Short
Definition
A supernova remnant is a construction formed by the
expanding debris left behind after a massive star undergoes a supernova
explosion. It consists of a complex structure of shockwaves, gas, and dust,
formed from the ejected material of the exploded star.
Detailed Definition
A supernova remnant undergoes a sequence of five distinct stages before
reaching its final form.
First,
the ejecta expands freely, gradually shedding their mass into the circumstellar
or interstellar medium. Subsequently, the remnant begins to gather and compress
surrounding gas, forming a prominent shell. In the ensuing phase, the shell
undergoes cooling, resulting in the formation of a thinner, more delicate outer
layer enveloping the still-hot interior. As the interior continues to cool, the
shell expands further under its own momentum. Finally, the remnant merges with
the surrounding interstellar medium, culminating in the formation of a
fully-fledged supernova remnant.
Notable
examples of supernova remnants include the Crab Nebula, the remnants of SN
1572, and Kepler, the remnants of SN 1604, named after Johannes Kepler.
G1.9+0.3, discovered in the galactic centre, stands as the most recent known
remnant within our galaxy.
Etymology
The word "supernova" originates from Latin, where "super"
means "above" or "beyond," and "nova" translates
to "new." The word "remnant"
comes from the Latin term "remanens," which means
"remaining" or "leftover."
