Supernova

A supernova is an explosion of a star. In Universe Sandbox, a star will become a supernova in the following scenarios:
 * The Explode tool is used on a star
 * The mass of a white dwarf is increased to greater than 1.4 Solar masses
 * Two stars collide
 * A star collides with a non-star object whose mass is at least 5% of the star's mass
 * A star is set to supernova after a certain amount of time in a prebuilt simulation

At the moment of a supernova, a bright glow will appear and a number of Supernova Cloud objects will be produced at the location of the original star, also known as the progenitor. Depending on the type of supernova, the Star object may become a stellar remnant, or it may be removed from the simulation. The clouds will expand outwards from the origin point of the supernova, heating any Planetary Body objects that they pass.

Properties
Properties related to the original star and the resultant clouds, including the Supernova Type, Cloud Mass, and Origin location, are located in the Nova tab in the properties panel of any of the Supernova Cloud objects.

Settings
Supernova Clouds and the bright glow of supernovae can be hidden using the Supernovae toggle in the View Settings Menu.

Type II
A Type II supernova results from the collapse of a massive star.

In Universe Sandbox, a Type II supernova is produced when a supernova is triggered for a star with a mass of at least 8 times the mass of the Sun. The original Star object will have "Nova Remnant" appended to its name, and its mass will be decreased. If the remnant mass is greater than or equal to 5 Solar masses, the remnant object will be a Black Hole rather than a Star.

Type Ia
A Type Ia supernova results when a white dwarf gains enough mass to collapse and trigger a runaway thermal reaction.

In Universe Sandbox, a Type Ia supernova is produced when a supernova is triggered for a star with a mass less than 8 Solar masses. It will also occur when the mass of a white dwarf star is increased to be greater than the Chandresekhar limit of 1.4 Solar masses, either by collisions with smaller objects or by directly changing the Mass property of the star.

A Type Ia supernova will leave behind no remnant, and the original star will be removed from the simulation.

Other Supernova Types
Universe Sandbox does not simulate less common supernova types, such as Type Ib or Ic supernovae.

Unrealistic Progenitor Masses
In reality, stars like the Sun with masses less than 8 Solar masses will never become supernovae. However, in the spirit of allowing a user to explore scenarios like a supernova in the Solar System, Universe Sandbox allows for supernovae of these smaller-mass stars. In this case, Universe Sandbox simulates the supernova as a Type Ia supernova, even though the original star may not be a white dwarf.