August 20, 2013
ALMA Snaps Images Of Dramatic Star Birth
Lee Rannals for redOrbit.com - Your Universe Online
Astronomers say they have obtained a close-up view of material streaming away from a newborn star. Using the Atacama Large Millimeter/submillimeter Array (ALMA) telescope, a team of scientists was able to discover the jets coming off an object called Herbig-Haro 46/47 are even more energetic than previously believed. The new images also reveal a previously unknown jet pointing in an entirely different direction.
The new images reveal detail in two jets, one coming towards Earth and one moving away from it. The jet moving away was almost invisible in earlier pictures made in visible light because of obscuration by the dust clouds surrounding the new-born star.
These new observations revealed some of the ejected material had velocities higher than previously measured, meaning the outflow gas carries more energy and momentum than scientists originally believed.
"ALMA's exquisite sensitivity allows the detection of previously unseen features in this source, like this very fast outflow," said Héctor Arce of Yale University, who is first author of the paper published The Astrophysical Journal. "It also seems to be a textbook example of a simple model where the molecular outflow is generated by a wide-angle wind from the young star."
The team obtained the observations of Herbig-Haro 46/47 in just five hours using ALMA. Similar quality observations with other telescopes would have taken up to ten times longer.
"The detail in the Herbig-Haro 46/47 images is stunning. Perhaps more stunning is the fact that, for these types of observations, we really are still in the early days. In the future ALMA will provide even better images than this in a fraction of the time," said Stuartt Corder, a co-author of the new paper from Joint ALMA Observatory in Chile."
Young stars are violent objects that can eject material at very high speeds. Once this material crashes into the surrounding gas, it creates an object like Herbig-Haro. This particular object sits about 1,400 light-years away from Earth in the southern constellation of Vela.
"This system is similar to most isolated low mass stars during their formation and birth," Diego Mardones of the Universidad de Chile and another co-author of the study. "But it is also unusual because the outflow impacts the cloud directly on one side of the young star and escapes out of the cloud on the other. This makes it an excellent system for studying the impact of the stellar winds on the parent cloud from which the young star is formed."
Arce credits ALMA for making the observations possible, saying this shows "there will certainly be many surprises and fascinating discoveries to be made with the full array."