Credit: ESO / Manu Mejias
The Crab Nebula,
which also goes by the names Messier 1, NGC 1952 and Taurus A, is one
of the best studied astronomical objects in the sky. It is the remnant
of a supernova explosion which was observed by Chinese astronomers in
1054. The tangled filaments visible in this image are the remains of the
exploded star, which are still expanding outwards at about 1500
kilometres per second.
Although not visible to the naked
eye due to foreground filaments of helium and hydrogen the heart of the
nebula hosts two faint stars. It is one of these that is responsible
for the nebula that we see today — a star that is known as the Crab Pulsar,
or CM Tau. This is the small, dense, corpse of the original star that
caused the supernova. It is now only about 20 kilometres in diameter and
rotates around its axis 30 times every second!
The star emits pulses of radiation in all wavelengths, ranging from gamma rays — for which it is one of the brightest sources in the sky — to radio waves.
The radiation from the star is so strong that it is creating a wave of
material that is deforming the inner parts of the nebula. The appearance
of these structures changes so fast that astronomers can actually
observe how they reshape. This provides a rare opportunity as cosmic
timescales are usually much too long for change to be observed to this
extent.
The data from the Wide Field Imager
on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in
Chile used to make this image were selected from the ESO archive by Manu Mejias as part of the Hidden Treasures competition.
Source: ESO/Images
