Editing Brown dwarf (section)

==== Heat spectrum ====
X-ray and infrared spectra are telltale signs of brown dwarfs. Some emit [[X-ray]]s; and all "warm" dwarfs continue to glow tellingly in the red and [[infrared]] spectra until they cool to planet-like temperatures (under {{val|1000|u=K}}).

[[Gas giant]]s have some of the characteristics of brown dwarfs. Like the Sun, [[Jupiter]] and [[Saturn]] are both made primarily of hydrogen and helium. Saturn is nearly as large as Jupiter, despite having only 30% the mass. Three of the giant planets in the Solar System (Jupiter, Saturn, and [[Neptune]]<!-- Uranus emits only barely more heat than it receives from the Sun, per source -->) emit much more (up to about twice) heat than they receive from the Sun.<ref>{{cite web |url=http://astronomy.nmsu.edu/tharriso/ast105/UranusandNeptune.html |title=The Jovian Planets: Uranus, and Neptune |access-date=2013-03-15 |archive-url=https://web.archive.org/web/20120118184803/http://astronomy.nmsu.edu/tharriso/ast105/UranusandNeptune.html |archive-date=2012-01-18 |url-status=dead }}</ref><ref>{{cite web |url=http://coolcosmos.ipac.caltech.edu/cosmic_classroom/cosmic_reference/planets.html |title=Cool Cosmos – Planets and Moons |access-date=2019-02-11 |archive-date=2019-02-21 |archive-url=https://web.archive.org/web/20190221171452/http://coolcosmos.ipac.caltech.edu/cosmic_classroom/cosmic_reference/planets.html |url-status=dead }}</ref> All four giant planets have their own "planetary" systems, in the form of extensive moon systems.