Supernova caught in the act

December 14, 2011

The earliest detection ever of a Type Ia supernova has led to unparalleled observations of the initial stages of the supernova and characterization of the nature of the stars that formed it.

On August 24, 2011, astronomers discovered a nearby Type Ia supernova--the earliest detection ever--with help from a machine-based real-time classification system. The early detection and close proximity of the stars set the stage for unprecedented observation of the initial stages of a Type Ia supernova. Two articles describing the exploding star and details about the companion star are published in the December 15 issue of the journal Nature.

"The National Science Foundation (NSF)-sponsored work we did in Berkeley on real-time classification of astronomical time-series helped with this large needle-in-a-haystack problem: we have 1.5 million candidates a night, of which only a few are interesting new transients," said Josh Bloom, a co-author on both articles referring to objects that change in the night sky. "Our machine learning-based codes raised the supernova candidate event to the top of list of possible new transients."

Supernovae are extraordinarily bright stellar explosions that signal the death of a star and there are several different types. Type Ia supernovae have similarities that allow astronomers to use them as standards when comparing the distances of objects in the sky, however little is known about the stars that produce them or how they behave when they explode. Models of Type Ia supernovae assume they are formed from two-star systems in which a very dense, very small star called a white dwarf orbits a companion.

This supernova, named 2011fe, occurred in the Pinwheel galaxy, which is located in the "Big Dipper" within the Ursa Major constellation. Early detection gave astronomers the extraordinary opportunity to observe the evolution of the brightness and spectra of the energy emitted from the explosion over time. Based on these data, researchers were able to approximate how big the star was and when it exploded, in addition to details about the companion star in the system.

NSF's Cyber-Enabled Discovery and Innovation (CDI) program, with the goal of building computational tools with concrete scientific returns in mind, supported the computational framework that enabled this discovery. The framework could form the foundation for applications in other fields with similar demands and constraints, such as high-frequency financial data, robotics, medical signal monitoring, geophysics, weather and particle physics.

This CDI grant was jointly supported by astronomy, computer science, and mathematical sciences divisions of NSF. Tom Russell of NSF's Office of Integrative Activities commented, "The unprecedented rapid detection and early observation of a supernova is a wonderful example of a main theme of the interdisciplinary CDI program - 'From Data to Knowledge: enhancing human cognition and generating new knowledge from a wealth of digital data.' In 2012, NSF is continuing its emphasis on this theme through the Data-Enabled Science component of the Cyberinfrastructure Framework for 21st Century Science and Engineering (CIF21) portfolio of activities."

"This event might have been missed or not detected right away--maybe even a week later, if we only relied on human eyes to do the search," continued Bloom. "No one has done this type of search on this scale before, and as new astronomical surveys come online in the next few years, this framework for extracting novel science from large amounts of data will become increasingly important."

Methods developed within the 'Data to Knowledge' theme of the CDI program apply scientific knowledge to enable automated processing of massive data streams, while the Palomar Transient Factory (PTF) is a wide-field survey that scans the skies for transients. This made Bloom's CDI project and the PTF a natural collaboration.

"We are moving into the era of peta-scale astronomical surveys, of which the NSF-supported Palomar Transient Factory is an early example," said Nigel Sharp, program director for NSF's division of Astronomical Sciences. "This supernova result is an excellent illustration of the power of machine learning to assist not only with data collection and reduction, but with the tasks of discovery and inference as well."

Shri Kulkarni, an astronomer at University of California, Berkeley, and leader of the PTF also commented on the effectiveness of this collaboration and the power of teamwork, "The Palomar Transient Factory has been an amazing machine. The rapid discovery of the supernova in the Pinwheel galaxy (Messier 101) is a testament to the great teamwork (spread over a half a dozen institutions) that has made rapid classification of supernova possible within the same night."

National Science Foundation

Related Supernova Articles from Brightsurf:

Scientists discover supernova that outshines all others
A supernova at least twice as bright and energetic, and likely much more massive than any yet recorded has been identified by an international team of astronomers, led by the University of Birmingham.

Supernova observation first of its kind using NASA satellite
Their research, detailed in the Monthly Notices of the Royal Astronomical Society, represents the first published findings about a supernova observed using TESS, and add new insights to long-held theories about the elements left behind after a white dwarf star explodes into a supernova.

Astronomers find possible elusive star behind supernova
Astronomers may have finally found a doomed star that seemed to have avoided detection before its explosive death.

Stellar thief is the surviving companion to a supernova
Hubble found the most compelling evidence that some supernovas originate in double-star systems.

Supernova may have 'burped' before exploding
Only by increasing the rate at which telescopes monitor the sky has it been possible to catch more Fast-Evolving Luminous Transients (FELTs) and begin to understand them.

An unusual white dwarf may be a supernova leftover
Astronomers have identified a white dwarf star in our galaxy that may be the leftover remains of a recently discovered type of supernova.

Researchers show how to make your own supernova
Researchers from the University of Oxford are using the largest, most intense lasers on the planet, to for the first time, show the general public how to recreate the effects of supernovae, in a laboratory.

The big star that couldn't become a supernova
For the first time in history, astronomers have been able to watch as a dying star was reborn as a black hole.

Seeing quadruple: Four images of the same supernova, a rare find
Galaxies bend light through an effect called gravitational lensing that helps astronomers peer deeper into the cosmos.

Explosive material: The making of a supernova
Pre-supernova stars may show signs of instability for months before the big explosion

Read More: Supernova News and Supernova Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to