ALMA/NTT view of the Herbig-Haro object HH 46/47

Image credit and caption: ESO/ALMA (ESO/NAOJ/NRAO)/H. Arce. Acknowledgements: Bo Reipurth. This unprecedented image of Herbig-Haro object HH 46/47 combines radio observations acquired with the Atacama Large Millimeter/submillimeter Array (ALMA) with much shorter wavelength visible light observations from ESO’s New Technology Telescope (NTT). 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.

ALMA Takes Close Look at Drama of Starbirth:

Young stars are violent objects that eject material at speeds as high as one million kilometres per hour. When this material crashes into the surrounding gas it glows, creating a Herbig-Haro object. A spectacular example is named Herbig-Haro 46/47 and is situated about 1400 light-years from Earth in the southern constellation of Vela (The Sails). This object was the target of a study using ALMA during the Early Science phase, whilst the telescope was still under construction and well before the array was completed.

The new images reveal fine detail in 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. ALMA has not only provided much sharper images than earlier facilities but also allowed astronomers to measure how fast the glowing material is moving through space.


Isolated planetary-mass objects: “free-floating” planets do now appear to form in nature by the same process which forms stars. Previous research has shown that there may be as many as 200 billion free-floating planets in our galaxy, the Milky Way. Until now scientists have believed that such “rogue planets”, which don’t orbit around a star, must have been ejected from existing planetary systems. New observations of tiny dark clouds in space point out another possibility: that some free-floating planets formed on their own. A team of astronomers from Sweden and Finland used several telescopes to observe the Rosette Nebula, a huge cloud of gas and dust 4,600 light years from Earth in the constellation Monoceros (the Unicorn).

The paper of this research is now published; I have linked the preprint in an earlier post. The paper is “Mass and motion of globulettes in the Rosette Nebula”, G.F. Gahm et al., A&A, 555, A57 (2013).


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