Brown dwarfSubstellar objectArtist's concept of a T-type brown dwarfComparison: most brown dwarfs are slightly larger in volume than Jupiter (15–20%), but are still up to 80 times more massive due to greater density. Image is to scale, with Jupiter's radius being 11 times that of Earth, and the Sun's radius 10 times that of Jupiter.Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main-sequencestars.
Solar SystemThe Solar System is the gravitationally bound system of the Sun and the masses that orbit it, most prominently its eight planets, of which Earth is one. The Solar System is an isolated single-star planetary system (not part of a larger star system) within the Milky Way Galaxy. The system formed about 4.6 billion years ago when a dense region of a molecular cloud collapsed, creating the Sun and a protoplanetary disc from which the orbiting bodies assembled.
Dwarf planetSmall planetary-mass objectNine likeliest dwarf planetsand dates of discoveryCeres (1801)Pluto (1930)Quaoar (2002)Sedna (2003)Orcus (2004)Haumea (2004)Eris (2005)Makemake (2005)Gonggong (2007)A dwarf planet is a small planetary-mass object that is in direct orbit around the Sun, massive enough to be gravitationally rounded, but insufficient to achieve orbital dominance like the eight classical planets of the Solar System.
Tidal heatingTidal heating (also known as tidal dissipation or tidal damping) occurs through the tidal friction processes: orbital and rotational energy is dissipated as heat in either (or both) the surface ocean or interior of a planet or satellite. When an object is in an elliptical orbit, the tidal forces acting on it are stronger near periapsis than near apoapsis.
PlanetLarge, round non-stellar astronomical objectThe eight planets of the Solar System with size to scale (up to down, left to right): Saturn, Jupiter, Uranus, Neptune (outer planets), Earth, Venus, Mars, and Mercury (inner planets)A planet is a large, roundedastronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself.
Kelvin–Helmholtz mechanismThe Kelvin–Helmholtz mechanism is an astronomical process that occurs when the surface of a star or a planet cools. The cooling causes the internal pressure to drop, and the star or planet shrinks as a result. This compression, in turn, heats the core of the star/planet. This mechanism is evident on Jupiter and Saturn and on brown dwarfs whose central temperatures are not high enough to undergo hydrogen fusion.
Nuclear fusionNuclear fusion is a reaction in which two or more atomic nuclei combine to form a larger nucleus. The difference in mass between the reactants and products is manifested as either the release or the absorption of energy. This difference in mass arises as a result of the difference in nuclear binding energy between the atomic nuclei before and after the fusion reaction. Active stellar cores are powered by fusion.
AsteroidMinor planet found within the inner Solar SystemNot to be confused with Astroid.Images of visited asteroids illustrating their differences: (top row) 433 Eros and 243 Ida with its moon Dactyl, (bottom row) 1 Ceres and 101955 Bennu. Sizes are not to scale.An asteroid is a minor planet that orbits within the inner Solar System or is co-orbital with Jupiter (Trojan asteroids).
StarA star is a luminous spheroid of plasma held together by self-gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night; their immense distances from Earth make them appear as fixed points of light. The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names.
Natural satelliteAstronomical body that orbits a planetThe Moon orbiting around Earth (observed by the Deep Space Climate Observatory)A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are colloquially referred to as moons, by analogy with the Moon, Earth's natural satellite.
HeatType of energy transfer "Heating" redirects here; not to be confused with Home heating or Heat wave. This article is about a type of energy transfer. For the film, see Heat (1995 film). For other uses, see Heat (disambiguation).
4 VestaSecond largest main-belt asteroidVesta (minor-planet designation: 4 Vesta) is one of the objects in the asteroid belt, with a mean diameter of 525 kilometres (326 mi). It was discovered by the German astronomer Heinrich Wilhelm Matthias Olbers on 29 March 1807 and is named after Vesta, the virgin goddess of home and hearth from Roman mythology. Vesta is thought to be the second-largest asteroid, both by mass and by volume, after the dwarf planetCeres.
Astronomical objectAn astronomical object, celestial object, stellar object or heavenly object is a naturally occurring physical entity, association, or structure that exists within the universe. In astronomy, the terms object and body are often used interchangeably.*As an Amazon Associate I earn from qualifying purchases.