Space

December 4, 2013

Supernova blast provides clues to determining age of binary star system

Illustration of Circinus X-1, an X-ray binary star system.

Data from NASA’s Chandra X-ray Observatory has revealed faint remnants of a supernova explosion and helped researchers determine Circinus X-1 – an X-ray binary – is the youngest of this class of astronomical objects found to date.

As the name suggests, X-ray binaries are star systems made up of two parts: a compact stellar remnant – either a neutron star or a black hole; and a companion star – a normal star like our sun. As they orbit one another, the neutron star or black hole pulls in gas from the companion star. This heats the gas to millions of degrees, producing intense X-ray radiation and making these star systems some of the brightest X-ray sources in the sky.

Sebastian Heinz and his team at the University of Wisconsin-Madison discovered Circinus X-1 is less than 4,600 years old, making it the youngest X-ray binary system ever seen. This discovery, made in parallel with a radio telescope in Australia, provides scientists unique insight into the formation of neutron stars and supernovas, and the effect of the supernova’s explosion on a nearby companion star.

“X-ray binaries provide us with opportunities to study matter under extreme conditions that would be impossible to recreate in a laboratory,” Heinz said. “For the first time, we can study a newly minted neutron star in an X-ray binary system.”

Astronomers have detected hundreds of X-ray binaries throughout the Milky Way and other nearby galaxies. However, these older X-ray binaries, with ages typically measured in millions of years, only reveal information about what happens much later in the evolution of these systems.

“It’s critical that we see what these X-ray binaries are doing at all stages of their lives,” said co-author Paul Sell, also of UW. “Circinus X-1 is showing us what happens in a cosmic blink of an eye after one of these objects is born.”

To determine the age of Circinus X-1, the team of astronomers needed to examine the material around the orbiting pair of stars. However, the overwhelming brightness of the neutron star made it too difficult for researchers to observe that interstellar gas. The team recently caught a break, when they observed the neutron star in a very faint state — dim enough for scientists to detect the X-rays from the supernova shock wave that plowed through the surrounding interstellar gas.

“Since the supernova was triggered by the formation of the neutron star, our limit on the age of the supernova remnant also limits the age of the neutron star in Circinus X-1,” said co-author Robert Fender of the University of Oxford in the U.K.

The youth of Circinus X-1 helps explain its wild swings in brightness and the highly unusual orbit of its two stars, which had puzzled astronomers for years. The orbit is very eccentric – non-circular – and the period during which the two stars orbit each other is decreasing by several minutes every year. This is exactly what is expected for a young X-ray binary disrupted by a supernova explosion before the gravitational pull of the stars on each other has had time to circularize and stabilize the orbit.

Previous observations with other telescopes indicated the magnetic field of the neutron star in Circinus X-1 is weak. That, in addition to the star system’s young age, has led to two possible theories: either a neutron star can be born with a weak magnetic field, or it can quickly become de-magnetized as it pulls material from its companion star onto itself. Neither conclusion was expected from existing theories of neutron star evolution.

In our galaxy, the only other established X-ray binary within a supernova remnant is SS 433, which is between 10,000 and 100,000 years old, and behaves in many ways like an older version of Circinus X-1. Two other candidate X-ray binaries in nearby galaxies have ages similar to SS 433.

In addition to the Chandra data, radio observations from the Australia Telescope Compact Array were critical in these findings. A paper describing these results is available online and appears in the Dec. 3 issue of The Astrophysical Journal.

NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Mass., controls Chandra’s science and flight operations.




All of this week's top headlines to your email every Friday.


 
 

 
Image courtesy of NASA Goddard

NASA’s OSIRIS-REx mission passes critical milestone

Image courtesy of NASA Goddard Artist concept of OSIRIS-REx, the first U.S. mission to return samples from an asteroid to Earth. NASA’s groundbreaking science mission to retrieve a sample from an ancient space rock has mo...
 
 
Lockheed Martin photograph

Lockheed Martin begins final assembly of NASA’s OSIRIS-REx spacecraft

Lockheed Martin photograph In a clean room facility near Denver, Lockheed Martin technicians began assembling NASA’s OSIRIS-Rex spacecraft that will collect samples of an asteroid. In a clean room facility near Denver, Lo...
 
 
ball-CDR

Ball Aerospace GEMS instrument passes critical design review

The Ball Aerospace air quality sensor being built for the Korea Aerospace Research Institute under South Korea’s National Institute of Environmental Research in the Ministry of Environment has passed a major milestone tow...
 

 

Year in space starts for one American, one Russian

Three crew members representing the United States and Russia are on their way to the International Space Station after launching from the Baikonur Cosmodrome in Kazakhstan at 3:42 p.m., EDT, March 27. NASA astronaut Scott Kelly and Russian Federal Space Agency (Roscosmos) cosmonaut Mikhail Kornienko will spend about a year living and working aboard the...
 
 
NASA photograph

Orion parachute testing conducted at AEDC NFAC facility

AEDC engineers were part of a test team that performed wind tunnel testing on the parachutes for NASA Orion spacecraft in January. The test team also consisted of NASA, Airborne Systems, Jacobs Engineering and NFAC personnel. P...
 
 

Ninth Boeing GPS IIF reaches orbit, sends first signals

Boeing Global Positioning System (GPS) IIF satellites are steadily replenishing the orbiting constellation, continuing to improve reliability and accuracy for users around the world. The ninth GPS IIF reached orbit about three hours, 20 minutes after launching today aboard a United Launch Alliance (ULA) Delta IV rocket from Cape Canaveral Air Force Station, Fla., and...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>