Astronomy Now Online

Top Stories

Galaxy "skid marks" reveal collision history

...the discovery of new tidal debris stripped away from merging galaxies contains the full collision history, equivalent to being able to trace the skid marks on the road after a car crash...

read more

Astronomical whirling dervishes hide their
age well

...Estimates of the age of some millisecond pulsars are out by a factor of ten, according to new research...

read more

Supermassive black holes put on weight

...New computer modelling has found that the black hole at the heart of M87 is as much as three times more massive than previously thought...

read more

Spaceflight Now +

Subscribe to Spaceflight Now Plus for access to our extensive video collections!
How do I sign up?
Video archive

STS-120 day 2 highlights

Flight Day 2 of Discovery's mission focused on heat shield inspections. This movie shows the day's highlights.


STS-120 day 1 highlights

The highlights from shuttle Discovery's launch day are packaged into this movie.


STS-118: Highlights

The STS-118 crew, including Barbara Morgan, narrates its mission highlights film and answers questions in this post-flight presentation.

 Full presentation
 Mission film

STS-120: Rollout to pad

Space shuttle Discovery rolls out of the Vehicle Assembly Building and travels to launch pad 39A for its STS-120 mission.


Dawn leaves Earth

NASA's Dawn space probe launches aboard a Delta 2-Heavy rocket from Cape Canaveral to explore two worlds in the asteroid belt.

 Full coverage

Dawn: Launch preview

These briefings preview the launch and science objectives of NASA's Dawn asteroid orbiter.

 Launch | Science

Become a subscriber
More video

Supernova remnant is an unusual suspect



Posted: 10 June, 2009

An unusually shaped supernova remnant observed in the Small Magellanic Cloud is likely the remains of an exploded white dwarf.

The new image, taken by NASA’s Chandra X-ray Observatory, shows SNR 0104-72.3 (SNR 0104 for short), in the Milky Way’s neighbouring galaxy the Small Magellanic Cloud. Astronomers think that SNR 0104 is the remains of a so-called Type Ia supernova caused by the thermonuclear explosion of a white dwarf.

In this composite made of X-rays from Chandra shown in purple and infrared data from Spitzer shown in green and red, SNR 0104 looks unlike other likely Type Ia remnants found in our own Galaxy. Image: X-ray (NASA/CXC/Penn State/S.Park & J.Lee); IR (NASA/JPL-Caltech).

White dwarfs are the final evolutionary state of most stars, the dense core left behind after a red giant has shed its outer layers. One possible explanation of the curious structure is that the explosion of the white dwarf itself was strongly asymmetrical and produced two bright lobes of emission, seen to the upper right and lower left in the image. The large amount of iron in these lobes indicates that SNR 0104 was likely formed by a Type Ia supernova.

The explosion may also have been influenced by a complicated surrounding environment. The green shells on the left and right side of the remnant correspond to local material that has been swept up by the explosion. Therefore, the lack of material to the north and south of the star may have biased the direction in which the stellar debris expanded.

The explosion mechanism, and the possible effect of the environment will provide the focus for future study by astronomers working on the supernova.

SNR 0104 may also provide key information about the little studied class of so-called “prompt” Type Ia supernovas caused by the demise of younger, more massive stars than average. Astronomers speculate that SNR 0104 might be located within a star-forming region, and note the presence of a nearby massive star. Again, more data will be needed to test this hypothesis.

The new image was released during the 214th meeting of the American Astronomical Society held in Pasadena, California, this week.