ALMA spies fireworks in Orion
The remnants of a collision between two infant stars has been captured by ALMA. The beautiful images could help astronomers understand how such stellar crashes govern the rate at which our Galaxy forms stars.
Stellar explosions are often associated with the death of stars in supernovae, but this blast was caused by two stars as they were being born.
Credit: ALMA (ESO/NAOJ/NRAO), J. Bally/H. Drass et al.
Fireworks nearby to Orion’s belt have been caught in unrivalled detail in the latest observations from the Atacama Large Millimeter/submillimetre Array (ALMA). The image reveals beautiful streams of gas erupting from a young stellar nursery following a collision between infant stars.
The display occurred in the Orion Molecular Cloud 1 (OMC-1), part of a complex of bright nebulae and gas clouds (including the Orion Nebula) 1,350 lightyears away that spans Orion’s belt to his sword. OMC-1 is a gas cloud with several hundred times more mass than the Sun. Around 100,000 years ago the cloud began to collapse under its own gravity, causing several infant protostars to ignite. In the close quarters of the cloud, they began a complex dance of gravitational interactions that caused two of them to clash together around 500 years ago.
The crash caused the stars to erupt, launching nearby stars out of the region and casting hundreds of gas and dust streamers into interstellar space at over 150 km/s. It’s uncertain if the stars collided head on, or merely grazed each other, but the interaction was still intense enough to release as much energy as the Sun does in 10 million years.
Read more about ALMA's observations of young stars in BBC Sky at Night Magazine
However, such cosmic fireworks are just as shortlived as their Earthly counterparts, lasting only a few centuries before fading.
Such collisions are relatively common, and appear to play an important role in maintaining the rate at which stars grow and form. When explosions like these occur they often destroy their parent cloud, preventing the birth of new stars.
The cloud was first imaged in 2009 by the Submillimeter Array in Hawaii, but these new ALMA images show the explosion in incredible high resolution. These observations will allow astronomers to understand the precise nature and power of the blast, and better interpret what effect such events could have on stars forming throughout the Galaxy.