Multicoloured view of supernova remnant
Copyright: ESA/XMM-Newton & NASA/Chandra (X-ray); NASA/WISE/Spitzer (Infrared)
Copyright: ESA/XMM-Newton & NASA/Chandra (X-ray); NASA/WISE/Spitzer (Infrared)
Most celestial events unfold over thousands of years or more, making
it impossible to follow their evolution on human timescales. Supernovas
are notable exceptions, the powerful stellar explosions that make stars
as bright as an entire galaxy for several days.
Although they are
very rare – only a few such explosions take place every century in a
typical galaxy – supernovas can be seen with the naked eye if they are
reasonably nearby. In fact, when supernovas were discovered they were
thought to be new stars appearing in the sky – ‘nova’ means new in
Latin.
Astronomers have recorded supernovas long before a
theoretical understanding of these events as stellar explosions was
developed in the 20th century. The most ancient documented record dates
back to 185 AD, when Chinese astronomers saw a ‘guest star’ that
remained visible for several months, in the vicinity of the two stars
Alpha and Beta Centauri.
The material ejected during these
explosions sweeps up gas and dust from the surroundings, creating
picturesque supernova remnants that can be observed long after the
explosion. Modern astronomers believe that the object shown in this
image, the supernova remnant RCW 86, is what remains of the supernova
that was discovered in 185 AD.
The blue and green glow at the
edges of the bubble represents X-ray emission from hot gas, heated to
millions of degrees by shock waves generated after the explosion. The
diffuse red glow marks infrared emission from warm dust in the
interstellar medium around RCW 86. Sprinkled across the image, in
yellow, are young stars that shine brightly at infrared wavelengths.
This
image combines X-ray data from ESA’s XMM-Newton and NASA’s Chandra
X-ray Observatory (combined to form the blue and green colours) with
infrared observations from NASA’s Spitzer Space Telescope and Wide-Field
Infrared Survey Explorer (yellow and red).
The supernova remnant RCW 86 is some 8000 light-years away.
This image was first published in 2011.
Source: ESA - Space Images
