Supernovae are intensely bright
objects. They are formed when a star reaches the end of its life with a
dramatic explosion, expelling most of its material out into space. The subject
of this new Hubble image, spiral galaxy NGC 6984, played host to one of these
explosions back in 2012, known as SN 2012im. Now, another star has exploded,
forming supernova SN 2013ek — visible in this image as the prominent, star-like
bright object just slightly above and to the right of the galaxy's center.
SN 2012im is known as a Type Ic
supernova, while the more recent SN 2013ek is a Type Ib. Both of these types
are caused by the core collapse of massive stars that have shed — or lost —
their outer layers of hydrogen. Type Ic supernovae are thought to have lost
more of their outer envelope than Type Ib, including a layer of helium.
The observations that make up this new
image were taken on August 19, 2013, and
aimed to pinpoint the location of this new explosion more precisely. It is so
close to where SN 2012im was spotted that the two events are thought to be
linked; the chance of two completely independent supernovae so close together
and of the same class exploding within one year of one another is a very
unlikely event. It was initially suggested that SN 2013ek may in fact be SN
2012im flaring up again, but further observations support the idea that they
are separate supernovae — although they may be closely related in some
as-yet-unknown way
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