Summary: TEHRAN (FNA)- New research suggests most of Earth's heavy metals were spewed from a largely overlooked kind of star explosion called a collapsar
when the liquid sphere becomes gravitational collapsar
In the collapsar
model , LGRBs are only formed by massive stars with Z/[Z.sub.[??]] below [equivalent] 0.1-0.3.
A respeito de sua origem, o modelo mais aceito e o de colapso de estrelas supermassivas (Collapsar
Model) em sistemas binarios (o que parece ser mais provavel) ou isoladas.
is another name for which astronomical phenomenon?
In the popular collapsar
model put forth by Woosley and Andrew MacFadyen (now at New York University), the black hole and disk both form quickly, and the wind, made mostly of the radioactive isotope nickel-56, is strong enough to blow apart the star.
But if a quasar is on its inexorable way to becoming a black hole--or "collapsar
" as Campbell put it--all the interstellar matter and star stuff surrounding this gravitational collapse would be screaming in cosmic agony throughout the electromagnetic spectrum while being sucked into this ineffable vortex.
Because the condition [g.sub.00] = 0 is the collapse condition, the surface of the collapsar
is the mirror separating the spaces with both positive and negative flow of the observable time.
A basic assertion of the collapsar
model is that the duration of the GRB prompt phase (where [T.sub.90] is used as a proxy) is the difference of the time that the central engine operates minus the time it takes for the jet to break out of the star: [T.sub.90] ~ [t.sub.engine] - [t.sub.breakout].
In 1999 a clear winner emerged out of the hundreds of competing theories attempting to explain GRBs: the "collapsar
" model developed by Stan Woosley (University of California, Santa Cruz) and his graduate student Andrew MacFadyen (now at the institute for Advanced Study).
According to one theory, known as the collapsar
model, gravity rapidly crushes the core of a star at least 20 times as massive as the sun down to a black hole--a superlatively dense cinder whose gravity is so strong not even light can escape its grasp.
Our geometric investigation is based on what seems to be the only time-dependent study of a collapsar
, namely that of Oppenheimer and Snyder  (OS).