A team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) has captured a beautiful close-up view of an object named Herbig-Haro 46/47.
This image of Herbig-Haro object HH 46/47 combines radio observations with ALMA with visible light observations from the New Technology Telescope. The ALMA observations, orange and green, lower right, of the newborn star reveal a large energetic jet moving away from us, which in the visible is hidden by dust and gas. To the left, in pink and purple, the visible part of the jet is seen, streaming partly towards us. Credit: ESO /ALMA / NAOJ / NRAO / H. Arce. Acknowledgements: Bo Reipurth.
Young stars are violent objects that eject material at speeds as high as 1 million km per hour. When this material crashes into the surrounding gas it glows, creating a Herbig-Haro object.
Herbig-Haro 46/47 is located in the southern constellation of Vela about 1,400 light-years from us.
The new observations of Herbig-Haro 46/47 revealed two jets – one coming towards Earth and one moving away. The receding jet was almost invisible in earlier pictures made in visible light, due to obscuration by the dust clouds surrounding the new-born star. Some of the ejected material had velocities much higher than had been measured before. This means the outflowing gas carries much more energy and momentum than previously thought.
“ALMA’s exquisite sensitivity allows the detection of previously unseen features in this source, like this very fast outflow. 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,” said Dr Héctor Arce of Yale University, who is a lead author of a paper published in the Astrophysical Journal (arXiv.org).
“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,” added co-author Dr Stuartt Corder of the Joint ALMA Observatory, Chile.
Co-author Dr Diego Mardones from the Universidad de Chile said that this system is similar to most isolated low mass stars during their formation and birth. 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.
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Bibliographic information: Héctor G. Arce et al. 2013. ALMA Observations of the HH 46/47 Molecular Outflow. ApJ 774, 39; doi: 10.1088/0004-637X/774/1/39
