* Eddington Limit: This limit describes the maximum luminosity a star can achieve while still maintaining hydrostatic equilibrium. Stars exceeding this limit would experience intense radiation pressure that would push their outer layers outwards, preventing them from collapsing further.
* Instability due to Radiation Pressure: Massive stars produce enormous amounts of energy through nuclear fusion. This radiation pressure becomes so strong in stars with masses exceeding 150 solar masses that it overcomes gravity, leading to instability and preventing the star from forming.
* High Mass Loss Rates: Massive stars have very strong stellar winds, losing mass at a high rate. This loss of mass further contributes to their instability and makes it difficult for them to sustain their massive size.
* Pair-Instability Supernova: Stars in the mass range of 130-250 solar masses are thought to undergo a specific type of supernova called a "pair-instability supernova." In these stars, the intense radiation field can create electron-positron pairs, leading to a sudden loss of pressure and a catastrophic collapse, leaving no remnant behind.
It's important to note: The exact upper limit for star formation is still under debate and research, and there might be other factors at play. However, the Eddington Limit and pair-instability supernova are the most commonly cited reasons why stars larger than 150 solar masses are unlikely to exist.
