Los Alamos team aids understanding of astrophysical mystery

September 8, 2011—New Hubble Space Telescope movies of gas jets from stars reveal their fast-changing inner structures. Thanks to the Los Alamos RAGE computer code and a series of supercomputers, a research team now understands more about how observed shock waves, knots, and filamentary structures in these supersonic glowing jets evolve in the stellar environment.

The success of this understanding lies in the combination of simulations, laboratory experiments, and astrophysical observations. This three pronged approach was originally utilized in the Astrophysical Journal paper (Vol 705, 1073, 2009). Bernie Wilde of Los Alamos, and Rob Coker (now at NASA) worked on the design and simulation of these counterparts. More recently, Wilde and Melissa Douglas have worked together to help design and simulate what happens when a particular kind of shock wave, called a bow shock, moves through multiple environments with “clumps” of denser hydrogen.

Now, after more lab experiments, supercomputer analysis and time-lapse movies from the images captured by Hubble, the team has laid out its concept of what’s happening in these massive events. The results were reported in the 20 July 2011 issue of the Astrophysical Journal

"The interstellar medium through which the jets propagate is not homogeneous," said Douglas. "The latest experiments are the laboratory analogue of astrophysical bow shocks interacting with these clumpy environments," she said.

The experiments and simulations exhibit a remarkable resemblance to some of the Hubble images in the journal article, noted Douglas. "They show bow shocks, knots, and filamentary structure. These experiments and simulations will be used along with the observations to gain physical understanding of the interactions occurring within such chaotic, complex systems."

Wilde and the latest team member, Kris Yirak are currently at the OMEGA Laser Facility in Rochester, New York, continuing work with the team, which is led by astronomer Patrick Hartigan of Rice University.

A RAGE simulation of a turbulent jet is part of a LANL movie narrated by journalist Miles O’Brien that will soon be showing at the Bradbury Science Museum.

The Hubble Space Telescope is a project of international cooperation between the European Space Agency and NASA. The international team of scientists in this study consists of

• Patrick Hartigan (Rice University, Texas)
• Adam Frank (University of Rochester, New York)
• John Foster (Atomic Weapons Establishment, Aldermaston, Berkshire)
• Paula Rosen (Atomic Weapons Establishment, Aldermaston, Berkshire)
• Bernie Wilde (Los Alamos National Laboratory, New Mexico)
• Rob Coker (Los Alamos National Laboratory, New Mexico)
• Melissa Douglas (Los Alamos National Laboratory, New Mexico)
• Brent Blue (General Atomics, San Diego, California)
• Freddy Hansen (General Atomics, San Diego, California).

Link: http://www.spacetelescope.org/news/heic1113/