Reminiscent of a U.S. July 4 Independence Day celebration, here is a Hubble Space Telescope image of a cosmic explosion that is quite similar to fireworks on Earth. In the nearby galaxy, the Small Magellanic
Cloud, a massive star has exploded as a supernova,
and begun to dissipate its interior into a spectacular
display of colorful filaments.
The supernova remnant (SNR), known as "E0102"
for short, is the greenish-blue shell of debris
just below the center of the Hubble image. Its name
is derived from its cataloged placement (or
coordinates) in the celestial sphere. More formally
known as 1E0102.2-7219, it is located
almost 50 light-years (15 parsecs) away from of
the edge of the massive star-forming region, N 76,
also known as Henize 1956 in the Small Magellanic
Cloud. This delicate structure glowing a multitude
of lavenders and peach hues, resides in the upper
right of the image.
The composition and thus, the coloring, of the
diffuse remnant in comparison to its star-forming
neighbor is due to the presence of very large quantities
of oxygen compared to hydrogen. E0102 is a
member of the oxygen-rich class of SNRs showing
strong oxygen and other more metal-like abundances
in its optical and X-ray spectra, and an absence
of hydrogen and helium. N 76 in contrast is made
up primarily of glowing hydrogen emission.
One explanation for the abundance of oxygen in
the SNR is that the parent star was very large and
old, and had blown away most its hydrogen as stellar
wind before it exploded. It is surmised that
the progenitor star that caused the supernova explosion
may have been a Wolf-Rayet. These stars, which
can be upward of 20 times the mass of the sun and
tens of thousands times more luminous, are famous
for having a strong stellar wind throughout their
lifetime. This stellar wind carried off material
from the outer-most shells of the star (the hydrogen
and helium shells), leaving the next most abundant
element, oxygen, as a visible signature after the
star exploded as a supernova.
Determined to be only about 2000 years old, E0102
is relatively young on astronomical scales and is
just beginning its interactions with the nearby
interstellar medium. Young supernova remnants like
E0102 allow astronomers to examine material from
the cores of massive stars directly. This in
turn gives insight on how stars form, their composition,
and the chemical enrichment of the surrounding area.
As well, young remnants are a great learning tool
to better understand the physics of supernova explosions.
E0102 was observed in 2003 with the Hubble
Advanced Camera for Surveys. Four filters that isolate
light from blue, visible, and infrared wavelengths
and hydrogen emission were combined with oxygen
emission images of the SNR taken with the Wide Field
Planetary Camera 2 in 1995.
The Small Magellanic Cloud is a nearby dwarf galaxy
to our own Milky Way. It is visible in the Southern
Hemisphere, in the direction of the constellation
Tucana, and lies roughly 210,000 light-years
(65 parsecs) distant.
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
Acknowledgment: J.C. Green (University of Colorado)