The third possible type of star death occurs when two such stellar remnants form a binary system and eventually collide.<\/p>\n
However, the new study has found that there is potentially a fourth type of star death.<\/p>\n
\u201cOur results show that stars can meet their demise in some of the densest regions of the Universe, where they can be driven to collide,\u201d said lead author Andrew Levan, an astronomer with Radboud University.<\/p>\n
\u201cThis is exciting for understanding how stars die and for answering other questions, such as what unexpected sources might create gravitational waves that we could detect on Earth.\u201d<\/p><\/blockquote>\n
Ancient galaxies well past their star-forming prime have few remaining massive stars.<\/p>\n
However, their cores teem with stars and a menagerie of ultra-dense stellar remnants, such as white dwarfs, neutron stars, and black holes.<\/p>\n
It has long been suspected that in this area of great activity, it would only be a matter of time before two stellar objects collided to produce a gamma-ray burst.<\/p>\n
However, evidence suggesting a merger of this type has remained elusive.<\/p>\n
Detecting a gamma-ray burst in an ancient galaxy<\/h3>\n On 19 October 2019, astronomers glimpsed hints of such a merger when NASA\u2019s Neil Gehrels Swift Observatory detected a bright flash of gamma rays that lasted a little over one minute.<\/p>\n
A gamma-ray burst lasting longer than two seconds is considered long. These bursts come from a star\u2019s death that is at least ten times the mass of the Sun.<\/p>\n
The team then used the Gemini South telescope in Chile to make long term observations of the gamma-ray burst\u2019s afterglow.<\/p>\n
The observations allowed the team to pinpoint the location of the gamma-ray burst to a region less than 100 light-years from the nucleus of an ancient galaxy, near the galaxy\u2019s supermassive black hole.<\/p>\n
The researchers also found no evidence of a supernova that would leave its imprint on the light captured by Gemini South.<\/p>\n
\u201cThe lack of a supernova accompanying the long GRB 191019A tells us that this burst is not a typical massive star death,\u201d said Rastinejad, who performed calculations to ensure a supernova was not hiding within the data.<\/p>\n
“The location of GRB 191019A, embedded in the nucleus of the host galaxy, teases a predicted but not yet evidenced theory for how gravitational-wave emitting sources might form.”<\/p>\n
The event confounds every expectation about the environments of gamma-ray bursts<\/h3>\n In typical galactic environments, the production of long gamma-ray bursts from colliding star remnants is incredibly rare.<\/p>\n
The cores of ancient galaxies, however, are anything but typical. And there may be a million of more stars crammed into a region just a few light-years across.<\/p>\n
Such extreme population density may be great enough to cause occasional stellar collisions and the death of a star. This is especially true under the gravitational influence of a supermassive black hole that would perturb the motions of stars, sending them in random directions.<\/p>\n
The stars would eventually merge, the death triggering a gigantic explosion that could be observed from vast cosmic distances.<\/p>\n\u00a9 shutterstock\/Catmando<\/figcaption><\/figure>\n“This event confounds almost every expectation we have for the environments of short and long GRBs,\u201d said Nugent, who performed crucial modelling of the host galaxy.<\/p>\n
\u201cWhile long GRBs are never found in galaxies as old and dead as GRB 191019A’s host, short GRBs, with their merger origins, have not been observed to be so connected to their hosts’ nuclei. The discovery of this event in the core of its old, quiescent galaxy opens the door to promising new avenues for the formation of binary systems that have rarely been observed before.”<\/p>\n
This type of star death may occur in other parts of the Universe<\/h3>\n The researchers believe that it is possible that this type of star death may have occurred in other crowded regions of the Universe but has gone unnoticed until now.<\/p>\n
A possible reason for this is because galactic centres are comprising of dust and gas. These could obscure the initial flash of the gamma-ray burst and the resulting afterglow.<\/p>\n
GRB 191019A may be a rare exception, allowing astronomers to detect the burst and study its aftereffects.<\/p>\n
\u201cWhile this event is the first of its kind to be discovered, it\u2019s possible there are more out there that are hidden by the large amounts of dust close to their galaxies,\u201d Fong said.<\/p>\n
\u201cIndeed, if this long-duration event came from merging compact objects, it contributes to the growing population of GRBs that defies our traditional classifications.\u201d<\/p>\n
By working to discover more of this type of star death, the researchers hope to match a GRB detection with a corresponding gravitational-wave detection.<\/p>\n
This would reveal more about their true nature, even in the murkiest of environments.<\/p>\n","protected":false},"excerpt":{"rendered":"
Learn how astrophysicists have traced a gamma-ray burst to the nucleus of an ancient galaxy, revealing a new possible type of star death.<\/p>\n","protected":false},"author":18,"featured_media":34131,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[771],"tags":[3477],"acf":[],"yoast_head":"\n
Gamma-ray burst study reveals a new possible type of star death<\/title>\n \n \n \n \n \n \n \n \n \n \n \n \n \n\t \n\t \n\t \n \n \n \n \n \n\t \n\t \n\t \n