Nav: Home

Students in right place, right time witness first-ever detected neutron star collision

October 16, 2017

In August, Kaitlin Rasmussen and Devin Whitten, third-year physics graduate students at the University of Notre Dame, were settling into their observation at the Las Campanas Observatory atop a rocky mountain in Las Campanas, Chile, when they saw something unexpected.

Before they arrived, a brief flash of gamma rays was detected 143 million light-years away in a galaxy located in the constellation of Hydra. Accompanying the bright burst were gravitational waves detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO).

All data pointed to a never-before-seen event: the merger of two neutron stars. The light emitted from the collision peaked while Rasmussen and Whitten were on-site.

New research published in Science details perhaps one of the biggest discoveries so far in the field of astrophysics. Rasmussen and Whitten, along with Timothy Beers, chair of astrophysics at Notre Dame, and Vinicius Placco, research assistant professor, contributed to studies published on the collision.

"It's hard to describe the feeling of seeing something with your own eyes that is completely new to science," Rasmussen said. "It's incredible to know that you are one of the few people on the planet, in history, to ever witness a new type of astronomical event. And being included on the paper was a tremendous honor."

Neutron star mergers have proven to be responsible, either in whole or in part, for the formation of nearly half the metals heavier than iron in our solar system including gold, platinum and uranium.

The students had been scouring for a type of star enhanced by a set of reactions called the rapid-neutron capture process, or r-process, on the 2.5-meter Irénée du Pont Telescope owned by the Carnegie Institution for Science.

The concept of the r-process was first suggested in 1957. Astrophysicists theorized that the universe's heaviest elements are formed after a set of reactions, and later suggested this could possibly occur when two neutron stars collide.

Neutron stars -- the densest stars astronomers can visually observe -- result when a supernova collapses and its electrons and protons melt into a neutron core only a few miles wide, yet weighing more than two suns. When two such stars collide, neutron-heavy metals spray outward throughout the universe. The metals become incorporated into the gas clouds of newly minted stars, which is what happened when our sun formed billions of years ago. The same cloud eventually forms planets, like Earth, where the metals are also found.

Light from the collision peaked and then cooled quickly, but continued to radiate for about three weeks. "The best analogy to this collision is fireworks," Beers said. "Initially nothing happens, but then it reaches a critical temperature at which the element that gives off the particular color ignites. So it very rapidly brightens, then falls off."

Placco said that for Whitten and Rasmussen, it was a matter of being in the right place at the right time.

"They're assigned time on the telescope on a semester-by-semester basis, and on a given semester, they could have been there any two nights," he said. "But they were there exactly those two nights."

Now that scientists know neutrons can create the heavy elements through the r-process, they'll redouble efforts to determine whether these neutron star collisions are the only source of those elements, or if another astrophysical event, like a particularly energetic type of supernova explosion, also has a hand in the process, according to Beers.

And there's always that next step in science, when a new discovery unearths even more questions to be explored and answered. Rasmussen and Whitten will move on to answer other astronomical questions and search for even more stars enhanced with r-process elements. But they'll always have the experience of watching a major astronomical event many astrophysicists waited decades to witness.

"Gravitational wave observations represent a new era of astronomy," Whitten said. "We're detecting gravitational events beyond our Milky Way; that's simply amazing. The potential for this new mode of observation to inform us about the galaxy we live in, as well as our local universe, promises much, much more to come."

The research was funded by a grant through the Luksburg Foundation, which encourages Notre Dame partnerships with the Pontifica Universidad Católica de Chile.
-end-


University of Notre Dame

Related Astrophysics Articles:

Astrophysics and AI may offer key to early dementia diagnosis
Crucial early diagnosis of dementia in general practice could improve thanks to a computer model designed in a collaboration between Brighton and Sussex Medical School (BSMS) and astrophysicists at the University of Sussex.
Hubble studies gamma-ray burst with highest energy ever seen
NASA's Hubble Space Telescope has given astronomers a peek at the location of the most energetic outburst ever seen in the universe -- a blast of gamma-rays a trillion times more powerful than visible light.
NASA's TESS presents panorama of southern sky
The glow of the Milky Way -- our galaxy seen edgewise -- arcs across a sea of stars in a new mosaic of the southern sky produced from a year of observations by NASA's Transiting Exoplanet Survey Satellite (TESS).
Giant exoplanet around tiny star challenges understanding of how planets form
An international team of researchers with participation from the University of Göttingen has discovered the first large gas giant orbiting a small star.
'Ringing' black hole validates Einstein's general relativity 10 years ahead of schedule
For the first time, astrophysicists have heard a black hole ringing like a bell.
A family of comets reopens the debate about the origin of Earth's water
Where did the Earth's water come from? Although comets, with their icy nuclei, seem like ideal candidates, analyses have so far shown that their water differs from that in our oceans.
Astronomers discover 2,000-year-old remnant of a nova
For the first time, a European research team involving the University of Göttingen has discovered the remains of a nova in a galactic globular cluster.
Dark matter exists: The observations which question its presence in galaxies disproved
As fascinating as it is mysterious, dark matter is one of the greatest enigmas of astrophysics and cosmology.
Astrophysics: First detailed observations of material orbiting close to a black hole
ESO's GRAVITY instrument confirms black hole status of the Milky Way center.
Time-lapse shows thirty years in the life of supernova 1987A
Yvette Cendes, a graduate student with the University of Toronto and the Leiden Observatory, has created a time-lapse showing the aftermath of Supernova 1987A over a 25-year period, from 1992 to 2017.
More Astrophysics News and Astrophysics 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: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.