Nav: Home

Seeing the light: MSU research finds new way novae light up the sky

April 13, 2020

EAST LANSING, Mich. - A nova, or stella nova, the Latin word for "new star," is an explosion on the surface of a star that can produce enough energy to increase the star's brightness by millions of times. Sometimes a nova, which occur in stars called white dwarfs, is so bright it appears as a new star to the naked eye.

The explosion occurs when a white dwarf star strips material from its companion star that piles up on the dwarf's surface, eventually triggering a thermonuclear explosion. While for many years astronomers have thought that nuclear burning of material on the surface of the white dwarf directly powered all the light from the explosion, more recently astronomers started debating that "shocks" from the explosion might power most of the brightness.

Now, an international team of astronomers from 40 institutes across 17 countries led by Michigan State University's Elias Aydi, has found that it is indeed shocks that cause most of the nova's brightness.

The research is detailed in a paper published in the journal Nature Astronomy titled, "Direct evidence for shock-powered optical emission in a nova."

"This is a new way of understanding the origin of the brightness of novae and other stellar explosions," said Aydi, a research associate in MSU's Department of Physics and Astronomy. "Our findings present the first direct observational evidence, from unprecedented space observations, that shocks play a major role in powering these events."

So, what are shocks and how do they form? Picture a supersonic jet airplane. When the jet exceeds the speed of sound, it produces a shock which leads to a loud sonic boom. In a nova explosion, the shocks produce light rather than sound.

When material blasts out from the white dwarf, said Aydi, it is ejected in multiple phases and at different speeds. These ejections collide with one another and create shocks, which heat the ejected material producing much of the light.

Another side effect of astronomical shocks are gamma-rays, the highest-energy kind of electromagnetic radiation. The astronomers detected bright gamma-rays from the star, known as nova V906 Carinae, whose explosion in the constellation Carina was first detected in March 2018.

Using NASA's Fermi Gamma-ray Space Telescope, they showed that V906 Car had the brightest gamma-rays ever observed for a nova, proving that it hosts energetic shocks.

But the real surprise came because an optical satellite - one of the six nanosatellites that make up a collection of satellites operated by an international consortium called the BRight Target Explorer Constellation of cube-sats - just happened to be looking at the part of the sky where the nova occurred. Comparing the gamma-ray and optical data, the astronomers noted that every time there was a fluctuation in gamma-rays, the light from the nova fluctuated as well.

"We observed simultaneous fluctuations in both the visual and gamma-ray brightness, meaning that both emissions are originating from shocks," said Kirill Sokolovsky, a research associate at MSU and a co-author on the paper. "This led us to the conclusion that shocks are indeed responsible for most of the brightness of the event."

"We were lucky that members of our team were observing that part of the sky with these special satellites and were able to collect this unprecedented set of data," Aydi said.

The team estimates that V906 Car is about 13,000 light years from Earth. This means that when the nova was first detected in 2018, it had actually happened 13,000 years ago.

This new information may also help explain how large amounts of light are generated in other stellar events, including supernovae and stellar mergers, in when two stars collide with one another. Other MSU researchers involved in the project are Laura Chomiuk, Jay Strader and Adam Kawash, all of the Department of Physics and Astronomy.
-end-
(Note for media: Please include a link to the original paper in online coverage: https://www.nature.com/articles/s41550-020-1070-y)

Michigan State University has been working to advance the common good in uncommon ways for 160 years. One of the top research universities in the world, MSU focuses its vast resources on creating solutions to some of the world's most pressing challenges, while providing life-changing opportunities to a diverse and inclusive academic community through more than 200 programs of study in 17 degree-granting colleges.

For MSU news on the Web, go to MSUToday. Follow MSU News on Twitter at twitter.com/MSUnews.

Michigan State University

Related Science Articles:

75 science societies urge the education department to base Title IX sexual harassment regulations on evidence and science
The American Educational Research Association (AERA) and the American Association for the Advancement of Science (AAAS) today led 75 scientific societies in submitting comments on the US Department of Education's proposed changes to Title IX regulations.
Science/Science Careers' survey ranks top biotech, biopharma, and pharma employers
The Science and Science Careers' 2018 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.
Science in the palm of your hand: How citizen science transforms passive learners
Citizen science projects can engage even children who previously were not interested in science.
Applied science may yield more translational research publications than basic science
While translational research can happen at any stage of the research process, a recent investigation of behavioral and social science research awards granted by the NIH between 2008 and 2014 revealed that applied science yielded a higher volume of translational research publications than basic science, according to a study published May 9, 2018 in the open-access journal PLOS ONE by Xueying Han from the Science and Technology Policy Institute, USA, and colleagues.
Prominent academics, including Salk's Thomas Albright, call for more science in forensic science
Six scientists who recently served on the National Commission on Forensic Science are calling on the scientific community at large to advocate for increased research and financial support of forensic science as well as the introduction of empirical testing requirements to ensure the validity of outcomes.
World Science Forum 2017 Jordan issues Science for Peace Declaration
On behalf of the coordinating organizations responsible for delivering the World Science Forum Jordan, the concluding Science for Peace Declaration issued at the Dead Sea represents a global call for action to science and society to build a future that promises greater equality, security and opportunity for all, and in which science plays an increasingly prominent role as an enabler of fair and sustainable development.
PETA science group promotes animal-free science at society of toxicology conference
The PETA International Science Consortium Ltd. is presenting two posters on animal-free methods for testing inhalation toxicity at the 56th annual Society of Toxicology (SOT) meeting March 12 to 16, 2017, in Baltimore, Maryland.
Citizen Science in the Digital Age: Rhetoric, Science and Public Engagement
James Wynn's timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ.
Science/Science Careers' survey ranks top biotech, pharma, and biopharma employers
The Science and Science Careers' 2016 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.
Three natural science professors win TJ Park Science Fellowship
Professor Jung-Min Kee (Department of Chemistry, UNIST), Professor Kyudong Choi (Department of Mathematical Sciences, UNIST), and Professor Kwanpyo Kim (Department of Physics, UNIST) are the recipients of the Cheong-Am (TJ Park) Science Fellowship of the year 2016.
More Science News and Science Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Biology Of Sex
Original broadcast date: May 8, 2020. Many of us were taught biological sex is a question of female or male, XX or XY ... but it's far more complicated. This hour, TED speakers explore what determines our sex. Guests on the show include artist Emily Quinn, journalist Molly Webster, neuroscientist Lisa Mosconi, and structural biologist Karissa Sanbonmatsu.
Now Playing: Science for the People

#569 Facing Fear
What do you fear? I mean really fear? Well, ok, maybe right now that's tough. We're living in a new age and definition of fear. But what do we do about it? Eva Holland has faced her fears, including trauma and phobia. She lived to tell the tale and write a book: "Nerve: Adventures in the Science of Fear".
Now Playing: Radiolab

The Wubi Effect
When we think of China today, we think of a technological superpower. From Huweai and 5G to TikTok and viral social media, China is stride for stride with the United States in the world of computing. However, China's technological renaissance almost didn't happen. And for one very basic reason: The Chinese language, with its 70,000 plus characters, couldn't fit on a keyboard.  Today, we tell the story of Professor Wang Yongmin, a hard headed computer programmer who solved this puzzle and laid the foundation for the China we know today. This episode was reported and produced by Simon Adler with reporting assistance from Yang Yang. Special thanks to Martin Howard. You can view his renowned collection of typewriters at: antiquetypewriters.com Support Radiolab today at Radiolab.org/donate.