Astronomy

Astronomy/Variable_Stars Variable Stars



Galaxies
A galaxy is a gravitationally bound group of stars, dust and stellar remnants. In Astronomy, you will be tested over your knowledge of galaxies, various DSOs (deep sky objects), and mathematical relationships.

This year's galaxies fall into two categories: normal galaxies, and starburst galaxies.

Normal Galaxies
Normal galaxies are classified by the Hubble system as being either elliptical or spiral. Elliptical Galaxies are generally older and larger than spiral galaxies. Spiral galaxies consist of an inner core of old stars moving slowly and outer arms of faster-moving younger stars. They also have a separate classification, as some spirals are barred, or they have a horizontal bar of stars protruding out from the galactic core. The normal galaxies include the Milky Way Galaxy, the Andromeda Galaxy and the Triangulum Galaxy.

Starburst Galaxies
Starburst galaxies are typified by significantly greater levels of star formation than normal galaxies. They are often normal galaxies that have collided with each other, causing gravity ripples and star formation. The starburst galaxies in this year's DSOs include M82, M84, M101, the Cartwheel Galaxy, and C153.

Deep Space Objects
Although the focus of this year's event is galaxies, many of the DSOs are other stellar objects including: M15 the globular cluster, Sag A* the black hole, Epsilon Aurigae the eclipsing binary, G1 (Mayall II) the globular cluster, NGC 604 the stellar nursery, and M33 x-7 the x-ray binary. Most of these are prominent objects located in the other galaxies studied.

This Year's DSO's

 * Epsilon Aurigae**
 * AAVSO: Epsilon Aurigae
 * Milky Way Galaxy
 * NASA: Our Milky Way Gets a Makeover
 * Sagittarius A*
 * Chandra Photo Album: Sagittarius A*: 06 Jan 03
 * Andromeda Galaxy (M31)
 * NASA APOD: November 14, 1999 - M31: the Andromeda Galaxy
 * Cartwheel Galaxy
 * Chandra Photo Album: Cartwheel Galaxy: 11 Jan 06

-**is part of a special viewing campaign this year and will be included up to at least 2011.

This year's topic is centered around quasars, AGNs (active galactic nucleus), galaxy clusters, and groups of galaxies.

This Year's DSOs (2010-2011)
-**Epsilon Aurigae is part of a special observing campaign through 2011 and will also be included in the DSO list for the 2011/2012 season.
 * Epsilon Aurigae**
 * AAVSO: Epsilon Aurigae
 * NGC 6240
 * 3C321
 * Cen A
 * Stephan's Quintet
 * MACSJ0717.5+3745
 * Bullet Cluster (1E 0657-56)
 * Perseus A (NGC 1275)
 * SN 2006gy
 * SN 1996cr
 * NGC 4603
 * NGC 7771
 * NGC 2623
 * JKCS041
 * NGC 1068
 * H2356-309

Other Information
Although these topics are the focus of this year's competition, there are other topics which you will need to be familiar with.

Stellar Life Cycle
The life cycle differs between stars depending on their mass. Normal-mass stars begin in stellar nurseries, and some matter condenses to create a protostar. This gains more mass until fusion begins, when it becomes a main-sequence star. Then, as it uses up its store of energy, it grows to be a giant star by the end of its lifetime. Once it uses its entire store, it collapses into a planetary nebula and later a white dwarf. Larger stars are similar, except they begin with more mass and grow to supergiants. At the end of their lifetime, they can explode in a massive explosion known as a supernova and/or collapse into a neutron star or a black dwarf.

The Competition
The competition usually consists of a test, which may contain stations or not. Each team member can bring a laptop or a binder to put their information in, so bring as much as you may need, as there is a wide variety that can be asked. The test usually has many questions regarding mathematical computations, so it is important to have a calculator and a formula sheet ready.

Useful Resources

 * American Association of Variable Star Observers
 * [[Media:Formula Sheet.pdf|Formula Sheet for Math Portion of Astronomy]] for the mathematical section
 * Reach for the Stars for some sample pictures
 * Scioly Test Exchange