User:Rursus/Large Magellanic Cloud

(Place for a rework of Large Magellanic Cloud ― please regard this page as an article space, where mistakes and sketches are allowed. Discuss on the talk page.)

(intro)

New sources found, dot points

 * Supernova SN1987A happened in the LMC
 * first supernova for almost 400 years to be visible to the naked eye


 * LMC is a dwarf irregular galaxy
 * 20,000 light-years across
 * 4th largest member of the Local Group
 * Named after Ferdinand Magellan, who noted it in 1519
 * Contains, among other things:
 * diverse population of young stars
 * HII regions
 * 30 Doradus
 * indications of encounters with the Milky Way such as warps, rings and tidal distortions


 * LMC probably contains dark matter
 * Flat rotation curve
 * LMC is "disorganized and messy"
 * Rotation is disturbed
 * Contained within the dark matter halo of the Milky Way


 * Lies in Dorado and Mensa
 * Visible as a large hazy region in the southern sky
 * Due to its proximity, a better study can be made of its interior than any other galaxy outside our own
 * Contains open clusters and globular clusters


 * Contains a small, off-center, bar
 * Prominent northern arm
 * Two small southern arms
 * Prevailing view before 1950 was that LMC is irregular
 * Gerard de Vaucouleurs demonstrated spiral nature with photographic plates he recorded from 1952–1955
 * H C Russell claimed spiral structure in 1890


 * Easily visible to the naked eye
 * Receding from the Milky Way
 * Contains one twentieth as many stars as MW
 * Analogous to our galaxy in many ways
 * Easy to study because it is obvious where the components are relative to each other
 * Bar consists mostly of old stars, but some young ones are present


 * Receding at 276 km/s


 * The spiral arms comprise the Pop I stars
 * The bar consists of low mas Pop II stars
 * Between 5% and 9% of the LMC is composed of atomic hydrogen
 * Lies 30° out of the galactic plane
 * Reduces absorption by Galactic gas


 * Inclined 34.7° +- 6.2°
 * Disk may be warped
 * Line of nodes 122.5° +- 8.3°
 * Important in determining the cosmological distance scale
 * Used to study the presence of dark objects in the Milky Way's halo through microlensing

Images

 * NasaImages.org: Our Chaotic Neighbor/LMC, LMC portrait in IR.