Question

Consider the following about Brown Dwarf:
1. It is a small star that is somewhat cooler than a Red Dwarf.
2. It is a very large planet.
Which of the above statements is/are true?
A. Only one
B. Only two
C. Both 1 and 2
D. None of these

Answer 1

Hint:Brown dwarfs, despite their name, come in a variety of hues depending on their temperature. Warmer brown dwarfs may seem orange or red, whereas colder brown dwarfs may appear magenta to the naked eye. Brown dwarfs might be completely convective, with no layers or chemical differentiation at various depths.

Complete step by step answer:
Brown dwarfs, unlike main sequence stars, are substellar objects with insufficient mass to support nuclear fusion of ordinary hydrogen into helium in their cores. They range in mass from 13 to 80 times that of Jupiter, and are found between the most massive gas giant planets and the least massive stars.

They can, however, fuse deuterium, and the most enormous of them can fuse lithium. Shiv S. Kumar proposed the existence of "brown dwarfs" in the 1960s, and they were originally classified as "black dwarfs," which were dark substellar objects floating freely in space that were not big enough to support hydrogen fusion.

The mass of red dwarfs ranges from 7.5 percent to 50 percent that of the Sun. Although somewhat more massive stars are occasionally considered, our Sun is far too big. None of them has more than a hundredth of the Sun's brightness, and some of the smallest red dwarfs can glow for billions of years due to their extremely low rate of fuel use (our Sun will last a total of only about 10 billion years). At 4.2 light years away, Proximal Centauri, the closest star outside of our Sun, is a red dwarf.

Brown dwarfs lack the capacity to fuse common hydrogen, but they can fuse deuterium and lithium, which are less prevalent isotopes. Brown dwarfs have a much lower luminosity than red dwarfs. They are classified as "substellar objects," as opposed to red dwarfs, which are complete stars. Brown dwarfs are more easily identified via infrared emissions rather than being observed visually, even with powerful telescopes, because of their low brightness and very low temperatures. 6.5 light years distant is the closest (known) brown dwarf.

Hence,the correct option C.

Note:In the late 1980s, the finding of deuterium burning down to 0.013 solar masses, as well as the influence of dust generation in the cold outer atmospheres of brown dwarfs, cast doubt on these hypotheses. However, because they produce practically little visible light, such things are difficult to locate. Their greatest emissions occur in the infrared band, and ground-based IR detectors were too inaccurate to discover any brown dwarfs at the time.