The comet’s coma or head of the comet . is a fuzzy mist surrounding the actual nucleus of the comet. Including the tail, the coma is all we actually see, watching the comet from the Earth.
The shape and structure of the comet’s coma
The shape of the coma can vary from comet to comet and for the same comet during its passage, depending on its distance from the Sun and the corresponding quantities of dust and gas. Pale or bright comets producing little dust and often have a round shape, and comets that produce a significant amount of cometary dust have fan-shaped or parabolic shape.
This is due to released different-sized dust grains: those that are bigger are moving to the left along the trajectory of a cometary orbit, and the smaller particles are repelled from the Sun using light pressure.
Coma has 2 main components: gas-shell and shell dust. In fact, scientists believe that comets produce almost the same amount of gas and dust. Continue reading
“Our observation was aimed at studying the chemical composition of the comet Tempel 1,” says Michael Mumma (Michael Turner) from space flight Center NASA Goddard (NASA Goddard Space Flight Center). The Mumma and his colleagues used a powerful telescope, the Keck Observatory in Hawaii for a detailed analysis of the light emitted by the gas of the comet at the moment of impact. Since each type of atoms and molecules has its own characteristic frequency of radiation, on the basis of this, scientists were able to determine the chemical composition of the comet’s nucleus.
Comets are blocks, which consist of ice and dust that move in elongated orbits. It is believed that the nucleus of the comet is gas and dust formations, remaining after the formation of the main bodies of the solar system.
When approaching the Sun, its radiation heats the comet’s nucleus, releasing dust and gas. The latter form a coma (cloud around the nucleus) and one or more tails. Repeated heating leads to the fact that disappear from the surface of the substance having a low boiling point. In fact, the nucleus of a comet is formed “crust” that is different chemically from its internal regions. This makes it difficult to determine the true composition of the comet just by studying the gas in its tail. Continue reading
The diversity of comets in the Solar system
The comet (from al-Greek. hairy, shaggy) – a small celestial body having a foggy view, orbiting the Sun in conic section with a very extended orbit. When approaching the Sun, the comet forms a coma and sometimes a tail of gas and dust.
Comets are placed into circulation periods:
At this time, found more than 400 short-period comets. Of these, about 200 were observed in more than one perihelion passage. Short-period comets (period less than 200 years) come from the region of the outer planets, moving in the forward direction for orbits lying close to the Ecliptic. Away from the Sun, comets usually do not have “tails”, but sometimes have a barely visible “to”, surrounding the core; together they are called the “head” of the comet. Approaching the Sun the head is increased and there is a tail. Many of them belong to so called family. For example, most of the short-period comets (full rotation around the Sun lasts 3-10 years) form the family of Jupiter. A little smaller of a family of Saturn, Uranus and Neptune (the latter, in particular, is the famous comet Halley). Continue reading