While Jupiter is nowhere near massive enough to initiate fusion in its core, there are even more massive objects out there that fall just short of that achievement as well called brown dwarfs. Brown dwarfs, have a mass that places them between giant planets and small stars. They were only recently discovered in the 1990’s, but thousands are now known. More massive ones can fuse deuterium, and even lithium, but not hydrogen, distinguishing them from “normal” stars. Sort of.

Correction: In the illustration at 9:30, the numbers listed after the star names are the year of discovery, not distance.


Table of Contents
Intermediate in Mass 1:22
Thousands Are Known 4:48
Cannot Fuse Hydrogen Like “Normal” Stars 8:46


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The sun in extreme ultraviolet https://en.wikipedia.org/wiki/File:The_Sun_in_extreme_ultraviolet.jpg [credit: NASA, ESA / Wikimedia Commons]
Jupiter http://www.spacetelescope.org/static/archives/images/screen/heic1410a.jpg [credit: NASA, ESA, and A. Simon (Goddard Space Flight Center)]
Forming a Planetary Gap http://www.spitzer.caltech.edu/video-audio/691-ssc2004-08v3-Forming-a-Planetary-Gap [credit: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)]
Exoplanet http://uanews.org/sites/default/files/story-images/exoplanet.jpg [credit: NASA/JPL-Caltech]
A Trio of Brown Dwarfs (L/T/Y) http://www.nasa.gov/mission_pages/WISE/multimedia/pia14722.html [credit: NASA/JPL-Caltech]
Artist's concept of a T-type brown dwarf https://en.wikipedia.org/wiki/Brown_dwarf#/media/File:2MASSJ22282889-431026.jpg [credit: NASA/JPL-Caltech]
Brown Dwarf Gliese 229B https://en.wikipedia.org/wiki/File:Brown_Dwarf_Gliese_229B.jpg [credit: NASA / Wikimedia Commons]
Gliese 229B Spectrum - image provided by Phil Plait [credit: NASA/ESA/Hubble/Al Schultz et al]
Artist's vision of a T-dwarf https://en.wikipedia.org/wiki/Brown_dwarf#/media/File:T-dwarf-nasa-hurt.png [credit: R. Hurt/NASA - R. Hurt/NASA, Wikimedia Commons]
First Ultra-Cool WISE Brown Dwarf http://wise.ssl.berkeley.edu/gallery_firstbd.html [credit: NASA/JPL-Caltech/WISE Team]
Brown Dwarf Comparison http://www.nasa.gov/mission_pages/WISE/multimedia/pia12462.html [credit: NASA/JPL-Caltech/UCB]
Storms Expected on Brown Dwarfs http://www.spitzer.caltech.edu/images/5718-sig14-001-This-Just-In-Storms-Expected-on-Brown-Dwarfs [credit: NASA/JPL-Caltech/T. Pyle (IPAC)]
Stars and brown dwarfs closest to the Sun https://en.wikipedia.org/wiki/Luhman_16#/media/File:PIA18003-NASA-WISE-StarsNearSun-20140425-2.png [credit: NASA/Penn State University]