Two blue stars glow brightly as they rip apart a dark cloud in the constellation of Orion. This might sound like the start of a sci-fi novel, but it’s actually a description of the latest image release from the European Southern Observatory’s (ESO) VISTA survey.
The telescope snapped an incredible image of Messier 78, a well-known reflection nebula 1,600 light-years from Earth. The image shows two blue supergiant stars called HD 38563A and HD 38563B as they emerge from the dark cloud that birthed them.
The cloud itself is about 5 light-years across and has been carved by the powerful light of the stars. It is surrounded by three other nebulae that have the catchy names of NGC 2064, NGC 2067, and NGC 2071. Together, the system contains 45 T Tauri, a special class of variable stars.
T Tauri stars are very young objects, still undergoing the processes that will lead to them becoming fully-fledged stars. They appear very bright, festooning the nebulae in red and yellow, but they are still not hot enough to initiate nuclear fusion at their core. It takes several tens of millions of years for stars to go from dense clumps of gas to the brilliant objects we all know and love.
Messier 78, which was first discovered in 1780, also has 17 Herbig-Haro objects. These are narrow jets of gas and dust created by newly born stars as they interact with the stellar cloud that formed them. It is very interesting to see so many of them here, as they are very short-lived events in cosmic terms, lasting for only a few thousand years.
If we could wind back time and look at our own Sun 5 billion years ago, we would see that it was born in a gas cloud not too dissimilar from this one. The life and death of stars is linked in these clouds. They are formed by supernovae and allow for a new generation of stars. This process is what drives the heavy elements’ enrichment of the universe, and from those elements planets, asteroids, and comets form, as well as all of us.