Space

February 13, 2013

NASA’s Chandra suggests rare explosion created our galaxyís youngest black hole

nasa-chandr
New data from NASA’s Chandra X-ray Observatory suggest a highly distorted supernova remnant may contain the most recent black hole formed in the Milky Way galaxy. The remnant appears to be the product of a rare explosion in which matter is ejected at high speeds along the poles of a rotating star.

The remnant, called W49B, is about a thousand years old as seen from Earth and located about 26,000 light-years away. “W49B is the first of its kind to be discovered in the galaxy,” said Laura Lopez, who led the study at the Massachusetts Institute of Technology. “It appears its parent star ended its life in a way that most others don’t.”

Usually when a massive star runs out of fuel, the central region of the star collapses, triggering a chain of events that quickly culminate in a supernova explosion. Most of these explosions are generally symmetrical, with the stellar material blasting away more or less evenly in all directions.

However, in the W49B supernova, material near the poles of the doomed rotating star was ejected at a much higher speed than material emanating from its equator. Jets shooting away from the star’s poles mainly shaped the supernova explosion and its aftermath.

The remnant now glows brightly in X-rays and other wavelengths, offering the evidence for a peculiar explosion. By tracing the distribution and amounts of different elements in the stellar debris field, researchers were able to compare the Chandra data to theoretical models of how a star explodes. For example, they found iron in only half of the remnant while other elements such as sulfur and silicon were spread throughout. This matches predictions for an asymmetric explosion.

“In addition to its unusual signature of elements, W49B also is much more elongated and elliptical than most other remnants,” said co-author Enrico Ramirez-Ruiz of the University of California at Santa Cruz.
“This is seen in X-rays and several other wavelengths and points to an unusual demise for this star.”

Because supernova explosions are not well understood, astronomers want to study extreme cases like the one that produced W49B. The relative proximity of W49B also makes it extremely useful for detailed study.

The authors examined what sort of compact object the supernova explosion left behind. Most of the time, massive stars that collapse into supernovas leave a dense, spinning core called a neutron star.

Astronomers often can detect neutron stars through their X-ray or radio pulses, although sometimes an X-ray source is seen without pulsations. A careful search of the Chandra data revealed no evidence for a neutron star. The lack of such evidence implies a black hole may have formed.

“It’s a bit circumstantial, but we have intriguing evidence the W49B supernova also created a black hole,” said co-author Daniel Castro, also of MIT. “If that is the case, we have a rare opportunity to study a supernova responsible for creating a young black hole.”

Supernova explosions driven by jets like the one in W49B have been linked to gamma-ray bursts (GRBs) in other objects. GRBs, which have been seen only in distant galaxies, also are thought to mark the birth of a black hole. There is no evidence the W49B supernova produced a GRB, but it may have properties – including being jet-driven and possibly forming a black hole – that overlap with those of a GRB.

The new results on W49B, which were based on about two-and-a-half days of Chandra observing time, appear in a paper in Sunday’s issue of the Astrophysical Journal. The other co-author was Sarah Pearson from the University of Copenhagen in Denmark.

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 controls Chandra’s science and flight operations from Cambridge, Mass.




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


 
 

 
NASA/JPL-Caltech image

NASA’s Mars spacecraft maneuvers to prepare for close comet flyby

NASA/JPL-Caltech image This graphic depicts the orbit of comet C/2013 A1 Siding Spring as it swings around the sun in 2014. On Oct. 19, the comet will have a very close pass at Mars. Its nucleus will miss Mars by about 82,000 m...
 
 
Image courtesy of U.S. Bureau of Reclamation

Satellite study reveals parched U.S. West using up underground water

Image courtesy of U.S. Bureau of Reclamation The Colorado River Basin lost nearly 53 million acre feet of freshwater over the past nine years, according to a new study based on data from NASA’s GRACE mission. This is almost d...
 
 

NASA selects contract for mission support services at Ames

NASA has selected Wyle Laboratories, Inc., Houston, to support NASA’s flight programs and mission projects, providing support for multiple sustained project management, research and technology development capabilities that encompass all phases of mission and project lifecycles at the agency’s Ames Research Center in Moffett Field, Calif. The cost-plus-fixed-fee hybrid contract has a...
 

 
NASA, ESA, G. Bacon (STScI) and N. Madhusudhan (UC) image

Hubble finds three surprisingly dry exoplanets

NASA, ESA, G. Bacon (STScI) and N. Madhusudhan (UC) image This is an artistic illustration of the gas giant planet HD 209458b in the constellation Pegasus. To the surprise of astronomers, they have found much less water vapor i...
 
 
Air Force photograph

Budget cuts, growing threats affect space operations

Air Force photograph The Advanced Extremely High Frequency, or AEHF, system is a joint service satellite communications system that provides survivable, global, secure, protected and jam-resistant communications for high-priori...
 
 

NASA partners punctuate summer with spacecraft development advances

Spacecraft and rocket development is on pace this summer for NASA’s aerospace industry partners for the agency’s Commercial Crew Program as they progress through systems testing, review boards and quarterly sessions under their† Space Act Agreements with the agency. NASA engineers and specialists continue their review of the progress as the agency and partners move...
 




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>