Credit: ESO/M. McCaughrean
A pair of jets protrude outwards in near-perfect symmetry in this image of Herbig-Haro object (HH) 212, taken by ESO’s already decommissioned Infrared Spectrometer And Array Camera (ISAAC).
The object lies in the constellation of Orion (The Hunter) in a dense molecular star-forming region, not far from the famous Horsehead Nebula.
In regions like this, clouds of dust and gas collapse under the force
of gravity, spinning faster and faster and becoming hotter and hotter
until a young star ignites at the cloud’s centre. Any leftover material
swirling around the newborn protostar comes together to form an accretion disc
that will, under the right circumstances, eventually evolve to form the
base material for the creation of planets, asteroids and comets.
Although
this process is still not fully understood, it is common that a
protostar and its accretion disc, as seen here edge-on, are the cause of
the jets in this image. The star at the centre of HH 212 is indeed a
very young star, at only a few thousand years old. Its jets are
remarkably symmetric, with several knots appearing at relatively stable
intervals. This stability suggests that the jet pulses vary quite
regularly, and over a short timescale — maybe even as short as 30 years!
Further out from the centre, large bow shocks spread out into
interstellar space, caused by ejected gas colliding with dust and gas at
speeds of several hundred kilometres per second.
