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The coma is generally made of water and dust, with water making up to 90% of the volatiles that outflow from the nucleus when the comet is within 3 to 4 astronomical units (450,000,000 to 600,000,000 km; 280,000,000 to 370,000,000 mi) of the Sun. [50] The H 2 O parent molecule is destroyed primarily through photodissociation and to a much ...
The nucleus of Comet Tempel 1. The nucleus is the solid, central part of a comet, formerly termed a dirty snowball or an icy dirtball. A cometary nucleus is composed of rock, dust, and frozen gases. When heated by the Sun, the gases sublime and produce an atmosphere surrounding the nucleus known as the coma.
The vaporized ices later resolidified and assembled into comets. So the comets in this model would have a different composition than those comets that were made directly from interstellar ice. The 3) primordial rubble pile model for comet formation says that comets agglomerate in the region where Jupiter was forming.
The coma is generally made of ice and comet dust. [1] Water composes up to 90% of the volatiles that outflow from the nucleus when the comet is within 3–4 au (280–370 million mi; 450–600 million km) from the Sun. [1] The H 2 O parent molecule is destroyed primarily through photodissociation and to a much smaller extent photoionization. [1]
While the solid nucleus of comets is generally less than 30 km across, the coma may be larger than the Sun, and ion tails have been observed to extend 3.8 astronomical units (570 Gm; 350 × 10 ^ 6 mi). [6] The Ulysses spacecraft made an unexpected pass through the tail of the comet C/2006 P1 (Comet McNaught), on February 3, 2007. [7]
The passage of Earth through cosmic debris from comets and other sources is a recurring event in many cases. Comets can produce debris by water vapor drag, as demonstrated by Fred Whipple in 1951, [60] and by breakup. Each time a comet swings by the Sun in its orbit, some of its ice vaporizes and a certain amount of meteoroids are shed. The ...
These bodies, larger than 100 km to 1000 km, are called embryos or protoplanets. [ 9 ] In the current Solar System, these small bodies are usually also classified by dynamics and composition, and may have subsequently evolved [ 10 ] [ 11 ] [ 12 ] to become comets, Kuiper belt objects or trojan asteroids , for example.
Near-Earth comets (NECs) are objects in a near-Earth orbit with a tail or coma made up of dust, gas or ionized particles emitted by a solid nucleus. Comet nuclei are typically less dense than asteroids but they pass Earth at higher relative speeds, thus the impact energy of a comet nucleus is slightly larger than that of a similar-sized ...