An international team led by Takeshi Sakai of the University of Electro-Communication, Japan, used the ALMA (Atacama Large Millimeter/submillimeter Array) radiotelescope to study a newborn star. Known only as G34.43+00.24 MM3 or more simply as MM3, this star is so young that it’s still surrounded by a huge cocoon of gas, a cloud about ten times larger than any other observed around stars of solar mass.

Stars are born in clouds of gas and dust that are very cold, at temperatures just above 10 Kelvin, which means a little more than 10 degrees above absolute zero. Infrared Dark Clouds (IRDCs) are dense regions with nebulae of that kind where star clusters are formed. Given that most stars are born in stellar clusters, investigating IRDCs has a key role in understanding the process of star formation.

A newly born star is surrounded by its native cloud of gas and dust, which is heated from its center. The temperatures are still cold, up to -160 degrees Celsius, which, however, are about 100 degrees higher than the temperature of the original cloud. For this reason, astronomers call these clouds “hot cores”. Commonly, they contain complex molecules, also organic ones such as methanol, ethyl cyanide and methyl formate.

Thanks to ALMA’s sensitivity, it was possible to observe MM3, an object that emitted a strong spectral line that corresponds to methanol that according to this research has a temperature of about -140 degrees Celsius. This is a strong indication of a star being born surrounded by its hot core. The size of this core is extraordinary: its length is about 800 times the distance between Earth and the Sun while its width is about 300 times the distance between Earth and the Sun.

The team also observed radio emission from carbon sulphide and silicon monoxide that reveal the detailed structure of the molecule flow emitted from the newly born star. The speed of the released gases is about 28 km/s (a little more than 17 mps) and its extent is about 4,400 times the distance of the Earth from the Sun. These values ​​have allowed to calculate that the age of the flow is just 740 years. These flows are common around young protostars but one like that of MM3 is rare.

The observations made with ALMA revealed a very young protostar with a huge hot core. It’s possible that there’s a very high mass of materials that fall faster than expected toward the core. It’s also possible that the core contains more than one protostar. This is one of the cases in which the completion of ALMA’s array of antennas will allow better observations to solve the mystery of MM3.

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