Orion–Eridanus Superbubble
Encyclopedia
The Orion–Eridanus Superbubble, or Eridanus Soft X-ray Enhancement is a superbubble
in the Orion Nebula
. The region is formed from overlapping supernova remnant
s that may be be associated with the Orion OB1
stellar association; the bubble is approximately 1200 ly across. It is the nearest superbubble to the Local Bubble
containing the sun, with the respective shock fronts being about 500 ly apart.
The structure was discovered from 21 cm radio observations
by Carl Heiles in the 1970s.
Superbubble
Superbubble is the astronomical term used to describe a cavity hundreds of light years across filled with 106 K gas blown into the interstellar medium by multiple supernovae and stellar winds...
in the Orion Nebula
Orion Nebula
The Orion Nebula is a diffuse nebula situated south of Orion's Belt. It is one of the brightest nebulae, and is visible to the naked eye in the night sky. M42 is located at a distance of and is the closest region of massive star formation to Earth. The M42 nebula is estimated to be 24 light...
. The region is formed from overlapping supernova remnant
Supernova remnant
A supernova remnant is the structure resulting from the explosion of a star in a supernova. The supernova remnant is bounded by an expanding shock wave, and consists of ejected material expanding from the explosion, and the interstellar material it sweeps up and shocks along the way.There are two...
s that may be be associated with the Orion OB1
Orion OB1 Association
The Orion OB1 stellar association is a contingent group of several dozen hot giant stars of spectral types O and B. Associated are thousands of lower-mass stars, and a number of protostars. It is part of the larger Orion Molecular Cloud Complex...
stellar association; the bubble is approximately 1200 ly across. It is the nearest superbubble to the Local Bubble
Local Bubble
The Local Bubble is a cavity in the interstellar medium of the Orion Arm of the Milky Way. It is at least 300 light years across and has a neutral hydrogen density of about 0.05 atoms per cubic centimetre, or approximately one tenth of the average for the ISM in the Milky Way , and half that for...
containing the sun, with the respective shock fronts being about 500 ly apart.
The structure was discovered from 21 cm radio observations
Radio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...
by Carl Heiles in the 1970s.