Solar System Sun
Terrestrial Planet Mercury, Venus, Earth (Moon), Mars
Asteroid Belt Ceres, Vesta
Jovian Planet Jupiter, Saturn, Uranus, Neptune
Kuiper Belt Pluto, Haumea, Makemake
Scattered Disc Eris, Sedna, Planet X
Oort Cloud Etc. Scholz’s Star
Small Body Comet, Centaur, Asteroid
These are organized by a classification scheme developed exclusively for Cosma. More…
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
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Citizen scientists spot closest young brown dwarf...
on June 2, 2020 at 7:00 pm
Brown dwarfs are the middle child of astronomy, too big to be a planet yet not big enough to be a star. Like their stellar siblings, these objects form from the gravitational collapse of gas and dust. But rather than condensing into a star's fiery hot nuclear core, brown dwarfs find a more zen-like equilibrium, somehow reaching a stable, milder state compared to fusion-powered stars.
Astronomers create cloud atlas for hot,...
on May 26, 2020 at 5:21 pm
Giant planets in our solar system and circling other stars have exotic clouds unlike anything on Earth, and the gas giants orbiting close to their stars—so-called hot Jupiters—boast the most extreme.
Astronomers find Jupiter-like cloud bands on...
on May 5, 2020 at 5:34 pm
A team of astronomers has discovered that the closest known brown dwarf, Luhman 16A, shows signs of cloud bands similar to those seen on Jupiter and Saturn. This is the first time scientists have used the technique of polarimetry to determine the properties of atmospheric clouds outside of the solar system, or exoclouds.
NASA's Webb Telescope to unravel riddles of a...
on April 30, 2020 at 4:40 pm
A bustling stellar nursery in the picturesque Orion Nebula will be a subject of study for NASA's James Webb Space Telescope, scheduled to launch in 2021. A team led by Mark McCaughrean, the Webb Interdisciplinary Scientist for Star Formation, will survey an inner region of the nebula called the Trapezium Cluster. This cluster is home to a thousand or so young stars, all crammed into a space only 4 light-years across—about the distance from our Sun to Alpha Centauri.
10 years after BP spill: Oil drilled deeper;...
on April 18, 2020 at 8:27 pm
Ten years after an oil rig explosion killed 11 workers and unleashed an environmental nightmare in the Gulf of Mexico, companies are drilling into deeper and deeper waters, where the payoffs can be huge but the risks are greater than ever.