Tuesday, April 24, 2007

Star Birth In The Extreme

Mosaic of the Carina Nebula - Click Image to Enlarge

This immense nebula contains a dozen or more brilliant stars that are estimated to be at least 50 to 100 times the mass of our Sun. The most rich and extensive one is the variable star eta Carinae, seen at far left. Eta Carinae is in the final stages of its brief eruptive lifespan, as shown by two billowing lobes of gas and dust that foretell its upcoming explosion as a titanic supernova.

The fireworks in the Carina region started three million years ago when the nebula's first generation of newborn stars condensed and ignited in the middle of a huge cloud of cold molecular hydrogen. Radiation from these stars carved out an expanding bubble of hot gas - a cavity. The island-like clumps of dark clouds scattered across the nebula are nodules of dust and gas that have so far resisted being eaten away by photoionisation by the stellar radiation.

The hurricane-strength blast of stellar winds and blistering ultraviolet radiation within the cavity is now compressing the surrounding walls of cold hydrogen. This is triggering a second stage of new star formation.

Our Sun and Solar System may have been born inside such a cosmic furnace 4600 million years ago. In looking at the Carina Nebula we are seeing star formation as it commonly occurs along the dense spiral arms of a galaxy.

This immense nebula is an estimated 7500 light-years away in the southern constellation Carina, the Keel of the old southern constellation Argo Navis, the ship of Jason and the Argonauts from Greek mythology.

Credit: NASA, ESA, N. Smith (University of California, Berkeley),
and The Hubble Heritage Team (STScI/AURA)

The Carina Nebula: Star Birth in the Extreme from Hubblesite
Mapping The Invisible from Science Daily
Star-Forming Region in the Carina Nebula
Forming Galaxies Captured In The Young Universe

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