Context: Researchers have reported that the universe may have another way to produce the element gold, apart from collision of neutron stars. They have reported the first direct observational evidence of a process called r-process nucleosynthesis in a powerful flare emitted by a magnetar in 2004.
Relevance of the Topic: Prelims: Key facts about Neutron stars; Magnetars; r-process nucleosynthesis.
Known Source of Gold- Neutron Star Collisions:
- Neutron Stars: Incredibly dense remnants of supermassive stars (with masses around 1025 times the mass of the Sun) that have exploded as supernovae.
- Gold is predominantly produced in the violent collisions and mergers of ultra-dense neutron stars. Such events are detected using space telescopes and gravitational wave detectors (E.g., LIGO).
The New Discovery- Magnetar Flares produce Gold
- Magnetars: Types of neutron stars with much more powerful magnetic fields than normal neutron stars. Most powerful known magnetic objects in the universe with magnetic fields in the range of 1015 gauss.
- Magnetar Flares: Magnetar occasionally release large bursts of energy in flares (much powerful than solar flares).
- Observation:
- A powerful flare emitted by a magnetar in 2004 was recorded by NASA's Compton Gamma Ray Observatory.
- Almost a day after the flare, a delayed burst of high-energy gamma rays was released.
- The delayed emission was inconsistent with standard flare afterglows and contained evidence of radioactive decay from r-process nucleosynthesis.
- r-process nucleosynthesis: The rapid neutron capture process is the major nucleosynthesis process responsible for the synthesis of heavy nuclei, including gold.
- The study concludes that some magnetar flares can eject neutron-rich matter into space, where it goes through r-process nucleosynthesis to create heavy elements like gold.
Significance
- The early universe only had hydrogen, helium, and trace amounts of lithium. All other elements were created later in stars, cosmic explosions, and laboratory experiments. Mapping the sources tells us how galaxies, stars, and planets took shape over time.
- Understanding the sources can also reveal how often an element was produced, and how the presence of an element influenced the source’s own evolution.
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