An article published in the journal “Monthly Notices of the Royal Astronomical Society” reports a study of the galaxy NGC 1386 that shows that star formation processes are taking place in its central regions despite the fact that it contains mostly old stars. A team of researchers led by astronomer Almudena Prieto of the Instituto de Astrofísica de Canarias in Spain combined observations conducted in visible light and near-infrared with ESO’s VST and in radio waves with the ALMA radio telescope to study those processes that are bringing about a sort of rejuvenation within NGC 1386.
In the image (ESO/ALMA (ESO/NAOJ/NRAO)/A. Prieto et al./Fornax Deep Survey), a blue ring in the central phase of the galaxy NGC 138 shows star clusters that are very young in astronomical terms. In what appears almost like a golden outer ring are clouds of gas in which more stars will form.
About 53 million light-years from Earth, NGC 138 is a so-called Seyfert galaxy, a class marked by the presence of an active galactic nucleus that generates powerful electromagnetic emissions. Due to its shape, it’s classified as both a spiral galaxy and a lenticular galaxy. It contains mostly old stars but new stars are forming inside it.
This new study of the galaxy NGC 138 concerned the processes that led to the formation of new star clusters in its central regions, around the galactic nucleus. The VST (VLT Survey Telescope) at the Paranal Observatory in Chile made it possible to observe in visible light and in the near-infrared those clusters that are estimated to be around four million years old, very young in astronomical terms. This is the first observation of such a large simultaneous star formation in a galaxy that contains mostly old stars.
The same study showed the presence in a quasi-ring structure further outside the young star clusters of gas clouds from which other stars can be born. In this case, star formation has yet to begin and it will take a few million years before the results can be seen in new light on Earth.
The galaxy NGC 1386 has an active galactic nucleus, which means that at its center there’s a supermassive black hole surrounded by materials that are being heated significantly by gravitational interactions. Astronomers are studying the effects of these extreme objects on the galaxies that host them. In the case of NGC 1386, there may be a link between that activity and the star formation that is somehow rejuvenating the galaxy. These are all reasons why it will continue to be studied.
