Massive stars and their dead brethren are
teaming up to build a colossal space bubble outside our Milky Way galaxy.
Expanding envelopes
of gas and dust shed by massive stars and supernovas are in the act of
merging in a peculiar region of the Small
Magellanic Cloud, one of two dwarf galaxies
near the Milky Way.
"We are
witnessing the birth of a superbubble," said Rosa Williams, an astronomer at the
University of Illinois at Urbana-Champaign, in a statement.
The
superbubble spied by Williams and her colleagues is coming together in a region
of the Small Magellanic Cloud known as LHa115-N19 (N19), an area rich with
ionized hydrogen gas and populated by massive stars blowing out their own dust
and gas in stellar winds [image].
Supernova remnants, vast gas shells belched out during a star's explosive
demise, also appear in the region, researchers said [image].
"In N19, we
have not one star, but a number of massive stars blowing bubbles and we have
several supernova remnants," Williams said, adding that the shells and cavities
carved the objects may overlap. "Eventually, these bubbles could merge into one
enormous cavity, called a superbubble."
Williams
led the superbubble study and presented her team's findings this week at a Seattle
meeting of the American Astronomical Society. The astronomers relied on X-ray data
from the Chandra X-ray Observatory, as well as optical and spectroscopic
measurements to identify their superbubble-in-the-making.
"We caught
this particular region of N19 at a neat moment in time," Williams said. "The
stars are just dispersed enough that their stellar winds and supernova blasts
are working together, but have not yet carved out a full cavity."
The cosmic
formation not only gives astronomers a deeper glimpse into the lifecycles of
massive stars, but may also prove fruitful for planetary formation research.
During their lifecycles, massive stars generate - and ultimately distribute via
supernova - the heavy elements that are crucial for the formation of planets, researchers said.
"Our own solar system may have formed
within the confines of a superbubble," Williams said.
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