HELIUM FLASH Meaning and
Definition
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Helium flash refers to a phenomenon that occurs in the core of low-mass stars during their evolution. Specifically, when a star exhausts its hydrogen fuel in its core, it enters a phase known as the red giant phase. During this phase, the star's core contracts and heats up, causing rapid fusion reactions involving helium atoms to occur.
The helium flash occurs when the temperature at the core of the star reaches a critical point, around 100 million degrees Celsius. At this temperature, the helium nuclei combine and fuse together, forming carbon atoms. This nuclear fusion process releases an enormous amount of energy, causing a sudden increase in the star's energy production.
However, unlike the initial fusion of hydrogen in the star's core, which resulted in a stable fusion process, the helium flash is a brief and explosive event. It lasts only a few minutes but can release as much energy as the Sun would in 10 billion years. This energy release causes the star's outer layers to expand rapidly, and it is during this phase that the star becomes a red giant.
The helium flash is a crucial event in stellar evolution as it marks the beginning of a star's transition from the red giant phase to becoming a white dwarf. After the helium flash, the star begins to shed its outer layers into space, forming a planetary nebula, while the core, primarily composed of carbon and oxygen, continues to evolve and eventually becomes a stable, extremely dense white dwarf.
Etymology of HELIUM FLASH
The word "helium flash" consists of two components: "helium" and "flash".
The term "helium" derives from the Greek word "helios", meaning "sun". Initially, helium (symbol: He) was discovered in the sun's spectrum before it was detected on Earth. Therefore, it was given this name since it was associated with the sun.
The word "flash" originated from the Old English word "flæsc", which means "a sudden burst of light or flame". Over time, the meaning of "flash" evolved to include other rapid or instantaneous events.
Thus, the term "helium flash" is a combination of "helium", referring to the element, and "flash", signifying a sudden and energetic event, referencing a particular astrophysical phenomenon.
