The opposite is true for Cyg OB2#9, which remains stable during its entire orbit. The delighted astrophysicist explains, “We can now consider this system as an archetype for the study of the characteristics of these stellar winds. It can serve as a kind of Rosetta stone. Now that we know all its properties we can use it as a reference model because what works for simple cases can also be applied to complex ones”!   

Although massive stars represent a relatively recent research discipline, the study of the stellar winds has become an important subject. “Even though massive stars are quite rare and last for “only” a few million years, they control everything. In order to understand the galaxy we need to understand them. It has been barely two or three years since we began to understand the way they are formed. Moreover, an understanding of the stellar winds is crucial because they have an impact on the stellar environment and they make the creation of new stars possible by ejecting matter. ” The stellar winds also “sculpt” the interstellar environment and enrich it with the heavy elements that are produced in the core of these luminous stars.  She continues, “These elements can contribute to life. This means that the elements that surround us were produced by giant stars and then “brought” to Earth. It takes three generations of giant stars to create a planet like the Earth. Giant stars synthesize complex atoms: carbon, oxygen, uranium etc. They even create iron in their cores (our sun contains carbon). Therefore they play a predominant role in this regard. ”

Too much fog

However, because massive stars are rare it is quite difficult to gather information about them. For example, for every star with a mass equivalent to between 60 and 120 times that of the sun there are 250 which have one or two times the mass of the sun and 5,600 which are known to have one-fifth or one-tenth the mass of the sun. Do you get the idea? “For the moment we know fewer than 10 000 which is very few. As for the rest, we can’t observe them as there is really too much fog in the galaxy”! This goes to prove that the data obtained by Yaël Nazé and her team is rare and precious.

Many technological advances will be necessary to design a telescope that is capable of penetrating this galactic fog so that new stars can be detected at greater distances. In the meantime, there remains a lot of work to be done before all the secrets of Cyg OB2#9 can be known. Research is continuing on the subject-the study of its radio waves is just finished and its interferometric study is still ongoing-the signals of several small telescopes are combined in order to determine its position, its size and distance etc. Its objective is to provide a seamless physical understanding of the system and complete our understanding of massive stars and their stellar winds. “And the last step will be to provide a model of the system”