Types and Attributes
With the increasing discovery of planetary systems, astronomers have begun to classify them by type. In particular, as certain types of stars are now known for producing specific types of planetary systems, they are classified by the spectral type of the host star. Main-sequence stars like the Sun (spectral type G or K), for example, have represented the majority of planetary system discoveries. Additionally, they are often classified by the size and types of planets and their orbital configuration. Hot Jupiter systems with a gas giant very close in to the star are one of the most common found so far and Hot Neptune type systems have also been found. Theories, such as scattering, have been proposed for the formation of large planets close in to their parent stars. Dusty disks with a wide ring of dust and comets are another common type of system. Protoplanetary disks, still in the process of forming have also been discovered. At present, few systems have been found to analogues of our own with terrestrial planets close in to the parent star. More commonly, systems consisting of multiple Super-Earths have been detected.
Read more about this topic: Planetary System
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