An article published in the journal “Nature Astronomy” describes a study of the IRAS 04191+1523 system, consisting of two low-mass newborn stars. A team of astronomers led by Jeong-Eun Lee of Kyung Hee University, Korea, used the ALMA radio telescope to figure out how pairs of little stars form. The discovery that the two stars’ rotation axes are misaligned led them to conclude that a turbulence caused the fragmentation of the gas cloud from which they were born.

In recent years, various team of researchers tried to find out the mechanisms of formation of star pairs since they are the most common case. Just a few weeks ago, the results of one of these researches that concerned small-mass stars, comparable to the Sun, were published.

Other researches also showed that there are differences depending on whether the stars are close or far away. In October 2016, the results of a research based on the use of ALMA and VLA were published to observe the system called L1448 IRS3B, where a dust and gas disk is fragmenting into a multiple star system, were published.

Now another research has focused on the IRAS 04191+1523 system, composed of two really small stars, with masses that are only a tenth of the Sun’s. The distance between the two stars is about 30 times that between Neptune and the Sun so it’s definitely an example of the case called wide binaries. Their age is estimated at less than half a million years so from an astronomical point of view they’re very young and represent an excellent target for this kind of research.

The researchers used the ALMA (Atacama Large Millimeter/submillimeter Array) radio telescope, inaugurated in March 2013, because its high resolution made it possible to capture images that show the rotation of the gas disks surrounding the two stars of IRAS 04191+1523. In particular they analyzed the signal from the carbon monoxide molecules to understand their motion and thanks to those images they could see that the rotation axes of the two stars are misaligned.

This system is too young to have had interactions with external objects massive enough to influence the two stars without being visible. The conclusion is that the system was formed in such a way by a turbulent fragmentation of a gas and dust cloud and not by a disk fragmentation and subsequent migration. In the latter case, the rotational moment of the gas would align the two stars’ axes.

Thanks to very powerful instruments such as ALMA, in recent years researchers are making leaps forward in understanding star-forming mechanisms. Very young systems such as IRAS 04191+1523 can be studied in details unthinkable until a few years ago, allowing astronomers to study these cosmic events and greatly improve the existing models.