A fusor is a term proposed to the IAU

IAU

IAU may refer to:*International Astronomical Union*International American University*International American University College of Medicine*International Association of Universities*International Association of Ultrarunners...

 by Gibor Basri

Gibor Basri

Gibor Basri is an American astrophysicist, born in New York on May 3, 1951.The son of Phyllis Basri, a professor of dance and ballet, and Saul Basri, professor of physics at the University of Colorado, Basri grew up in Fort Collins, Colorado, together with his younger brother David...

, Professor of Astronomy at the University of California, Berkeley

University of California, Berkeley

The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...

, to help clarify the nomenclature of celestial bodies. Under his definition a fusor would be "an object that achieves core fusion during its lifetime." This definition included any form of nuclear fusion

Nuclear fusion

Nuclear fusion is the process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. This is usually accompanied by the release or absorption of large quantities of energy...

 so the lowest possible mass of a fusor was set at roughly 13 times that of Jupiter

Jupiter

Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...

, at which point deuterium

Deuterium

Deuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...

 fusion becomes possible. This is significantly smaller than the point at which sustained fusion of hydrogen

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 becomes possible, around 60 times the mass of Jupiter. Objects aren't considered "stellar" until around 75 times the mass of Jupiter, when gravitational contraction, i.e., contraction of the object due to gravity, is halted by heat generated by the internal nuclear reaction.

See also

• Gas Giant
  Gas giant
  A gas giant is a large planet that is not primarily composed of rock or other solid matter. There are four gas giants in the Solar System: Jupiter, Saturn, Uranus, and Neptune...
  
  
• Exoplanet
• Dwarf planet
  Dwarf planet
  A dwarf planet, as defined by the International Astronomical Union , is a celestial body orbiting the Sun that is massive enough to be spherical as a result of its own gravity but has not cleared its neighboring region of planetesimals and is not a satellite...
  
  
• Mesoplanet
  Mesoplanet
  Mesoplanet is a term coined by Isaac Asimov to refer to planetary bodies with sizes smaller than Mercury but larger than Ceres. Assuming "size" is defined by linear dimension , mesoplanets should be approximately 1,000 km to 5,000 km in diameter...
  
  
• Planetesimal
  Planetesimal
  Planetesimals are solid objects thought to exist in protoplanetary disks and in debris disks.A widely accepted theory of planet formation, the so-called planetesimal hypothesis of Viktor Safronov, states that planets form out of cosmic dust grains that collide and stick to form larger and larger...
  
  
• Planetoid
• Planetar (astronomy)
  Planetar (astronomy)
  Planetar is a term used in astronomy that refers to one of two things:* Brown dwarfs — objects intermediate in size between planets and stars — but having formed similarly to planets....
  
  
• Pulsar planet
  Pulsar planet
  Pulsar planets are planets that are found orbiting pulsars, or rapidly rotating neutron stars. The first such planet to be discovered was around a millisecond pulsar and was the first extrasolar planet to be confirmed as discovered.-Pulsar planets:...