Exploded Star Blooms Like a Cosmic Flower
By NASA.gov // February 16, 2015
NASA’s Chandra X-ray captures stunning image
NASA.gov – Because the debris fields of exploded stars, known as supernova remnants, are very hot, energetic, and glow brightly in X-ray light, NASA’s Chandra X-ray Observatory has proven to be a valuable tool in studying them.
G299 was left over by a particular class of supernovas called Type Ia. Astronomers think that a Type Ia supernova is a thermonuclear explosion – involving the fusion of elements and release of vast amounts of energy − of a white dwarf star in a tight orbit with a companion star.
If the white dwarf’s partner is a typical, Sun-like star, the white dwarf can become unstable and explode as it draws material from its companion. Alternatively, the white dwarf is in orbit with another white dwarf, the two may merge and can trigger an explosion.
Regardless of their triggering mechanism, Type Ia supernovas have long been known to be uniform in their extreme brightness, usually outshining the entire galaxy where they are found.
This is important because scientists use these objects as cosmic mileposts, allowing them to accurately measure the distances of galaxies billions of light years away, and to determine the rate of expansion of the Universe.
Traditional theoretical models of Type Ia supernovas generally predict that these explosions would be symmetric, creating a near perfect sphere as they expand.
These models have been supported by results showing that remnants of Type Ia supernovas are more symmetric than remnants of supernovas involving the collapse of massive stars.
However, astronomers are discovering that some Type Ia supernova explosions may not be as symmetric as previously thought.
G299 could be an example of such an “unusual” Type Ia supernova. Using a long observation from Chandra, researchers discovered the shell of debris from the exploded star is expanding differently in various directions.
In this new Chandra image, red, green, and blue represent low, medium, and high-energy X-rays, respectively, detected by the telescope.
The medium energy X-rays include emission from iron and the hard-energy X-rays include emission from silicon and sulfur. The X-ray data have been combined with infrared data from ground-based 2MASS survey that shows the stars in the field of view.