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kilonova

A kilonova, also known as a macronova, is a luminous transient event that arises from the radioactive decay of heavy elements produced by rapid neutron capture (r-process) during the merger of compact objects such as neutron star–neutron star or black hole–neutron star systems.

In these mergers, a portion of neutron-rich matter is ejected at substantial fractions of the speed of

Kilonovae fade over days to weeks. Their light curves and colors depend on the composition of the

The concept was proposed in the late 1990s and gained observational confirmation with the detection of GW170817

Kilonovae are key targets for electromagnetic counterparts to gravitational-wave events. Ongoing surveys and follow-up programs aim

light.
The
freshly
created
heavy
nuclei
decay
and
release
energy
that
powers
electromagnetic
emission,
peaking
on
timescales
of
days
and
predominantly
in
the
optical
and
near-infrared
part
of
the
spectrum.
ejecta,
especially
the
fraction
of
lanthanides,
which
increases
opacity
and
shifts
emission
toward
longer
wavelengths.
Typical
ejecta
masses
are
on
the
order
of
0.01
to
0.1
solar
masses,
with
velocities
around
0.1
to
0.3
times
the
speed
of
light.
in
2017,
whose
gravitational-wave
signal
was
accompanied
by
a
kilonova
in
NGC
4993
and
a
short
gamma-ray
burst.
This
event
established
neutron
star
mergers
as
a
major
site
of
r-process
nucleosynthesis
and
a
cornerstone
of
multi-messenger
astronomy.
to
identify
kilonovae
independently
of
gamma-ray
bursts,
improving
estimates
of
their
rates
and
helping
constrain
the
physics
of
compact
mergers
and
the
neutron-star
equation
of
state.