how many objects will be found, but it opens up a whole new area.”

For Noel Richardson, the most exciting part about this discovery was getting a paper published in Nature Astronomy, a scientific journal that reports groundbreaking discoveries. This is the first time a UT astronomer has published an article in the prestigious journal.

His search for new discoveries continues.

“I want to go to the next step with several of the stars I’ve worked with for several years, which will require a lot of telescope time and resources,” he said with a smile.

Contact Areeba Shah at ashah@theblade.com, 419-724-6066, or on Twitter @areebashah_.