IMAGE: Professor Noel Richardson, professor of physics and astronomy at Embry-Riddle, now advised alumna Laura M. Lee, who helped determine the visual orbit and dynamic binary mass of Wolf-Rayet 133. .. view more
Cliu: Embry-Riddle / Jason Kadah
Inside the constellation Cygnus, an old star and his giant companion have one final blow, emitting a mass at an incredible rate before exploding like supernovae and falling into a black hole.
Now, researchers including a recent graduate of Embry-Riddle Aeronautics University, Laura M. Lee, have mapped the orbit of the oldest star around its oversized partner and which is just as old. In scientific first, they have also determined the dynamic magnitude of the two stars that make up a binary system called the Wolf-Rayet 133.
Team Conclusions, published February 9, 2021 by Astrophysical Journal Letters, identified the first ever orbit seen of a rare type of star called the Wolf-Rayet (WN) star filled with nitrogen. That WN star is half the star dance duo in binary WR 133.
The WN star pirouettes around its partner star, a supergiant O9, every 112.8 days – a relatively short orbit, indicating that the two stars are close to each other, researchers said. The WN star is 9.3 times larger than our sun, and the whopping supergiant O9 is 22.6 times larger, the team found.
Thinking of the early world
The exploration opens a new window into the past when stars and planets began to form.
Wolf-Rayet-type stars, so named for the astronauts they discovered in 1867, are big stars near the end of their lives, said Lee’s faculty advisor, Dr. Noel Richardson, a professor of physics and astronomy. experience at Embry-Riddle. They are very hot, a million times brighter than the Sun, and stellar winds have blown away their hydrogen envelopes. That has made it difficult to measure their mass – a crucial step towards shaping the evolution of stars – so far.
Given that the pair of stars in binary WR 133 are closely related, they appear to have exchanged, Richardson noted. “Early in the universe, we think most stars were very large and very likely to explode early,” he said.
“When the types of binary stars are close enough, they can move mass towards each other, possibly kicking up space dust, which is essential for the formation of stars and planets. If they are not close enough to produce mass. still moving a huge wind that burns matter into the cosmos, which can allow stars and planets to form, which is why we want to find out more about the universe. This is a rare type of star. “
Lee was still an undergraduate at Embry-Riddle when Richardson invited her to help solve an interesting astronomy puzzle, as part of her masterpiece project. Richardson had been analyzing data from the CHARA Array, a collection of six telescopes located throughout Mount Wilson in California. The field, which is run by the University of High Angular Resolution Astronomy Center, could draw square-to-square-foot details in New York City from the telescopes near Los Angeles, California.
Lee’s special job was to make sense of about 100 spectra – barcode-like graphs that show how much light is emitted. To better understand the WR 133 spectra, provided by Grant M. Hill of the Keck Observatory in Hawaii, Lee used computer code that allowed the team to measure how the two stars were moving. “These measurements are a necessary step because they tell us how the stars move back and forth from us, while the CARA measurements tell us how they move across the sky,” Richardson explained. “The combination gives us the ability to see a three – dimensional orbit, which then tells us the masses. “
At the time, Lee was focusing with a laser on earning her Embry-Riddle degree. “I didn’t really realize how much of an impact we were making in this area,” said Lee, a member of the Sigma Pi Sigma physics honors association who now holds a minor in Astronomy. Mathematical. “It was really exciting to be part of the project, especially as an undergraduate student.”
‘Blue marble in space’
At the Armagh Observatory & Planetarium in Northern Ireland, one of the many centers involved in the project, Andreas AC Sander, said the team ‘s findings were somewhat surprising and will lead researchers to rethink key assumptions. “The results are very interesting because they produce a lower-than-expected mass for a star like that,” Sander noted.
“While this may sound like a detail, it will change our view of the Black Holes that come from falling Wolf – Rayet stars, which is very important in the celestial context of gravitational wave events. “
Gail Schaefer of CHARA Array noted that Richardson’s ideas using Georgia State University (GSU) telescopes on Mount Wilson – made possible through an open access program at the facility – “will help advance our understanding on how binary interactions affect the evolution of these. big stars. “
Embryo-Riddle astronomer Jason Aufdenberg, who has also used the CHARA Array, said that “the kind of work Noel does, establishing orbits, is very important because they can get these things how many there were and their lights as part of understanding what happened in our universe after the Big Bang. “
Now at the beginning of her career, Lee said she hopes to keep learning and surprise us with our universe. “We’re on blue marble floating in space,” she said. “It’s important to learn more about the complexity of the universe around us. People are born to learn. Any knowledge we can have is a gift.”
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The research project involved colleagues from many parts of the world and several institutions. In addition to Embry-Riddle, Chara Array at GSU, Armagh Observatory and Keck Observatory, the work involved Michigan State University, University of Arizona, University of Denver, University of Exeter in the United Kingdom, Belgian Institute of Astronomy and Institute of Planetology and Astrophysics in France.
The Astrophysical Journal Letters the paper is titled “The First Dynamical Mass Determination of a Visual and Spectroscopic Wolf-Rayet Orbit Full of Nitrogen.” Journalists, request the full paper if you cannot access it:
https: /
(DOI: 10.3847 / 2041-8213 / abd722.)
An introductory version of the paper is available online here: https: /
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