The answer is, "The core of a star must reach a temperature of 10,000,000 degrees Celsius for hydrogen fusion to begin."
Answer:
10,000,000 °C
Explanation:
The fusion of Hydrogen can happen only in certain conditions. The temperatures should be above 100,000,000°C. But inside the core of the stars this limit comes down to just 10,000,000°C or 10 million °C. This difference in temperature is caused caused by the extreme pressure being applied in the core due to gravity of the Sun.
So the fusion will start as the core achieves a temperature of 10 million °C. If a star achieves to attain this temperature fusion will never start and it will never be a main sequence star.
