* Ice: Water ice is the dominant component, but it also contains frozen gases like carbon monoxide, carbon dioxide, methane, and ammonia.

* Dust: The dust is a mixture of silicate minerals, carbon-rich materials, and other compounds.

The exact proportions of ice and dust are uncertain, but it is believed that the nucleus of Comet Swift-Tuttle is about 50% ice and 50% dust.

Other notable components:

* Organic molecules: Comet Swift-Tuttle is known to contain complex organic molecules, including amino acids, which are the building blocks of life.

* Heavy elements: Trace amounts of heavy elements like iron, nickel, and sodium have also been detected in the comet.

Compositional significance:

The composition of Comet Swift-Tuttle is important because it provides insights into the early solar system. Comets are believed to be remnants from the formation of the solar system, and their composition can reveal information about the conditions and materials that were present in the early solar nebula.