Why were rocky planetesimals able to form closer to the young Sun?

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asteroid Ida and its satellite, Dactyl — Small body Asteroid Ida and its satellite, Dactyl, photographed by the Galileo spacecraft on August 28, 1993, from a distance of about 10,870 km (6,750 miles). Ida is about 56 km (35 miles) long and shows the irregular shape and impact craters characteristic of many asteroids. The Galileo image revealed that Ida is accompanied by a tiny companion about 1.5 km (1 mile) wide, the first proof that some asteroids have natural satellites.

Rocky planetesimals were able to form closer to the young Sun because the temperatures in the inner solar nebula were too high for volatile substances—such as water, carbon dioxide, and ammonia—to condense into ices.123

While these volatile compounds remained in a gaseous state near the Sun, materials with higher freezing temperatures, such as metal-containing silicates, were able to solidify. Consequently, the solid material available for accretion in the inner solar system was primarily composed of these rocky, less-volatile substances. This resulted in the formation of small, dense, rocky bodies, whereas the cooler regions beyond the snow line allowed for the condensation of abundant ices, leading to the development of massive, gas-rich outer planets.12