UT undergrad discovers elusive companion star to Beta Canis Minoris

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STAR SEARCHER: Nick Dulaney, a junior majoring in physics, helped discover the star Beta Canis Minoris is actually a binary star, or a double star.

Nick Dulaney was determined to solve a galactic mystery. Why is there an unexpected, wavy edge on a disk around a bright, rapidly rotating star located 162 light years away from Earth?

The junior studying physics at the University of Toledo spent last summer analyzing 15 years of spectroscopic archive data collected at the Ritter Observatory on campus and discovered that Beta Canis Minoris, which is three and a half times larger than the sun and easily visible to the naked eye, is not alone.

With the help of UT post-doctoral research associate Dr. Noel Richardson and Dr. Jon Bjorkman, professor of physics and astronomy, Dulaney found that the highly-studied star featuring a disk around its equator is actually a binary star, or a double star.

“A low-mass secondary star orbits around Beta Canis Minoris,” Dulaney said. “While it’s circling the bright star, the smaller star stops the disk on the bigger star from getting too big by creating a wave in the disk.”

Beta Canis Minoris is what is known as a Be star, a hot star that rotates so fast that the material on its equator is ejected into a large gaseous disk surrounding the star.

“Nick discovered that the star was moving back and forth every 170 days,” Richardson said. “This motion is caused by the pull of the companion star and is very difficult to measure.”

Dulaney also found that the companion star tugs extra material from the disk towards it. This causes the observations to change repeatedly every time the star orbits. The student’s findings are leading new efforts by Bjorkman’s international modeling team to determine how the stars interact.

Dulaney is the lead author on the research paper recently published in the Astrophysical Journal. He worked on the project while participating in UT’s Research Experience for Undergraduates program sponsored by the National Science Foundation.

“This is a big milestone for me and shows that I am progressing towards building a career,” Dulaney said. “Doing this research has given me valuable experience, and I am very grateful to the NSF and The University of Toledo for the opportunity.”

“Many students don’t have similar publications until halfway through their graduate programs,” Richardson said. “As an undergraduate, Nick has shown that he is capable of collecting and analyzing data, and then communicating the results with scientists. These skills will serve him well in his future and shows the strengths of our undergraduate program at the University of Toledo.”

Dulaney started using the Ritter Observatory as a freshman and is one of nearly two dozen undergraduates making up a team who use the observatory every clear night. The students help graduate students in making the measurements and operating the telescope.

“This student observing team is a gem for the University,” said Dr. Karen Bjorkman, dean of the UT College of Natural Sciences and Mathematics, Distinguished University Professor of Astronomy and Helen Luedtke Brooks Endowed Professor of Astronomy. “Nick’s project highlights how our one-meter telescope on campus is used for both educational and scientific missions.”

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