Hubble solves cosmic murder mystery, and finds out which star was the 'trigger' for supernova in next-door galaxy



Nasa's Hubble space telescope solved a long-standing space mystery - what star caused a supernova in a galaxy near Earth, which would have been visible on our planet 400 years ago. The remnants - a huge, expanding cloud of gas, moving at a million miles per hour - are visible today.



There are actually two culprits - twin white dwarf stars that spiralled together until they collided.



'The logic here is the same as the famous quote from Sherlock Holmes: 'When you have eliminated the impossible, whatever remains, however improbable, must be the truth,'' said lead investigator Bradley Schaefer of Louisiana State University.



Supernova remnant 0509-67.5, located in the Large Magellanic Cloud (LMC), a small galaxy about 170,000 light-years from Earth: The bubble-shaped shroud of gas is 23 light-years across and is expanding at more than 11 million miles per hour

'The logic here is the same as the quote from Sherlock Holmes: 'When you have eliminated the impossible, whatever remains, however improbable, must be the truth,'' said lead investigator Bradley Schaefer of Louisiana State Universit

Using NASA’s Hubble Space Telescope, astronomers have solved a longstanding mystery on the type of star, or so-called progenitor, which caused a supernova seen in a nearby galaxy.



The finding yields new observational data for pinpointing one of several scenarios that trigger such outbursts.

Based on previous observations from ground-based telescopes, astronomers knew that a kind of supernova called a Type Ia supernova created a remnant named SNR 0509-67.5, which lies 170,000 light-years away in the Large Magellanic Cloud galaxy.

The type of system that leads to this kind of supernova explosion has long been a high importance problem with various proposed solutions but no decisive answer.



All these solutions involve a white dwarf star that somehow increases in mass to the highest limit.

Astronomers failed to find any companion star near the center of the remnant, and this rules out all but one solution, so the only remaining possibility is that this one Type Ia supernova came from a pair of white dwarfs in close orbit.

‘We know that Hubble has the sensitivity necessary to detect the faintest white dwarf remnants that could have caused such explosions, said lead investigator Bradley Schaefer of Louisiana State University .

The cause of SNR 0509-67.5 can be explained best by two tightly orbiting white dwarf stars spiraling closer and closer until they collided and exploded.

For four decades, the search for Type Ia supernovae progenitors has been a key question in astrophysics. The problem has taken on special importance over the last decade with Type Ia supernovae being the premier tools for measuring the accelerating universe.

Type Ia supernovae are tremendous explosions of energy in which the light produced is often brighter than a whole galaxy of stars. The problem has been to identify the type of star system that pushes the white dwarf’s mass over the edge and triggers this type of explosion.

Many possibilities have been suggested, but most require that a companion star near the exploding white dwarf be left behind after the explosion.