Source: TimesofIndia

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Context

• On a significant collaborative mission, the French-Chinese Space Variable Objects Monitor (SVOM) satellite was successfully launched by a Long March 2-C rocket from the Xichang Satellite Launch Center in southwestern China.
• This satellite aims to delve into the universe's most powerful explosions, known as gamma-ray bursts (GRBs), providing crucial data on the cosmos's history and evolution.

Details

• Orbit: The SVOM satellite will orbit at an altitude of 625 kilometers above Earth.

Mission Objectives

• The primary mission of the 930-kilogram SVOM satellite, equipped with instruments from both France and China, is to detect and study gamma-ray bursts.
• These bursts are incredibly bright cosmic events caused by massive star explosions or compact star mergers.
• They emit energy comparable to over a billion billion suns, carrying significant information about the cosmic environments they traverse.
• This data is vital for understanding galaxy formation and the transformation of gas clouds over time.
• Historical Insight: Observing gamma-ray bursts allows scientists to look back in time, as the light from these objects takes millions to billions of years to reach Earth.
• Mystery Unraveling: SVOM aims to uncover several mysteries associated with GRBs, including detecting the most distant and earliest bursts in the universe's history.

Scientific Collaboration

• This project marks a notable cooperation between the French and Chinese space agencies, highlighting international scientific collaboration despite limited space partnerships due to US restrictions on technology transfer.
• China and France previously launched the CFOSAT oceanographic satellite in 2018, and European nations have participated in China's Chang'e lunar exploration missions.

Gamma-Ray Bursts (GRBs)

• Gamma-ray bursts (GRBs) are the most powerful explosions observed in the universe, emitting enormous amounts of energy in the form of gamma rays.
• These brief yet intense events originate from catastrophic cosmic events, such as the collapse of massive stars or the mergers of neutron stars.
• Discovery: GRBs were first discovered in the late 1960s by the Vela satellites, which were initially designed to detect nuclear explosions. Instead, they detected bursts of gamma radiation from space.
• Observation: GRBs are detected by space-based observatories equipped with gamma-ray detectors. Notable missions include NASA's Swift and Fermi Gamma-ray Space Telescopes.

Types of Gamma-Ray Bursts

• Long GRBs:
  • Duration: Lasting more than 2 seconds.
  • Cause: Typically associated with the collapse of massive stars (hypernova or collapsar model).
  • Characteristics: Often found in star-forming regions and associated with supernovae.
• Short GRBs:
  • Duration: Lasting less than 2 seconds.
  • Cause: Believed to result from the mergers of compact objects, such as neutron stars or a neutron star and a black hole.
  • Characteristics: Typically found in older stellar populations and not usually associated with supernovae.

Mechanisms of Gamma-Ray Bursts

• Collapsar Model: In long GRBs, a massive star exhausts its nuclear fuel, leading to a core collapse. The resulting black hole or neutron star generates jets of material moving at near-light speed. These jets produce gamma rays as they collide with surrounding material.
• Neutron Star Merger Model: In short GRBs, the merger of neutron stars leads to the formation of a black hole. The intense gravitational forces and resulting accretion disk generate jets that emit gamma rays.

Sources:

TimesofIndia

PRACTICE QUESTION Q. Gamma-ray bursts are key phenomena in the field of high-energy astrophysics, providing insights into the most violent events in the universe. Discuss. (10 marks)