Gamma Ray Burst (GRB)

Why in News?

•  A rare astronomical event involving a compact binary merger emitting long Gamma Ray Burst (GRB) twinned with a kilonova emissions was recently reported. 

Highlights 

• This never before scientifically accepted or proven combination was also confirmed by India’s largest optical telescope, Devasthal Optical Telescope (DOT).
• The GRB lasted for over 50 seconds and identified as GRB211211A.
• Kilonovae occur when two compact objects, like binary neutron stars or a neutron star and a black hole, collide
• GRBs are massive but extremely bright, high-energy short gamma radiations which get released when massive stars collapse or die in the Universe.
• They are the most powerful events in the universe, detectable across billions of light-years.
• A light-year is the distance a beam of light travels in a single Earth year, or 9.5 trillion kilometers.
• Astronomers classify them as long or short based on whether the event lasts for more or less than two seconds
• They observe long bursts in association with the demise of massive stars.
• When a star much more massive than the Sun runs out of fuel, its core suddenly collapses and forms a black hole.
• Black hole refers to a point in space where matter is so compressed as to create a gravity field from which even light cannot escape.
• As matter swirls toward the black hole, some of that escapes in the form of two powerful jets that rush outward at almost the speed of light in opposite directions.
• Astronomers only detect a GRB when one of these jets happens to point almost directly toward Earth.
• Each jet drills through the star, producing a pulse of gamma rays – the highest-energy form of light – that can last up to minutes. Following the burst, the disrupted star then rapidly expands as a supernova.
• A supernova Is the name given to an exploding star that has reached the end of its life.