Which statement comparing halo stars to our Sun is not true?

The statement that halo stars have a higher average metallicity than the Sun is indeed not true. Halo stars are typically older and formed in the early universe, where the abundance of heavier elements (metals) was lower due to insufficient time for the processes that create metals through nuclear fusion and supernova explosions. Consequently, halo stars tend to have a lower metallicity compared to younger stars like our Sun, which formed in a richer chemical environment that had been enriched by earlier generations of stars. This distinctive aspect of halo stars is critical in understanding the formation and evolution of the Milky Way galaxy, as they often represent the ancient population of stars that provide insights into the early conditions of the universe.