Seeing stars: largest ever observed in the Milky Way

A team led by Dr Nicolas Peretto from Cardiff University and CEA/AIM Paris-Saclay, France has been able to observe the formation of a monster star, the largest ever seen within the Milky Way.

Within a dark cloud stellar womb 500 times the mass of the Sun, the star is currently in the process of forming and it's still growing steadily, hungrily feeding on the material racing towards it. The cloud is expected to give birth to a brilliant and bright star, which itself could be up to 100 times the mass of the Sun.

The observations were made using the Atacama Large Millimeter/submillimeter array (ALMA), a collection of radio telescopes in the Atacama desert of Northern Chile.

The whole process of the birth of these stars remains shrouded in mystery, however the astronomers were able to use ALMA almost as a prenatal scan to get a clearer look at the formation of this monster star. The star is located 11,000 light years away in a cloud known as the Spitzer Dark Cloud and the team were able to look in detail at both the amount of dust and the motion of the gas moving around within — revealing the mammoth star in all its glory.

Dr Peretto from the School of Physics and Astronomy said: "These results are very exciting in many ways. First, even though we already knew that the cloud under investigation was a good candidate for being a massive-star-forming cloud, we were not expecting to find such a massive star progenitor at its centre. This object can potentially form a star which is 50 to 100 times more massive than the Sun. Only ~0.01% of all stars in the Galaxy are expected to reach that kind of mass! This is a very exciting time for radioastronomy. "

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