The Brown Dwarfs are entities existing between the heaviest planets and the lightest starts and have masses approximately 13 to 75 times of Jupiter. Because of their unique existence, the Brown Dwarfs may be entirely convective, hence lacking chemical differentiation and layers or fully convective. Unlike the starts which have a sequential existence , Brown Dwarfs lack the necessary amount of mass sufficient enough to support nuclear fusion in there cores. Particularly, ordinary hydrogen (H) cannot undergoes undergo nuclear reaction and form helium at the core of the Brown Dwarfs.
Despite the tiny amount of mass, advanced astronomical research has found out that some Brown Dwarfs with threshold mass fuse lithium (Li) and deuterium (H) (Kirkpatrick 19). Because of broader understanding of their formation processes, the processes of formation provides a concise and accurate definition of the Brown Dwarfs as compared to the supposed nuclear reaction in their cores. Since 1960s, there has been a gradual increase in the scope of interest on Brown Dwarfs. Particularly, they have attracted astronomical research. Therefore, an in-depth and explicit illustration of the basic aspects and elaborate perspectives of the Brown Dwarfs is necessary in understanding their role within the wider scope of astronomical research.
Primarily because of the inconclusive research and insufficient information about the Brown Dwarfs, astronomers unanimously agreed to call them “Brown Dwarfs” to the heavenly bodies. Lack of agreement regarding the origins, physical, and chemical properties of the Brown Dwarfs led to significant disagreement among astronomers. Lack of convincing understanding among prominent astronomers in the 1970s led to the naming of the bodies as Brown Dwarfs (Kirkpatrick 19). Apart from the conventional agreement on the name Brown Dwarfs, other factions of astronomers proposed names such as infrared dwarfs, Lilliputian stars, substellar objects, super-Jupiter, failed stars, and black stars.
Despite the preliminary confusion and failure of reaching definitive agreement among scientist, recent advanced research on Brown Dwarfs has led to explorative studies on cosmological perspectives of the black matter (Marley 279). While a significant number of astrologers doubted the actual existence of the Brown Dwarfs, advanced astronomical research studies and discoveries unraveled the hidden aspects of the substellar objects. For example, in 1995, astronomers formally announced the discovery of a cool and black object. Subsequently, discoveries of three young dwarfs cleared the previous doubts on the existence of the substellar objects. The further astronomical research discovered over 100 varying masses and ages of Brown Dwarfs. Additionally, astronomers added two entirely new spectral categories to the classification scheme in half a century, thereby leading the development of astrophysics as a subfield of astronomy (Luhman 106).
Properties of Brown Dwarfs
Several groups of astronomers have embarked on concerted efforts to examine and understand the fundamental properties of the Brown Dwarfs. For example, calculations by different astronomers have realized that the lowest mass of a brown dwarf is 8 percent the mass of the sun. Also, the luminosity of such a brown dwarf was 10-4 times that of the sun (Luhman 102). Even though a significant majority of Brown Dwarfs has luminosities that are relatively higher than the above conventional value, the majority of them cool, hence reduce in brilliance and size. Through the determination of the mass of the Brown Dwarfs, astronomers discovered the approximate radius of an ordinary brown dwarf to be 10 percent that of the earth.
The “L Dwarfs”
Since the older Brown Dwarfs are cooler and less brilliant than the young ones, distinguishing the young ones from the stars is relatively difficult. Despite the challenge of differentiating between the young Brown Dwarfs and the stars, there is an essential diagnostic model. High temperatures nuclear reactions transmit the fragile lithium in the stars, a phenomenon that is absent in Brown Dwarfs cores. Certainly, there is no lithium transmutation among Brown Dwarfs with very approximately 6 percent the mass of the sun (Faherty 36). On the other hand, those with 6 and 8 % the mass of the san transmute a relatively more significant fraction of their lithium because their masses can sustain high-temperature nuclear fusion in their first 50 to 200 million years (Luhman 68).
Even though the youngest Brown Dwarfs closely resembles low-mass stars, the Brown Dwarfs will illustrate unique properties of lithium as opposed to the stars (Luhman 79). In 1995, the spectroscopic observation that astronomers undertook in Hawaii revealed telltale attributes of the presence of lithium in peculiar luminous objects. Indeed, these were the first young Brown Dwarfs that astronomers identified and named them Calar 3, Teide 1, and PPL 15. Apart from the preliminary findings, further discoveries have identified more young Brown Dwarfs in the Pleiades (Marley 302).
The T “Dwarfs”
Tadashi Nakijama was the first astronomer to discover the old and cold Brown Dwarfs in Palomar Observatory, California. Notably, Tadashi and co-workers discovered an object adjacent to the giant star, Gliese that was located approximately 17 light-years from the sun. Apart from its distant position from the sun, the cold and old Brown Dwarfs had a luminosity of 6 by 10-6 that of the sun. A systematic survey of adjacent stars led to the discovery of the Gielese 229B.
Given the astronomical relevance of the Brown Dwarfs, there is an imperative need to understand the chemical and physical attributes. Such discoveries will advance astronomical research and broaden the scope of discovery of various extraterrestrial entities within the universe. Additionally, advanced research on Brown Dwarfs will widen the scope of discovery on the stars and understand the fundamental differences between the two bodies.
