Meteors and Comets-Comets

Comets get its name from the Greek word kometres, which means “long-haired.” A comet is a tiny body that orbits all around the sun and therefore consists of volatile ices plus dust particles. When a comet moves close to the sun, its frosts dissolve then turn into dust particles. The coma is a brighter outflowing atmosphere that surrounds the comet nucleus after the comets are lighted. The comet’s dust and gas particles freely travel into space, forming two tails. Molecules including radicals are found in one tail of the coma, whereas dust particles are located in another.

Comets Origin

Comets are the most awe-inspiring celestial bodies. They have vivid blazing comae, extended dust, and ion tails—comets in the solar system orbit the sun in highly eccentric orbits with their orbits. The gravity of the sun or the planets’ gravity in the solar system usually dominates the movement of comets. Many scientists have studied comets & discovered that they are the primitive remnant bodies from the solar system’s creation. Comets, they believed, should have been the first solid bodies to develop in a solar nebula. Comets in their orbit are frequently disturbed by solar radiation created in the universe. The majority of comets are six astronomical units distant from Jupiter’s orbit.

Furthermore, most comets orbit further than the planets in a vast orbit. Due to a change in the solar system, such comets may experience physical changes such as melting. The comets’ physical or chemically modified records have also been preserved in the solar nebula.

Comets Orbits

Comets were generally unique from other bodies in the solar system. Like planets or other asteroids, Comets revolve around the sun with a much more eccentric orbit than planets and asteroids. Comets occasionally approach a distance of 50,000 AU, which would be a significant fraction of the distance between the closest star. Based on the length of the orbit, the comet’s orbital period will range from those few years to millions of years. Comets with short orbital periods will be carried closer to Jupiter and Saturn’s terrestrial planets. Certain comets would also traverse across interstellar space upon open hyperbolic circular orbits.

Why Comets? 

Comets are extremely important and extraordinary objects due to their amount of volatile material. This feature indicates these comets formed at a great distance from the Sun and have been kept at low temperatures during formation. As a result, cometary material is the closest we could approach the conditions prevailing when the Sun and our Solar System were created. 

In the previous decade, the number of telescope observations from the ground or even in Earth orbit (for example, from the ESA/NASA SOHO and Hubble Space Telescope projects) has risen. They constitute the foundation for comprehending these small bodies, as we can now compare observations of a wide range of objects and conduct more extensive cometary studies.

Types of Comets

The orbital period is one of the simplest methods to classify it. They are divided into two types in terms of their most fundamental classification. There are two types of comets: short-period comets or long-period comets.

Short Period Comets

Comets with orbital periods of less than 200 years are short-period comets. They also usually have a less than 35-degree inclination. Although 200 years may seem like a long time, it is relatively brief in cometary terms. They are easier to catalogue or forecast once discovered than long-period comets. With an orbital period of 75-76 years, Comet Halley is the most well-known short-period comet. Short-period comets are thought to have originated in the Kuiper belt. Short-period comets are divided into two groups: Halley Type (with a period of more than 20 years) and Jupiter Type (with a period of fewer than 20 years) (with a period of under 20 years). Comets with short periods may well have circular or elliptical orbits. The latter is significantly more prevalent.

Long Period Comets

On the other hand, long-period comets are assumed to begin from the Oort cloud and have periods of over 200 years, orbiting the celestial sphere at unpredictable angles. They are challenging to discover and categorise since they can return after thousands or even millions of years (or not at all). Comets with long periods can have even more irregular orbits due to their random orientation on the celestial sphere. They can take hundreds to millions of years (or never) to retrace their paths, making them difficult to identify and classify.

Conclusion

When a comet gets close to the sun, it warms up and begins to release gases trapped inside it: this is known as outgassing, which gives a comet its narrative. The comet’s nucleus is influenced by solar radiation and solar wind, resulting in this phenomenon. The coma has a diameter of about fifteen times that of the Earth, and also its tail reaches one astronomical unit. I hope now you understand all about comets. For better understanding, you must go through this topic properly.