Doe Science news source
The DOE Science News Source is a Newswise initiative to promote research news from the Office of Science of the DOE to the public and news media.
  • 2017-08-02 12:05:31
  • Article ID: 678938

New Simulations Could Help in Hunt for Massive Mergers of Neutron Stars, Black Holes

Berkeley Lab scientists develop detailed models that provide new views of cataclysmic events in space

  • Credit: Classical and Quantum Gravity

    This image, from a computerized simulation, shows the formation of an inner disk of matter and a wide, hot disk of matter 5.5 milliseconds after the merger of a neutron star and a black hole.

  • Credit: Classical and Quantum Gravity

    Early “snapshots” from a simulation of a neutron star-black hole merger. This entire animated sequence occurs within 43 milliseconds (43 thousandths of a second).

Now that scientists can detect the wiggly distortions in space-time created by the merger of massive black holes, they are setting their sights on the dynamics and aftermath of other cosmic duos that unify in catastrophic collisions. 

Working with an international team, scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have developed new computer models to explore what happens when a black hole joins with a neutron star – the superdense remnant of an exploded star.

Using supercomputers to rip open neutron stars 

The simulations, carried out in part at Berkeley Lab’s National Energy Research Scientific Computing Center (NERSC), are intended to help detectors home in on the gravitational-wave signals. Telescopes, too, can search for the brilliant bursts of gamma-rays and the glow of the radioactive matter that these exotic events can spew into surrounding space.

In separate papers published in a special edition of the scientific journal Classical and Quantum Gravity, Berkeley Lab and other researchers present the results of detailed simulations.

One of the studies models the first milliseconds (thousandths of a second) in the merger of a black hole and neutron star, and the other details separate simulations that model the formation of a disk of material formed within seconds of the merger, and of the evolution of matter that is ejected in the merger. 

That ejected matter likely includes gold and platinum and a range of radioactive elements that are heavier than iron.

Any new information scientists can gather about how neutron stars rip apart in these mergers can help to unlock their secrets, as their inner structure and their likely role in seeding the universe with heavy elements are still shrouded in mystery.

“We are steadily adding more realistic physics to the simulations,” said Francois Foucart, who served as a lead author for one of the studies as a postdoctoral researcher in Berkeley Lab’s Nuclear Science Division. 

“But we still don’t know what’s happening inside neutron stars. The complicated physics that we need to model make the simulations very computationally intensive.” 

Finding signs of a black hole–neutron star merger 

Foucart, who will soon be an assistant professor at the University of New Hampshire, added, “We are trying to move more toward actually making models of the gravitational-wave signals produced by these mergers,” which create a rippling in space-time that researchers hope can be detected with improvements in the sensitivity of experiments including Advanced LIGO, the Laser Interferometer Gravitational-Wave Observatory.

In February 2016, LIGO scientists confirmed the first detection of a gravitational wave, believed to be generated by the merger of two black holes, each with masses about 30 times larger than the sun.

The signals of a neutron star merging with black holes or another neutron star are expected to generate gravitational waves that are slightly weaker but similar to those of black hole–black hole mergers, Foucart said. 

Radioactive ‘waste’ in space

Daniel Kasen, a scientist in the Nuclear Science Division at Berkeley Lab and associate professor of physics and astronomy at UC Berkeley who participated in the research, said that inside neutron stars “there may be exotic states of matter unlike anything realized anywhere else in the universe.”

In some computer simulations the neutron stars were swallowed whole by the black hole, while in others there was a fraction of matter coughed up into space. This ejected matter is estimated to range up to about one-tenth of the mass of the sun.

While much of the matter gets sucked into the larger black hole that forms from the merger, “the material that gets flung out eventually turns into a kind of radioactive ‘waste,’” he said. “You can see the radioactive glow of that material for a period of days or weeks, from more than a hundred million light years away.” Scientists refer to this observable radioactive glow as a “kilonova.”

The simulations use different sets of calculations to help scientists visualize how matter escapes from these mergers. By modeling the speed, trajectory, amount and type of matter, and even the color of the light it gives off, astrophysicists can learn how to track down actual events. 

The weird world of neutron stars

The size range of neutron stars is set by the ultimate limit on how densely matter can be compacted, and neutron stars are among the most superdense objects we know about in the universe.

Neutron stars have been observed to have masses up to at least two times that of our sun but measure only about 12 miles in diameter, on average, while our own sun has a diameter of about 865,000 miles. At large enough masses, perhaps about three times the mass of the sun, scientists expect that neutron stars must collapse to form black holes.

A cubic inch of matter from a neutron star is estimated to weigh up to 10 billion tons. As their name suggests, neutron stars are thought to be composed largely of the neutrally charged subatomic particles called neutrons, and some models expect them to contain long strands of matter – known as “nuclear pasta” – formed by atomic nuclei that bind together.

Neutron stars are also expected to be almost perfectly spherical, with a rigid and incredibly smooth crust and an ultrapowerful magnetic field. They can spin at a rate of about 43,000 revolutions per minute (RPMs), or about five times faster than a NASCAR race car engine’s RPMs.

The aftermath of neutron star mergers

The researchers’ simulations showed that the radioactive matter that first escapes the black hole mergers may be traveling at speeds of about 20,000 to 60,000 miles per second, or up to about one-third the speed of light, as it is swung away in a long “tidal tail.”

“This would be strange material that is loaded with neutrons,” Kasen said. “As that expanding material cools and decompresses, the particles may be able to combine to build up into the heaviest elements.” This latest research shows how scientists might find these bright bundles of heavy elements.

“If we can follow up LIGO detections with telescopes and catch a radioactive glow, we may finally witness the birthplace of the heaviest elements in the universe,” he said. “That would answer one of the longest-standing questions in astrophysics.” 

Most of the matter in a black hole–neutron star merger is expected to be sucked up by the black hole within a millisecond of the merger, and other matter that is not flung away in the merger is likely to form an extremely dense, thin, donut-shaped halo of matter. 

The thin, hot disk of matter that is bound by the black hole is expected to form within about 10 milliseconds of the merger, and to be concentrated within about 15 to 70 miles of it, the simulations showed. This first 10 milliseconds appears to be key in the long-term evolution of these disks.

Over timescales ranging from tens of milliseconds to several seconds, the hot disk spreads out and launches more matter into space. “A number of physical processes – from magnetic fields to particle interactions and nuclear reactions – combine in complex ways to drive the evolution of the disk,” said Rodrigo Fernández, an assistant professor of physics at the University of Alberta in Canada who led one of the studies.

Simulations carried out on NERSC’s Edison supercomputer were crucial in understanding how the disk ejects matter and in providing clues for how to observe this matter, said Fernández, a former UC Berkeley postdoctoral researcher.

What’s next?

Eventually, it may be possible for astronomers scanning the night sky to find the “needle in a haystack” of radioactive kilonovae from neutron star mergers that had been missed in the LIGO data, Kasen said.

“With improved models, we are better able to tell the observers exactly which flashes of light are the signals they are looking for,” he said. Kasen is also working to build increasingly sophisticated models of neutron star mergers and supernovae through his involvement in the DOE Exascale Computing Project.

As the sensitivity of gravitational-wave detectors improves, Foucart said, it may be possible to detect a continuous signal produced by even a tiny bump on the surface of a neutron star, for example, or signals from theorized one-dimensional objects known as cosmic strings. 

“This could also allow us to observe events that we have not even imagined,” he said.

NERSC is a DOE Office of Science User Facility.

Researchers from Washington State University, Cornell University, the University of Toronto in Canada, the University of Alberta in Canada, the California Institute of Technology, and Michigan State University also participated in this research. This work was supported by the DOE Office of Science; UC Office of the President; NASA; the UC Berkeley-Rose Hills Foundation; NSERC Canada; the National Science Foundation; and Sherman Fairchild Foundation.

# # #

Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel Prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

X
X
X
  • Filters

  • × Clear Filters

Nanotechnology Gives Green Energy a Green Color

Solar panels have tremendous potential to provide affordable renewable energy, but many people see traditional black and blue panels as an eyesore. Architects, homeowners and city planners may be more open to the technology if they could install colorful, efficient solar panels, and a new study, published this week in Applied Physics Letters, brings us one step closer. Researchers have developed a method for imprinting existing solar panels with silicon nanopatterns that scatter green light back toward an observer.

New 3-D Simulations Show How Galactic Centers Cool Their Jets

Scientists at Berkeley Lab and Purdue University developed new theories and 3-D simulations to explain what's at work in the mysterious jets of energy and matter beaming from the center of galaxies at nearly the speed of light.

Are Your Tweets Feeling Well?

Study finds opinion and emotion in tweets change when you get sick, a method public health workers could use to track health trends.

"Getting to 80%" on Energy Cutbacks Cannot Occur Unless Behaviors Change

California's plan to cut energy consumption by 80 percent by 2050 cannot be achieved with current proposed policy changes because most solutions focus on changing technologies rather than changing behavior, a new UC Davis study suggests.

New Battery Material Goes with the Flow

Scientists at the U.S. Department of Energy's (DOE) Argonne National Laboratory have engineered a new material to be used in redox flow batteries, which are particularly useful for storing electricity for the grid. The material consists of carefully structured molecules designed to be particularly electrochemically stable in order to prevent the battery from losing energy to unwanted reactions.

Simulation Demonstrates How Exposure to Plasma Makes Carbon Nanotubes Grow

PPPL research performed with collaborators from Princeton University and the Institute for Advanced Computational Science at the State University of New York at Stony Brook has shown how plasma causes exceptionally strong, microscopic structures known as carbon nanotubes to grow.

Night Vision for Bird- & Bat-Friendly Offshore Wind Power

The ThermalTracker software analyzes video with night vision, the same technology that helps soldiers see in the dark, to help birds and bats near offshore wind turbines.

Drone Tech Offers New Ways to Manage Climate Change

An innovation providing key clues to how humans might manage forests and cities to cool the planet is taking flight. Cornell researchers are using drone technology to more accurately measure surface reflectivity on the landscape, a technological advance that could offer a new way to manage climate change.

Energy Efficiency Takes a 'Village'

The city of the future could start with a village - Missouri University of Science and Technology's Solar Village, to be exact. S&T researchers will study the Solar Village and its residents as their living laboratory over the next three years thanks to an $800,000 grant from the National Institute of Food and Agriculture, funded as part of the National Science Foundation's Cyber-Physical System initiative. The research team is led by Dr. Simone Silvestri, principal investigator and assistant professor of computer science, and Dr. Denise Baker, co-principal investigator and assistant professor of psychological science

Updated Computer Code Improves Prediction of Energetic Particle Motion in Plasma Experiments

A computer code used by physicists around the world to analyze and predict tokamak experiments can now approximate the behavior of highly energetic atomic nuclei, or ions, in fusion plasmas more accurately than ever.


  • Filters

  • × Clear Filters

Southern Research to Play Key Role in Low Cost Carbon Fiber Project

Southern Research's Energy & Environment division (E&E) will participate as a subcontractor to WRI to provide renewable acrylonitrile -- the key raw material needed to produce the highest quality carbon fibers -- produced from biomass-derived second generation sugars.

Newly Upgraded Laser Allows Scientists to Peer Further Into the Extreme Universe at SLAC's LCLS

Scientists at the Department of Energy's SLAC National Accelerator Laboratory recently upgraded a powerful optical laser system used to create shockwaves that generate high-pressure conditions like those found within planetary interiors. The laser system now delivers three times more energy for experiments with SLAC's ultrabright X-ray laser, providing a more powerful tool for probing extreme states of matter in our universe.

Three Brookhaven Lab Scientists Selected to Receive Early Career Research Program Funding

Three scientists at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory have been selected by DOE's Office of Science to receive significant research funding through its Early Career Research Program.

Upcoming 232nd ECS Meeting to Feature International Energy Summit, Nobel Laureate Lecture

The 232nd ECS Meeting will include 49 topical symposia and over 2,300 technical presentations, including the 7th International Electrochemical Energy Summit, the Society's inaugural OpenCon and Hack Day events, and plenary lecture delivered by former U.S. Secretary of Energy and Nobel Prize Laureate Steven Chu.

PNNL Scientist Jiwen Fan Receives DOE Early Career Research Award

Jiwen Fan of the Department of Energy's Pacific Northwest National Laboratory has been selected to receive a 2017 Early Career Research Program award from the U.S. Department of Energy. Fan will use the award to study severe thunderstorms in the central United States - storms that produce large hail, damaging winds, tornadoes, and torrential rainfall.

Three SLAC Scientists Receive DOE Early Career Research Grants

Three scientists at the Department of Energy's SLAC National Accelerator Laboratory will receive DOE Early Career Research Program grants for research to find evidence of cosmic inflation, understand how plasmas excite particles to high energies and develop a way to accelerate particles in much shorter distances with terahertz radiation.

Four ORNL Researchers Receive DOE Early Career Funding Awards

Four Oak Ridge National Laboratory researchers specializing in nuclear physics, fusion energy, advanced materials and environmental science are among 59 recipients of Department of Energy's Office of Science Early Career Research Program awards.

Missouri S&T Professor Earns Patent for Energy Storage Technology

ceramic engineering professor at Missouri University of Science and Technology has received a federal patent for his latest innovation, a multi-layer ceramic capacitor that could help boost energy storage in applications ranging from pulse power devices to military hardware.

James Peery Named Chief Scientist of the Global Security Directorate at Oak Ridge National Laboratory

James Peery, who has led critical national security programs at Sandia National Laboratories and Los Alamos National Laboratory, has been selected as the chief scientist of the Global Security Directorate at Oak Ridge National Laboratory.

Franklin Fuller and Cornelius Gati Named 2017 Panofsky Fellows at SLAC

Franklin Fuller and Cornelius Gati have been awarded 2017 Panofsky Fellowships by the Department of Energy's SLAC National Accelerator Laboratory, where they will work over the next five years to get significantly more information about how catalysts work and develop new and improved biological imaging methods.


  • Filters

  • × Clear Filters

Physicists Move Closer to Listening in on Sub-Atomic Conversation

Calculations of a subatomic particle called the sigma provide insight into the communication between subatomic particles deep inside the heart of matter.

Meet the Director: Chuck Black

This is a continuing profile series on the directors of the Department of Energy (DOE) Office of Science User Facilities. These scientists lead a variety of research institutions that provide researchers with the most advanced tools of modern science including accelerators, colliders, supercomputers, light sources and neutron sources, as well as facilities for studying the nano world, the environment, and the atmosphere.

Making an Ultra-small Silicon "Chip"

A new polymer, created with a structure inspired by crystalline silicon, may make it easier to build better computers and solar cells.

How to Keep a Vital Diagnostic Isotope in Stock

Researchers succeed in producing larger quantities of a long-lived radioisotope, titanium-44, that generates a needed isotope, scandium-44g, on demand.

When Strontium Is Away, Iridium Comes Out to Play

Developing a highly active and acid-stable catalyst for water splitting could significantly impact solar energy technologies.

On Track Towards a Zika Virus Vaccine

Antibody's molecular structure reveals how it recognizes the Zika virus

Quantum Computing Building Blocks

Scientists invented an approach to creating ordered patterns of nitrogen-vacancy centers in diamonds, a promising approach to storing and computing quantum data.

Scientists Program Yeast to Turn Plant Sugars into Biodiesel

Redox metabolism was engineered in Yarrowia lipolytica to increase the availability of reducing molecules needed for lipid production.

Soils Could Release Much More Carbon than Expected as Climate Warms

Deeper soil layers are more sensitive to warming than previously thought.

Weaving a Fermented Path to Nylons

Microbial enzymes create precursors of nylon while avoiding harsh chemicals and energy-demanding heat.


Spotlight

Saturday May 20, 2017, 12:05 PM

Rensselaer Polytechnic Institute Graduates Urged to Embrace Change at 211th Commencement

Rensselaer Polytechnic Institute (RPI)

Monday May 15, 2017, 01:05 PM

ORNL, University of Tennessee Launch New Doctoral Program in Data Science

Oak Ridge National Laboratory

Friday April 07, 2017, 11:05 AM

Champions in Science: Profile of Jonathan Kirzner

Department of Energy, Office of Science

Wednesday April 05, 2017, 12:05 PM

High-Schooler Solves College-Level Security Puzzle From Argonne, Sparks Interest in Career

Argonne National Laboratory

Tuesday March 28, 2017, 12:05 PM

Champions in Science: Profile of Jenica Jacobi

Department of Energy, Office of Science

Friday March 24, 2017, 10:40 AM

Great Neck South High School Wins Regional Science Bowl at Brookhaven Lab

Brookhaven National Laboratory

Wednesday February 15, 2017, 04:05 PM

Middle Schoolers Test Their Knowledge at Science Bowl Competition

Argonne National Laboratory

Friday January 27, 2017, 04:00 PM

Haslam Visits ORNL to Highlight State's Role in Discovering Tennessine

Oak Ridge National Laboratory

Tuesday November 08, 2016, 12:05 PM

Internship Program Helps Foster Development of Future Nuclear Scientists

Oak Ridge National Laboratory

Friday May 13, 2016, 04:05 PM

More Than 12,000 Explore Jefferson Lab During April 30 Open House

Thomas Jefferson National Accelerator Facility

Monday April 25, 2016, 05:05 PM

Giving Back to National Science Bowl

Ames Laboratory

Friday March 25, 2016, 12:05 PM

NMSU Undergrad Tackles 3D Particle Scattering Animations After Receiving JSA Research Assistantship

Thomas Jefferson National Accelerator Facility

Tuesday February 02, 2016, 10:05 AM

Shannon Greco: A Self-Described "STEM Education Zealot"

Princeton Plasma Physics Laboratory

Monday November 16, 2015, 04:05 PM

Rare Earths for Life: An 85th Birthday Visit with Mr. Rare Earth

Ames Laboratory

Tuesday October 20, 2015, 01:05 PM

Meet Robert Palomino: 'Give Everything a Shot!'

Brookhaven National Laboratory

Tuesday April 22, 2014, 11:30 AM

University of Utah Makes Solar Accessible

University of Utah

Wednesday March 06, 2013, 03:40 PM

Student Innovator at Rensselaer Polytechnic Institute Seeks Brighter, Smarter, and More Efficient LEDs

Rensselaer Polytechnic Institute (RPI)

Friday November 16, 2012, 10:00 AM

Texas Tech Energy Commerce Students, Community Light up Tent City

Texas Tech University

Wednesday November 23, 2011, 10:45 AM

Don't Get 'Frosted' Over Heating Your Home This Winter

Temple University

Wednesday July 06, 2011, 06:00 PM

New Research Center To Tackle Critical Challenges Related to Aircraft Design, Wind Energy, Smart Buildings

Rensselaer Polytechnic Institute (RPI)

Friday April 22, 2011, 09:00 AM

First Polymer Solar-Thermal Device Heats Home, Saves Money

Wake Forest University

Friday April 15, 2011, 12:25 PM

Like Superman, American University Will Get Its Energy from the Sun

American University

Thursday February 10, 2011, 05:00 PM

ARRA Grant to Help Fund Seminary Building Green Roof

University of Chicago

Tuesday December 07, 2010, 05:00 PM

UC San Diego Installing 2.8 Megawatt Fuel Cell to Anchor Energy Innovation Park

University of California San Diego

Monday November 01, 2010, 12:50 PM

Rensselaer Smart Lighting Engineering Research Center Announces First Deployment of New Technology on Campus

Rensselaer Polytechnic Institute (RPI)

Friday September 10, 2010, 12:40 PM

Ithaca College Will Host Regional Clean Energy Summit

Ithaca College

Tuesday July 27, 2010, 10:30 AM

Texas Governor Announces $8.4 Million Award to Create Renewable Energy Institute

Texas Tech University

Friday May 07, 2010, 04:20 PM

Creighton University to Offer New Alternative Energy Program

Creighton University

Wednesday May 05, 2010, 09:30 AM

National Engineering Program Seeks Subject Matter Experts in Energy

JETS Junior Engineering Technical Society

Wednesday April 21, 2010, 12:30 PM

Students Using Solar Power To Create Sustainable Solutions for Haiti, Peru

Rensselaer Polytechnic Institute (RPI)

Wednesday March 03, 2010, 07:00 PM

Helping Hydrogen: Student Inventor Tackles Challenge of Hydrogen Storage

Rensselaer Polytechnic Institute (RPI)

Thursday February 04, 2010, 02:00 PM

Turning Exercise into Electricity

Furman University

Thursday November 12, 2009, 12:45 PM

Campus Leaders Showing the Way to a Sustainable, Clean Energy Future

National Wildlife Federation (NWF)

Tuesday November 03, 2009, 04:20 PM

Furman University Receives $2.5 Million DOE Grant for Geothermal Project

Furman University

Thursday September 17, 2009, 02:45 PM

Could Sorghum Become a Significant Alternative Fuel Source?

Salisbury University

Wednesday September 16, 2009, 11:15 AM

Students Navigating the Hudson River With Hydrogen Fuel Cells

Rensselaer Polytechnic Institute (RPI)

Wednesday September 16, 2009, 10:00 AM

College Presidents Flock to D.C., Urge Senate to Pass Clean Energy Bill

National Wildlife Federation (NWF)

Wednesday July 01, 2009, 04:15 PM

Northeastern Announces New Professional Master's in Energy Systems

Northeastern University

Friday October 12, 2007, 09:35 AM

Kansas Rural Schools To Receive Wind Turbines

Kansas State University

Thursday August 17, 2006, 05:30 PM

High Gas Prices Here to Stay, Says Engineering Professor

Rowan University

Wednesday May 17, 2006, 06:45 PM

Time Use Expert's 7-Year Fight for Better Gas Mileage

University of Maryland, College Park





Showing results

0-4 Of 2215