Large & Small Magellanic Clouds

The Large & Small Magellanic Clouds – www.eso.org/public/images/b01/

The Large Magellanic cloud is a nearby galaxy once considered to be an irregular type until astronomers studied it more closely. It now turns out to be an irregular with a bar across its heart. It may once have been a spiral. The LMC (as it is known) is visible in Earth’s Southern Hemisphere skies, along with its companion dwarf galaxy, the Small Magellanic Cloud (SMC). The Milky Way is consuming gas that is flowing from the Magellanic clouds (in the Magellanic Stream). Eventually these two smaller galaxies might collide with the Milky Way. Both the LMC and the SMC have star-forming regions, and the LMC was the site of the spectacular 1987a supernova explosion.

Large Magellanic Cloud Profile

Designation:LMC
Type:Disrupted Barred Spiral
Diameter:14,000 ly
Distance:163,000 ly
Mass:10 billion M☉
Number of Stars:30 billion
Constellation:Dorado & Mensa
Group:Local Group

Small Magellanic Cloud Profile

Designation:SMC
Type:Dwarf Galaxy
Diameter:7,000 ly
Distance:197,000 ly
Mass:6.5 billion M☉
Number of Stars:3 billion
Constellation:Tucana & Hydrus
Group:Local Group

Facts about the Magellanic Clouds

  • The Large Magellanic Cloud lies about 163 thousand light-years from Earth. Its companion, the Small Magellanic Cloud is about 200,000 light-years away.
  • For many years astronomers thought the Magellanic Clouds orbited the Milky Way. Recent measurements may prove that they could be moving too fast for that.
  • The Magellanic Clouds are gas-rich, meaning they have a higher portion of their mass as gas. They also have less portion of their mass bound up in metallic elements.
  • The Magellanic Clouds have both had their shapes distorted by gravitational interactions with the Milky Way. As these galaxies pass near the Milky Way, their gravitational pull also misshapes the outer bars of our galaxy.
  • Recent studies of the Small Magellanic Cloud indicate that it might be a former single galaxy split into two remnants. Gravitational interactions with the LMC may have broken that galaxy apart.
  • The Large Magellanic Cloud contains a highly active starbirth region called the Tarantula Nebula. It is part of a larger cloud of gas and dust, and its high rate of star formation may be caused by compression of interstellar gas and dust by the collision of the cloud with the interstellar medium. The 1987a supernova exploded not far from this region.