An explosive event involved two protostars in the Orion Molecular Cloud 1

The explosion in the Orion Molecular Cloud 1  (Image ALMA (ESO/NAOJ/NRAO), J. Bally/H. Drass et al.)
The explosion in the Orion Molecular Cloud 1 (Image ALMA (ESO/NAOJ/NRAO), J. Bally/H. Drass et al.)

An article published in “Astrophysical Journal” describes a research about the birth of a group of massive stars in the Orion Molecular Cloud 1 (OMC-1). A team of astronomers led by John Bally of the University of Colorado used the ALMA radio telescope to see inside the cloud and detect the debris scattered by that really chaotic event.

The Orion Molecular Cloud 1 is about 1,350 light years from Earth and is one of the molecular clouds that are part of the Orion Nebula complex. Inside it there are the conditions for star formation, in fact there are many massive protostars and something violent happened because today we see its explosive consequences. Reconstructing the events accurately is perhaps impossible but the authors of this research estimated that the energy released is comparable to that emitted by the Sun in 10 million years.

According to the reconstruction, about a hundred thousand years ago several protostars formed and started moving following mutual gravitational influences. A few centuries ago two of these protostars grazed each other or even collided, triggering a powerful eruption that drove away other nearby protostars and giant filaments of gas and dust into interstellar space at speeds of over 150 kilometers per second.

John Bally and his team had detected traces of the debris in the Orion Molecular Cloud 1 in 2009 using the SMA radio telescope in Hawaii. Subsequently, they carried out further observations but this time at infrareds using the Gemini South telescope in Chile. In particular, they revealed the structure of the filaments, which have an extension of nearly a light-year from end to end.

The ALMA radio telescope, inaugurated in March 2013, is much more powerful and sensitive than SMA. The new observations with ALMA revealed important details about the distribution and the high-velocity movement of the carbon monoxide gas in the filaments.

This new phase of this event’s study is useful to better understand how it develops and what impact it can have on the star formation within a molecular cloud. That explosion devastated the cloud in which the stars were born so this kind of event can regulate the star formation pace in molecular clouds.

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