4.2 Stellar Phenomena

These are some of the things that happen over the lifetime of various types of stars.

accretion bridge: A stream of material, usually hot plasma or gasses, that can flow from one star in a binary pair to its companion star. (See "Evolution.") See also: binary star pair.

accretion disk: A frisbee-shaped agglomeration of gases and material found around one of the stars in some binary star systems and around supermassive black holes.

antimatter star: Or an antimatter nebula. Possibly originating from outside our galaxy, it is possible that an entire star could be composed of antimatter. If the entire star and its planets were pure antimatter, it would have a perfectly normal existence unless it came into contact with something composed of "normal" matter. Like Voyager. Possibly more insidious would be a gas cloud or nebula composed of anti-hydrogen. Although very thin (like a regular nebula), such a cloud might cause severe erosion of the ship's hull as it flew through.

binary star pair: Many stars in our galaxy are what we call binary pairs. That is, they orbit each other. In some such binary pairs, the gravity of one star is so great that it actually pulls gas from the other star's photosphere. These streamers of ionized gas would be very spectacular and would be a threat to any spacecraft or planet in the vicinity. Used.

binary star, cataclysmic: A binary star system which undergoes violent periods of nova outbursts caused by one star passing too close to its companion.

binary star, contact: A pair of stars orbiting so close to each other that their inner atmospheres touch.

bipolar outflow: A stage in the formation of young stars in which streams of material are ejected from the north and south poles of the star. Also associated with cataclysmic binary stars and supermassive black holes.

black dwarf: The cold, burnt-out remains of a white dwarf star. Believed to be one of the oldest types of objects in the universe.

black hole: One of the most fearsome objects in nature. This is a dead star which was once larger than our Sun. After it burnt out, it gravitationally collapsed onto itself. So powerful was its gravity that it finally collapsed into an object smaller than an atom's nucleus. The resulting "black hole" is so-named because its gravity is so great than even light cannot escape. Near a black hole, this incredible gravity also causes terrible tidal stresses — more than enough to tear a planet or a starship to shreds. There would also be very severe (and probably dangerous) time/space distortions near the black hole. A wandering black hole is very capable of swallowing entire solar systems. (Note: It is very unlikely that any object or ship could survive falling "through" a black hole — it would be torn into subatomic particles by the gravitational stresses.)

blue stragglers: A hot, massive, bright blue star found in the core of some globular star clusters, formed by the head-on collision of two red giant stars.

blue variables: Also known as Luminescent Blue Variables, these are unstable, blue giant stars which are extremely massive and very short-lived.

Cepheid variable star: An unstable star whose brightness varies considerably over a relatively short period of time (days). These tend to be rather large stars whose surface can trap the star's internal energy output until it builds up to a point where it erupts in a potentially dangerous burst. A related object is a "flare star" which can increase in brightness for periods as short as minutes.

flares, solar: Sudden bursts of energy from the surface of a star. Usually associated with sunspots and prominences, they are often accompanied by powerful magnetic fields.

Lazarus star: A star that has exploded as a supernova, but somehow survives and expands into a second red giant phase, then collapses again and explodes as a second supernova. These stars are often in the center of several nested layers of gas, ejected from previous supernova explosions.

non-radial pulsators: A type of star with huge tidal waves of hot plasma racing across their surfaces, causing irregular pulsation below the surface.

pulsar: The dying embers of a large collapsed star. It rotates rapidly, sending a powerful jet of potentially dangerous radiation, thereby appearing to pulse at several times a second. Imagine a spinning searchlight, sending out a powerful beacon of radiation. (Voyager shields might not be able to protect the ship at a sufficiently close range.)

red giant star: A star which has become very bloated toward the end of its life. Some red giants are bright, some are dim, but all are relatively cool in temperature. Some red giants ultimately collapse and explode, becoming supernovas.

runaway star: A star which, due to gravitational oddities associated with its birth, is moving through the Milky Way Galaxy at relatively high (sublight) speeds.

shell star, B-type: An unstable star of spectral type B that sporadically puffs off shells of gas.

stellar fusion ignition: The birth of a star. As suggested above, it is possible for a nebula or other gas cloud to (over millions of years) coalesce into a swirling whirlpool. This can eventually condenses into a dense central object which can become hot enough to ignite into a new star. The leftover "debris" from such a star's formation can form planets. Although this process is extremely protracted, it is possible that our ship might arrive at such a gas cloud just in time to witness (and be threatened by) the star's birth.

supernova: A star near death, which has exhausted almost all of its nuclear fuel. Lacking the ability to sustain itself, it collapses, triggering one final massive explosion. A sufficiently large supernova could very easily wipe out any inhabited planets in a solar system. The x-rays from a supernova could even threaten life in a solar system several light-years away. If the star was massive enough to begin with, it could ultimately collapse into a black hole. Out of the ashes of the supernova explosion can come the heavier elements which form the building blocks of life. Many of the atoms in our bodies were formed billions of years ago in such an explosion.

white hole: A hypothetical entity, some kind of opposite of a black hole from which radiation and matter appear to originate from nothingness.