Though several models predict this behavior and evidence from supernovae points in this direction, actually observations of such pre-explosion outbursts have been rare. In new research led by Dr. Eran Ofek of the Weizmann Institute, scientists found such an outburst taking place a short time – just one month – before a massive star underwent a supernova explosion.
The findings, which recently appeared in Nature, help to clarify the series of events leading up to the supernova, as well as providing insight into the processes taking place in the cores of such massive stars as they progress toward the final stage of their lives.
Ofek, a member of the Institute's Particle Physics and Astrophysics Department, is a participant in the Palomar Transient Factory (PTF) project (led by Prof. Shri Kulkarni of the California Institute of Technology), which searches the skies for supernova events using telescopes at the Palomar Observatory in California. He and a research team from Israel, the UK and the US decided to investigate whether outbursts could be connected to later supernovae by combing for evidence of them in observations that predated PTF supernova sightings, using tools developed by Dr. Mark Sullivan of the University of Southampton.
The fact that they found such an outburst occurring just a little over a month before the onset of the supernova explosion was something of a surprise, but the timing and mass of the ejected material helped them to validate a particular model that predicts this type of pre-explosion event. A statistical analysis showed that there was only a 0.1% chance that the outburst and supernova were unrelated occurrences.
The exploding star, known as a type IIn supernova, began as a massive star, at least 8 times the mass of our sun. As such a star ages, the internal nuclear fusion that keeps it going produces heavier and heavier elements – until its core is mostly iron. At that point, the weighty core quickly collapses inward and the star explodes.
The violence and mass of the pre-explosion outburst they found, says Ofek, point to its source in the star's core. The material is speedily ejected from the core straight through the star's surface by the excitation of gravity waves. The researchers believe that continued research in this direction will show such mini-explosions to be the rule for this type of supernova.
Also participating in this research were Prof. Avishay Gal-Yam, Dr. Ofer Yaron and Iair Arcavi of the Institute's Particle Physics and Astrophysics Department, and Prof. Nir Shaviv of the Hebrew University of Jerusalem.
Prof. Avishay Gal-Yam's research is supported by the Helen and Martin Kimmel Award for Innovative Investigation; the Nella and Leon Benoziyo Center for Astrophysics; and the Lord Sieff of Brimpton Memorial Fund.
Dr. Eran Ofek's research is supported by the Willner Family Leadership Institute. Dr. Ofek is the incumbent of the Arye and Ido Dissentshik Career Development Chair.
The Weizmann Institute of Science in Rehovot, Israel, is one of the world's top-ranking multidisciplinary research institutions. Noted for its wide-ranging exploration of the natural and exact sciences, the Institute is home to 2,700 scientists, students, technicians and supporting staff. Institute research efforts include the search for new ways of fighting disease and hunger, examining leading questions in mathematics and computer science, probing the physics of matter and the universe, creating novel materials and developing new strategies for protecting the environment.
Weizmann Institute news releases are posted on the World Wide Web at http://wis-wander.weizmann.ac.il, and are also available at http://www.eurekalert.org.
Yivsam Azgad | EurekAlert!
Identifying New Sources of Turbulence in Spherical Tokamaks
30.11.2015 | Princeton Plasma Physics Laboratory
Graphene microphone outperforms traditional nickel and offers ultrasonic reach
27.11.2015 | Institute of Physics
Before the fluid of the middle ear drains and sound waves penetrate for the first time, the inner ear cells of newborn rodents practice for their big debut. Researchers at Johns Hopkins report they have figured out the molecular chain of events that enables the cells to make “sounds” on their own, essentially “practicing” their ability to process sounds in the world around them.
The researchers, who describe their experiments in the Dec. 3 edition of the journal Cell, show how hair cells in the inner ear can be activated in the absence...
Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.
Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...
The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...
Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.
In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...
In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.
Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...
30.11.2015 | Event News
25.11.2015 | Event News
17.11.2015 | Event News
30.11.2015 | Trade Fair News
30.11.2015 | Trade Fair News
30.11.2015 | Trade Fair News