CyberWorld

What are Dwarf Planets?

A dwarf planet looks like a regular planet, but is not one. These planets are independent bodies in the solar system which are large enough to flaunt individual geological and planetary processes. They have the ability to grow from 'irregular' to 'round' on account of the transition made possible by each one's gravitational pull.

Facts about Dwarf Planets:

The International Astronomical Union (IAU), defines a dwarf planet as a celestial body that orbits the Sun. It is further defined to be massive enough to use its own gravitational force to become round or spherical in time. These planets are believed to be inclusive of the surrounding planetesimals and devoid of individual satellites. Ideally, a dwarf planet is one that is capable of overcoming its compressive strength with the help of its mass, to achieve the required hydrostatic equilibrium. A dwarf planet is not a minor planet. Dwarf planets are in-between accepted planets or large bodies with cleared orbits and small solar system bodies. The term was coined in 2006 by the IAU and remains disputed.

The IAU officially recognizes five dwarf planets: Pluto, Ceres, Haumea, Eris and Makemake. Though only Ceres and Pluto have been observed in detail, Eris has been accepted within the category since it is bigger than Pluto. Makemake and Haumea have been accepted as dwarf planets since they display absolute magnitude of less than +1 and a minimum diameter of 838km, conditions set by the IAU. These planets are characterized by large orbital eccentricity and orbital inclination. The Alan Stern and Harold F. Levison parameter called 'Λ' or lambda, is used to estimate whether or not small terrestrial planets qualify as dwarf planets. Soter's planetary discriminant that is identified by the symbol µ or mu, represents the measure of actual orbital cleanliness, by dividing the mass of the 'studied dwarf planet' by the total mass of the objects in its orbital zone.

Research reveals three distinct dwarf planets. The asteroid Ceres, planet Pluto and Eris are considered dwarf planets. However, there are a number of other 'identified round and irregular objects' in the solar system that qualify as dwarf planets, by definition. There are a number of new dwarf planets sighted in the Kuiper belt. While there is no definite estimate on how big a celestial object has to be to qualify as a dwarf planet, the asteroid belt Ceres gives us a diameter of 900 km as a good demarcation. Research conducted in August 2006 revealed that there are more than 40 objects in the Kuiper belt that qualify as dwarf planets. The Palomar survey is dedicated to a detailed study of more than 30 of these identified objects.

Scientists agree on the presence of more than 50 round objects in the solar system, which could culminate in the study of more than 200 once the Kuiper belt is completely and systematically surveyed. It is believed that beyond the Kuiper belt, the Sedna region may contain more than 2000 dwarf planets. The dwarf planets identified in the solar system are so small, that measured dynamics and dimensions reveal that about 30,000 such planets could fit within the earth's diameter. Ceres was the first dwarf planet to be discovered by Piazzo, in 1801. Thereafter Pluto was studied by Tombaugh in 1930, triggering the study of objects in the Kuiper belt in the 1990s. The Brown et al. study revealed the presence of around fifteen dwarf planets, while the Deep Ecliptic Survey studies eight. Near-Earth Asteroid Tracking Survey is credited with the survey of four dwarf planets, while Spacewatch and Jewitt et al. are credited with details on more than three dwarf planets each.