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
Famous quotes containing the words types and, types and/or attributes:
“The bourgeoisie loves so-called “positive” types and novels with happy endings since they lull one into thinking that it is fine to simultaneously acquire capital and maintain one’s innocence, to be a beast and still be happy.”
—Anton Pavlovich Chekhov (1860–1904)
“As for types like my own, obscurely motivated by the conviction that our existence was worthless if we didn’t make a turning point of it, we were assigned to the humanities, to poetry, philosophy, painting—the nursery games of humankind, which had to be left behind when the age of science began. The humanities would be called upon to choose a wallpaper for the crypt, as the end drew near.”
—Saul Bellow (b. 1915)
“Even though fathers, grandparents, siblings, memories of ancestors are important agents of socialization, our society focuses on the attributes and characteristics of mothers and teachers and gives them the ultimate responsibility for the child’s life chances.”
—Sara Lawrence Lightfoot (20th century)