A new study of supernova remnants allowed scientists to categorize the
explosion that created them based on their shape
Supernovas that come from thermonuclear explosion on white dwarfs (known as
Type Ia) produce very symmetric remnants
Another type, created when a very massive star collapses, results in more
asymmetrically shaped remnants
These two supernova remnants
are part of a new study from NASA's Chandra X-ray Observatory that shows how the
shape of the remnant is connected to the way the progenitor star exploded.
In this study, a team of researchers examined the shapes of 17 supernova
remnants in both the Milky Way galaxy and a neighbor galaxy, the Large
Magellanic Cloud.
The results revealed that one category of supernova explosion, known as
"Type Ia," generated a very symmetric, circular remnant. This type of
supernova is thought to be caused by a
thermonuclear explosion of a white dwarf, and is often used by astronomers as a
"standard candle" for measuring cosmic distances. The image in the right
panel, the so-called Kepler supernova remnant, represents this type of
supernova.
On the other hand, remnants tied to the "core collapse"
family of supernova explosions were distinctly more asymmetric, which is
seen in the morphology of the G292.0+1.8 remnant (left). The research team
measured asymmetry in two ways: how spherical or elliptical the supernova
remnant was
and how much one side of
the remnant mirrors its opposite side. In G292, the asymmetry is subtle but can
be seen in elongated features defined by the brightest emission (colored
white).
Out of the 17 supernova remnants sampled, ten were independently classified
as the core-collapse variety, while the remaining seven of them were classified
as Type Ia. One of these, a remnant known as SNR 0548-70.4, was a bit of an
"oddball". This one was considered a Type Ia based on its chemical abundances,
but has the asymmetry of a core-collapse remnant.
Fast Facts for
G292.0+1.8: Credit NASA/CXC/UCSC/L. Lopez et al. Scale 11.5
arcmin across. Category Supernovas & Supernova Remnants
Coordinates (J2000) RA 11h 24m 36.00s | Dec -59° 16'
00.00" Constellation Centaurus Observation Dates 6
observations between September - October 2006 Observation Time 144
hours Obs. IDs 6677-6680, 8221, and 8447 Color Code Energy:
Red (low energy); Orange (medium-low energy); Green (medium energy); Blue (high
energy) Instrument ACIS References Lopez, L. et al, 2009 706
L106-L109; Park, S. et al, 2007, ApJ, 670 L121-L124 Distance Estimate
20,000 light years Release Date December 17, 2009
Fast Facts for Kepler's Supernova Remnant: Credit NASA/CXC/UCSC/L.
Lopez et al. Scale 5 arcmin across. Category Supernovas &
Supernova Remnants Coordinates (J2000) RA 17h 30m 40.80s | Dec -21°
29' 11.00" Constellation Ophiuchus Observation Dates 6
observations between April - August 2006 Observation Time 208
hours Obs. IDs 6714-18, 7366 Color Code Energy: Red (low
energy);Yellow/Green (medium energy); Blue (high energy) Instrument
ACIS Also Known As SN 1604, G004.5+06.8, V 843
Ophiuchi References Lopez, L. et al, 2009 706 L106-L109; Park, S. et
al, 2007, ApJ, 670 L121-L124 Distance Estimate 13,000 light years
Release Date December
17, 2009
