A Heroic Star Survives A Supernova Blast

When a very heavy star, weighing-in at about eight times the mass of our Sun, runs out of fuel, it has reached the end of that long stellar road. At this unfortunate, fatal point, the doomed heavy star collapses and blasts itself to pieces in the fiery, raging fury of a supernova explosion. Supernovae are extremely violent events, and can be so brilliant that they actually outshine their entire host galaxy–at least, for a time. Recently, a team of astronomers, using NASA’s Chandra X-ray Observatory (CXO), as well as other telescopes, announced that they had spotted a true stellar hero–a companion star that had managed to survive the ferocious explosion of its sister-star that had gone brilliantly, fatally supernova!

The supernova remnant is dubbed DEM L241, and it is a denizen of the Large Magellanic Cloud (LMC), which is a small satellite galaxy of our own large, barred, star-blazing spiral, the Milky Way. The system contains either a neutron star or black hole dancing around with the heroic stellar survivor star–which is a massive star, in its own right. CXO‘s X-ray vision uncovered a point-like source inhabiting the debris field created when the doomed, massive star blasted itself to bits in a fiery supernova tantrum.

The heroic surviving star, inhabiting the stellar explosion’s supernova remnant, is situated in an HII region–DEM L241. An HII region (pronounced “H-two”) forms when the radiation spewing out from active, searing-hot, fiery young stars strips away the electrons from neutral hydrogen atoms (HI), thus creating clouds of ionized hydrogen (HII). This HII region is located within the LMC.

In general, when a massive star goes supernova, the violence of the event also disintegrates any companion star that is unlucky enough to be part of the doomed system. This is usually the result of the close proximity between the two unfortunate sister-stars. However, for some reason, this did not occur in the system CXO recently observed. The companion star is still “alive” and kicking, located right at the heart of the debris field that the supernova left in its wake. 바카라사이트

A new image, released in March 2014, is based on an earlier snapshot of the object, collected during the Magellanic Cloud Emission Line Survey (MCELS), to which astronomers have contributed data derived from CXO. The newer observations reveal the contours of the supernova remnant that the exploding, doomed star left behind to tell its tragic story.

Because of the extreme temperatures that still roast the entire area, the material within the supernova remnant is millions of degrees, and it shoots out X-rays as a result of this intense heat.

Dr. R. Davies, Dr. K. Elliott, and Dr. J. Meaburn, whose last initials were combined to give the object the first half of its name, initially mapped DEM L241 back in 1976. One of the most fascinating aspects of the new observations was the discovery of an exoplanet dwelling within the supernova remnant. Earlier observations only observed the HII region as a whole, but CXO was able to observe the point-like X-ray source at its very heart. Astronomers believe that the surviving companion star is much larger and more massive than our Sun.

A Stellar Tantrum

Stars of all masses live out the best years of their stellar lives on what is termed the main-sequence. The main-sequence is that brilliant time in a star’s “life” when it maintains a precious, delicate balance between two warring forces–radiation pressure and gravity. The radiation pressure of a star pushes everything away from the star, and it keeps this enormous roiling sphere of seething-hot gas bouncy against the horrendous crush of its own gravity, that pulls everything in. This radiation pressure is derived from the process of nuclear fusion which is occurring in the hot heart of the star. Nuclear fusion, within the star, begins with the burning of hydrogen–the most abundant, as well as the lightest, atomic element in the Universe. The star fuses its supply of hydrogen into helium, which is the second-lightest atomic element in the Universe. This process, termed stellar nucleosynthesis, continually fuses heavier atomic elements from lighter ones. All of the atomic elements heavier than helium (metals, to astronomers), were churned out in the nuclear-fusing cores of our Universe’s billions upon billions of stars–or else in their final blast of glory, when they went supernova.

When a very massive main-sequence star has finally fused its entire necessary supply of precious hydrogen fuel, it is the end. The very heavy star, at this tragic point, is not able to hold its own against the terrific crushing force of its own hefty weight, and gravity wins the final battle–marking the end of the war. Gravity has prevailed against its great foe–radiation pressure–because the erstwhile star has run out of nuclear fuel to burn.

A supernova blows the tragedy that was once a star to shreds, blasting its multicolored shimmering rainbow of gaseous layers out into the space between stars. This violent explosion occurs when the iron core of the heavy star manages to gain the hefty weight of 1.4 solar-masses, thus triggering the detonation of the unfortunate star. The most massive stars dwelling in the Cosmos collapse and blast themselves into the oblivion of a stellar-mass black hole. Massive stars–that are not quite as massive–also blow themselves up, but they leave behind the sad leftovers of what they once were in the form of a weird stellar-corpse called a neutron star. Neutron stars are extremely dense objects that are about the size of Chicago–but a teaspoon full of neutron star material weighs as much as a herd of elephants.


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