Cosmic findings

Chilean telescope captures dramatic images of star birth

ALMA produces best images yet of a known star’s early formation, leading to an enhanced ability to study the behavior of stellar winds.

Friday, August 30, 2013 Category: Education
The stunning stellar outflows of Herbig-Haro 46/47, as imaged by ALMA. Photo by ESO. The stunning stellar outflows of Herbig-Haro 46/47, as imaged by ALMA. Photo by ESO.


Astronomers at the world’s largest ground-based observatory in Northern Chile have captured unprecedented images of a newborn star.

The star, Herbig-Haro 46/47, has been the subject of intrigue in the astronomy world for years, due to the vast, energetic clouds of material it continuously expels. Studying these outflows is a key component in understanding how stars form, yet detailed information about how they behave in the case of Herbig-Haro 46/47 has remained elusive — until now.

Formerly, massive amounts of dust prevented a sharp picture of the star — now, using the world class technology and unrivalled sensitivity of the Atacama Large Millimeter/submillimeter Array (ALMA), scientists were able to produce images with minimal interference. To the astronomers on the study, the most immediately obvious discovery was that the outflows are far more energetic and travel with far greater momentum than previously thought.

"ALMA's exquisite sensitivity allows the detection of previously unseen features in this source, like this very fast outflow,” Héctor Arce of Yale University, the lead author of the study, said. “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."

As well as the enhanced clarity, ALMA was also able to produce the images in under five hours — ten times faster than the other existing technology performing a similar study. These images were also taken when ALMA was still under construction, and operating at a fraction of its potential power.

"The detail in the Herbig-Haro 46/47 images is stunning,” Stuartt Corder, of ALMA and joint author of the study, said. “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."

The team also discovered an unsuspected outflow that seems to be coming from a lower mass companion to the young star. This secondary outflow is apparently carving its own hole out of the surrounding cloud.

"This system is similar to most isolated low mass stars during their formation and birth,” Diego Mardones of the Universidad de Chile and co-author on the study, said. “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."

Due to its almost non-existent humidity and clear skies, the Atacama is the world’s premier location for astronomy. Chile is home to almost half the world’s telescope infrastructure, and this is set to increase to over two thirds in the next decade.