An article published in the journal “Astronomy & Astrophysics” reports an overview of the results of the VISTA Star Formation Atlas (VISIONS) survey, which aimed to observe star formation regions visible from the southern hemisphere. A team of researchers assembled more than one million infrared images captured over five years by ESO’s VISTA telescope in Chile to create an atlas of five stellar nurseries in the cosmic neighborhood. This is one of the surveys focused on star formation processes with the aim of better understanding its various phases.
The clouds of gas and dust from which stars are born are also the ones that block many electromagnetic frequencies making it difficult to study the various stages that lead to star birth. Infrareds are among the electromagnetic frequencies that pass through those clouds and the VIRCAM (VISTA InfraRed CAMera) installed on the VISTA telescope is very useful to study stellar nurseries.
In the VISIONS survey, VIRCAM was used to observe star-forming regions in the constellations Orion, Ophiuchus, Chameleon, Corona Australis, and Lupus. They are all less than 1,500 light-years away from Earth and therefore in the cosmic neighborhood. They are also large areas and include tens of thousands of stars that are young from an astronomical point of view, ranging in age from 100,000 to 10 million years. During the survey, they were all observed twice a year in order to locate the stars in the midst of the clouds of gas and dust and to measure their movements.
All this information collected in the new cosmic atlas will help to better understand star formation processes. The models developed by astronomers over decades have become sophisticated but there are still many details to clarify. The questions also concern planets that can form together with stars, a subject on which new data continues to be collected practically every day.
There are also questions about what happens to newborn stars after their formation. Many stars can be born in a large cloud but how do they move? Normally, pairs or even multiple systems form, why do some stars end up not being gravitationally bound to others like the Sun? Tracking the movements of the young stars observed in the VISIONS survey offers new information in this regard as well.
This type of survey is also very useful as a foundation for follow-up studies in which data is used that can complement data collected with other instruments. For example, data on the movements of young stars tracked in the VISIONS survey can be combined with data included in sky maps created thanks to ESA’s Gaia space probe.
Surveys such as VISIONS remain useful for many years, in this case also providing data to find study objects to observe with instruments that will enter service in the next few years. The Extremely Large Telescope (ELT), ESO’s next-generation telescope currently under construction in Chile, will be able to provide greater detail of those star-forming areas.
