Flat disk of matter spiraling down onto the surface of a star or black hole.
Often, the matter originated on the surface of a companion star in a binary system.
A noticeable pattern of stars that makes up part or parts of a constellation. The most notable
is the "Big Dipper" which is part of Ursa Major and the "Teapot" which is part of Sagittarius.
Created in 1800 by Johann Schröeter, their primary purpose was to search for the hypothetical
planet, expected to orbit between Mars and Jupiter. Although they never located this
planet, they are accredited with the discovery of many minor planets. The group was disbanded
in 1815.
A star that varies in magnitude over a calculated period of time. These stars are used
to calculate the distances to other galaxies by comparing their absolute magnitudes and their
apparent magnitudes.
An incandescent, transparent layer of gas, mainly hydrogen, several thousand miles in depth, that lies
above and surrounds the photosphere of the sun but is distinctly separate from the corona.
A star, constellation or asterism that is close to the Pole Star that never appears to set. The
latitude of your location will determine what is circumpolar.
A celestial body that resembles a 'Dirty Snowball' that travels travels through the solar
system in a highly elliptical orbit. On close approach to the Sun, the Comet grows a tail by
spewing gases and material heated by the Sun.
A grouping of stars that make up patterns named for historical, mythological, or other figures
in the sky. The sky is divided up into 88 such constellations.
A sudden release of charged particles in plasma from the Sun. These releases emits radiation across
the spectrum from radio waves to X-rays and can wreak havoc to Earth's ionosphere causing
auroua's a couple days later.
A disk-shaped region beyond the orbit of Neptune, 30 to 100 AU from the Sun containing
millions of icy bodies. The Kuiper Belt is thought to be the source of many short term comets.
The speed necessary to maintain orbit, too slow means reentry into the atmosphere
and too fast means escape velocity and leaving the celestial body behind.
Jets of gas emanating from the Sun with a spiky and firey appearance that lasts for a few minutes and
are found in the lower chromosphere at the edges of granulation patterns.
The violently explosive death of a star, caused by the sudden onset of nuclear burning (type I), or an enormously
energetic shock wave (type II). It is one of the most energetic events of the universe, a supernova may
temporarily outshine the rest of the galaxy in which it resides.
An asteroid that follows the orbit of a planet at the leading and trailing
Legrange points (L4 and L5 respectively). These points are about 60 degrees
ahead of and behind the planet. Jupiter has more Trojans at its
leading Legrande point than at its trailing point. The other planets may
also have asteroids at their Lagrange points.
