Among many of the snapshots it has collected, a specific set of pictures from the Hubble telescope taken over a span of 14 years has allowed a team of scientists, led by Patrick Hartigan of Rice University, to get an extraordinary view of a star's birth. Pieced together, these images allowed scientists to view this particular event surrounding the formation of a new star, a magnificent stellar display, as a time-lapse movie. Their work is published in the July 20 issue of The Astrophysical Journal.
The most pronounced feature of these new stars is their jets of gaseous materials, called Herbig-Haro objects, flying out at speeds of 440,000 miles per hour. These objects were first studied in the 1950s by George Herbig and Guillermo Haro, the namesake for these jets, and only appear for 100,000 years of the star's lifespan.
New stars amass from the coalescing of cold hydrogen gas in substantial amounts, leading to a cascade of reactions and massive burst of energy, such as these awe-inspiring jets. The jets themselves appear when cosmic dust and other materials surrounding the new star fall in and get swallowed, then ejected away from the star.
The star's massive gravity attracts plenty of matter, organizing the matter in a disk orbiting the star, feeding some of the matter that fuels these jets. Later on in the lifespan of the star, the matter within the disk eventually leads to the formation of planets. However, the exact purpose of Herbig-Haro objects remains unclear, and their small lifespan greatly limits their presence in the night sky for astronomers to observe.
Altogether, Hartigan and his team have observed three stars that are producing these jets, all of which are roughly 1,400 light years away from Earth. These jets extend a distance of roughly ten times the width of our solar system, with their paths constrained to a certain extent by the magnetic field of their stars. Two of the stars observed are located just outside of the Orion nebula, while the third resides in the constellation Vela.
Having the ability to observe these jets over a period of time allows scientists to examine some more intricate properties of the jets' movements. A major aspect of these jets is that they do not leave the star as a smooth stream, but rather in clumps that can travel at different speeds. Often the slower movement of one clump will interfere with the movement of other clumps traveling along the same path, much like cars rear-ending each other on a highway.
The finer details about their movements and the fluid dynamics involved are rather complex, with Hartigan consulti ng colleagues at various institutions for their insight. This work has spawned interest in the way Herbig-Haro objects may interact with their environment, with experiments set to be conducted at the Omega Laser facility in Rochester, NY.
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