COURSE Introduction to Astronomy (37) THE CLASSIFICATION OF COMETS.
The comets are designated by a nomenclature, ie the name of its discoverer / s (maximum three discoverers), followed by the year of discovery and a lowercase letter indicating the number of order appearance of the comet within the year. When one considers the orbital data of the same, the year is replaced per year of perihelion passage, followed by a roman numeral indicating the order number that step.
For a comet should be visible close to the sun, this causes changes in the kite making it visible to the telescope, if weak, or if it's bright eye. Typical and morphologically
a comet consists of:
1) Nucleo.
2) Eat or hair.
3) tail or tails.
often appear devoid of comet tails, particularly those who have already taken many turns to the sun gradually losing some of its mass. In other cases show a spike or spike on the opposite side to the tail. The most widely accepted among astronomers is that the core is a dirty snowball, assuming that the nucleus of a comet is a ball of ice mixed with dust particles. The dimensions of the core can vary between 1 and 100 km.
When a comet approaches the Sun, solar radiation, evaporation of the ice cream core material. In this evaporation process arising paricular thus forming a dust cloud of gas and dust surrounding the nucleus. This cloud is the comet's coma coma diameter can reach 100,000 km.
The coma is visible through two processes: first, the comet's dust reflects sunlight, on the other hand, the molecules dissociate gas due to solar radiation and become fluorecientes, emitting light.
COURSE Introduction to Astronomy (36) THE ORBIT OF COMETS.
Comets can describe three types of orbits:
1) ellipticals.
comets whose orbits are elliptical with periodic character, moving around the Sun, which occupies one focus. As a rule, their eccentricities are large. Some comets have relatively short orbital periods as in the case of comet Encke, with a period of 3.3 years while others have hundreds of years.
Because comets have masses very small gravitational influences of the planets with almost nil. On the contrary, due to the gravitational perturbations of the Sun and some giant planets, Jupiter and Saturn in particular is very common that the comet's orbital period alters, through changes, sometimes dramatic. One of the disturbance is the capture of comets by planets, which can be placed aphelion far beyond Pluto (periodic comets) by transforming them into short-period comets than they did, whose aphelion is within the Solar System. Catch these families originate from comets like Jupiter, made up of more than 60 members whose aphelion is located near the orbit of Jupiter. There are also families of Saturn, Uranus, Neptune and Pluto.
2) Hyperbolic.
3) Parabolic.
Comets with parabolic and hyperbolic orbits are not periodic since their curves are not cerradas.Luego appear only once emerging from the depths of space, they approach the sun and away from it and disappeared forever.
The orbit of comets have very different angles on the plane of the ecliptic. Guna them to have an inclination greater than 90 ° so that the comets that have moved in a retrograde, such as Halley's comet.
COURSE Introduction to Astronomy (35) comets. Formerly
to comets have been related to adverse events, wars, epidemics. The word comet comes from the Greek for "hair", referring to the morphology of these stars.
Currently, the most accepted hypothesis is that made by the astronomer Oort, that there is a vast region of space located between 40,000 and 150,000 AU in which there are 100,000,000,000 cometary nuclei, called the Oort Cloud. Due to sporadic disturbances caused by the next step of some star, some of these nuclei can be propelled into the Solar System. One of them would approach the Sun as hyperbolic or parabolic orbits and move away then disappearing. Other cores, due to the gravitational influence of the Sun and planets like Jupiter and Saturn, would be captured and become periodic elliptical orbits. After completing a large number of orbits and revolutions around the Sun and would have spent their stuff and would eventually disappear by the continuous wear.
