Cosma Home > Communication > Knowledge > Realm > Physical > Universe > Planetary System > Brown Dwarf
Spotlight
Related
Pages
Physical Realm
Universe Astronomical Instrument
Galaxy Milky Way, Andromeda
Planetary System Star, Brown Dwarf, Planet, Moon
Solar System Sun
Terrestrial Planet Mercury, Venus, Earth (Moon), Mars
Asteroid Belt Ceres, Vesta
Jovian Planet Jupiter, Saturn, Uranus, Neptune
Trans-Neptunian Object
Kuiper Belt Pluto, Haumea, Makemake
Scattered Disc Eris, Sedna, Planet X
Oort Cloud Etc. Scholz’s Star
Small Body Comet, Centaur, Asteroid
Resources
These are organized by a classification scheme developed exclusively for Cosma. More…
General
Encyclopedia
Brown dwarf is a substellar object that occupies the mass range between the heaviest gas giant planets and the lightest stars, having masses between approximately 13 to 75–80 times that of Jupiter (MJ), or approximately 2.5×1028 kg to about 1.5×1029 kg. Below this range are the sub-brown dwarfs, and above it are the lightest red dwarfs (M9 V). Brown dwarfs may be fully convective, with no layers or chemical differentiation by depth.
Unlike the stars in the main sequence, brown dwarfs are not massive enough to sustain nuclear fusion of ordinary hydrogen (1H) to helium in their cores. They are, however, thought to fuse deuterium (2H) and to fuse lithium (7Li) if their mass is above a debated threshold of 13 MJ and 65 MJ, respectively. It is also debated whether brown dwarfs would be better defined by their formation processes rather than by their supposed nuclear fusion reactions.
Stars are categorized by spectral class, with brown dwarfs designated as types M, L, T, and Y.[ Despite their name, brown dwarfs are of different colors. Many brown dwarfs would likely appear magenta to the human eye, or possibly orange/red. Brown dwarfs are not very luminous at visible wavelengths.
There are planets known to orbit brown dwarfs: 2M1207b, MOA-2007-BLG-192Lb, and 2MASS J044144b.
At a distance of about 6.5 light years, the nearest known brown dwarf is Luhman 16, a binary system of brown dwarfs discovered in 2013. HR 2562 b is listed as the most-massive known exoplanet (as of December 2017) in NASA’s exoplanet archive, despite having a mass (30±15 MJ) more than twice the 13-Jupiter-mass cutoff between planets and brown dwarfs. — Wikipedia
Introduction
Search
Education
Course
Crash Course Astronomy (YouTube)
OER Commons: Open Educational Resources
Library
WorldCat, Library of Congress, UPenn Online Books, Open Library
News
Book
Government
Document
More…
Phys.org - latest science and technology news stories Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.
-
Extraordinary treefrog discovered in the Andes of...
on January 3, 2019 at 6:53 am
A new treefrog species was discovered during a two-week expedition to a remote tabletop mountain at Cordillera del Cóndor, a largely unexplored range in the eastern Andes. […]
-
Sinking Greek village highlights nation's...
on December 19, 2018 at 8:26 am
If earthquakes struck in slow motion, the results might be visible in a place like the Greek village of Anargyri, a hardscrabble enclave in a black landscape gutted by coal mining. […]
-
229 new species described by the California...
on December 5, 2018 at 6:24 pm
In 2018, researchers at the California Academy of Sciences added 229 new plant and animal species to our family tree, enriching our understanding of Earth's complex web of life and strengthening our ability to make informed conservation decisions. The new species include 120 wasps, 34 sea slugs, 28 ants, 19 fish, seven flowering plants, seven spiders, four eels, three sharks, two water bears, one frog, one snake, one seahorse, one moss, and one liverwort plant. More than a dozen Academy […]
-
First light for SPECULOOS
on December 5, 2018 at 6:13 pm
The SPECULOOS Southern Observatory (SSO) has been successfully installed at the Paranal Observatory and has obtained its first engineering and calibration images—a process known as first light. After finishing this commissioning phase, this new array of planet-hunting telescopes will begin scientific operations, starting in earnest in January 2019. […]
-
Astronomers detect low-mass brown dwarf around...
on December 3, 2018 at 2:10 pm
Using HATSouth Exoplanet Survey, an international group of astronomers has discovered a low-mass brown dwarf transiting an A-type main-sequence star. The newly detected brown dwarf, designated HATS-70b, is the first such object found around a star of this type. The finding is detailed in a paper published November 16 on arXiv.org. […]