Stars not only die in spectacular explosions, sometimes they also form in spectacular outbursts. Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have been able to capture in high resolution the fireworks that accompany the birth of new stars.
Researchers used the observatory to look at the Orion Molecular Cloud 1 (OMC-1), a notorious star-forming region within the Orion Nebula that's located 1,300 light-years from Earth. About 500 years ago in the OMC-1, two of these protostars interacted – and we can now see the result.
Astronomers are not sure if the interaction was a near miss or a full-on collision, but whatever it was, it triggered a powerful eruption that propelled gas, dust, and many other protostars to a speed of up 150 kilometers (slightly less than 100 miles) per second. The Sun would have to shine for 10 million years to emit the same amount of energy that was released in the interaction.
The two protostars involved in the eruption have also been moving. Observations suggest that one is moving at 29 kilometers (18 miles) per second and the other at 13 kilometers (8 miles) per second. They were seen moving in opposite directions from the center of the explosion, which makes them the most likely guilty party in this event.
The study, published in The Astrophysical Journal, focused on the distribution and motion of carbon monoxide, which is a good tracer of how the material is being pushed out. Astronomers were able to use these molecules to work out how quickly the gas was leaving the molecular cloud and how long ago the explosion happened.
Stellar fireworks were first spotted in the OMC-1 in 2009, and since then they have been observed with several different instruments. These latest observations will provide much-needed data on these mysterious processes, with the explosion seen here believed to be an ephemeral event that lasted only a few centuries.
They might be quick in cosmic terms, but they could be fairly common. The protostars in this cloud are believed to have formed just over 100,000 years ago. It's possible a few hundred of these explosions could push enough gas out to stop star-forming clouds from creating stars.
ALMA and VLT views of an explosion in Orion. ALMA (ESO/NAOJ/NRAO), J. Bally/H. Drass et al.