The supernova remnant Simeis 147

This structure, also referred to in catalogs as Sh2-240, covers an area of ​​nearly 3 degrees on the sky (the equivalent of 6 full moons). The mentioned field corresponds to an actual diameter of about 150 light-years, since the debris cloud is at an estimated distance of 3000 years-light. The bright star that dominates the right side of the image is El Nath (Beta Tauri), located toward the boundary between the constellations of Bull (Taurus in Latin) and the Charioteer (Auriga in Latin), on a point of land almost exactly sky opposite to the galactic center.

This remarkable composition comprises image data obtained with narrow-band filters to highlight emission from hydrogen atoms. This allows to follow the convolutions of gas that glows (pictured at right) to be hit by the shock wave from the supernova.

The supernova remnant  has an estimated age of 40,000 years, which means that the light from the massive stellar explosion that gave birth first came to Earth 40,000 years ago. But this expanding remnant is not the only result of this cosmic catastrophe. Behind him also left a pulsar, that is, a neutron star with a very rapid rotation, all that remains of the original star's core.

That reconstructs the supernova explosion that gave birth to the Crab Nebula Crab Nebula-or is the object identified as M1 after clicking Mark the Deep Sky Objects - observed in 1054 in our era:

Supernovae and supernova remnants

Approximately every 50 years a massive star in our galaxy blows up in a supernova explosion (see videos and animations). Supernovae are one of the most violent events in the universe and the force of the explosion generates a blinding flash of radiation and shock waves similar to an explosion.

It was initially classified supernovae according to their optical properties. Type II supernovae show clear evidence of hydrogen in the expanding debris ejected in the explosion, which is not true of Type Ia supernovae. Recent research allowed refine these types and therefore proposed a classification that takes into account the types of stars that give rise to supernovae. An explosion of Type II and Type Ib and the Type Ic, are produced by the catastrophic collapse of the core of a massive star. A Type Ia supernova occurs by a sudden thermonuclear explosion that disintegrates a star white dwarf.

Type II supernovae occur in regions with many bright young stars, such as the spiral arms of galaxies. Apparently not occur in elliptical galaxies, whose dominant population consists of old stars of low mass. Since stars are typically bright young stars with a mass 10 times larger than the Sun, this tests, among others, to conclude that massive stars produce supernovae of Type II.

Some supernovae of Type I share many characteristics with Type II supernovae. Such supernovae, classified as Type Ib and Ic type, apparently differ from Type II because they have lost their hydrogen outer casing before the explosion. The hydrogen envelope could have been lost due to strong field emission prior to the explosion or it was ripped off by a companion star.