The Orion–Eridanus Superbubble or Eridanus Soft X-ray Enhancement is a

superbubble A superbubble or supershell is a cavity which is hundreds of light years across and is populated with hot (106 K) gas atoms, less dense than the surrounding interstellar medium, blown against that medium and carved out by multiple supern ...

located west of the

Orion Nebula The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the constellation of Orion. It is one of the brightest nebulae and is visible to the naked eye in the nig ...

. The region is formed from overlapping

supernova remnant A supernova remnant (SNR) 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 mat ...

s that may be associated with the

Orion OB1 Orion OB1 (Ori OB1) is a contingent group of several dozen hot giant stars of spectral types O and B in Orion. Associated are thousands of lower-mass stars, and a (smaller but significant) number of protostars. It is part of the larger Orion mo ...

stellar association; the bubble is approximately 1200 ly across. It is the nearest superbubble to the

Local Bubble The Local Bubble, or Local Cavity, is a relative cavity in the interstellar medium (ISM) of the Orion Arm in the Milky Way. It contains the closest of celestial neighbours and among others, the Local Interstellar Cloud (which contains the Sola ...

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 Carl Eugene Heiles (born 1939) is an American astrophysicist noted for his contribution to the understanding of diffuse interstellar matter through observational radio astronomy. Biography Heiles was born in Toledo, Ohio. He did his undergradua ...

and interstellar optical emission line observations by Reynolds and Ogden in the 1970s.

References

Orion molecular cloud complex Supernovae Superbubbles {{nebula-stub

See also

References