Free Astronomy Magazine May-June 2025

9 MAY-JUNE 2025 ASTRO PUBLISHING Compared to our Sun, which at about 4.6 billion years old is in a stable phase of its life, the stars in RCW 38 are still very young. At less than a million years old, RCW 38 contains some 2000 stars, creating this psychedelic landscape. This young star cluster is bustling with activity, which makes it an in- teresting target for astronomers to observe. Star clusters are like giant pressure cookers, containing all the T his is an 80-million-pixel picture of the star cluster RCW 38, lo- cated 5500 light-years away in the constellation Vela. RCW 38 is a young cluster containing about 2000 stars, and is bursting with star-form- ing activity. [ESO/VVVX survey] ingredients for star formation: dense gas clouds and opaque clumps of cosmic dust. When this mixture of gas and dust collapses under its own gravity, a star is born. The strong radiation coming from these newborn stars makes the gas that encompasses the star cluster glow brightly, creating the pink hues we see here in RCW 38. It’s truly a spectacular sight! Yet in visible light many stars in the RCW 38 cluster re- main hidden from us, because dust blocks our view of them. That is where the VISTA telescope, at ESO’s Paranal Observatory, comes in: its VIRCAM camera observes in- frared light which, unlike visible light, can go through dust almost unimpeded, revealing the true riches of RCW 38. Suddenly, we also see young stars within dusty co- coons, or cold ‘failed’ stars known as brown dwarfs. This infrared image was taken during the VISTA Vari- ables in the Vía Láctea (VVV) survey, which has produced the most de- tailed infrared map of our home galaxy ever made. Surveys like this reveal as yet un- known astronomical objects, or give us a new view of known ones. Since this image was taken, VISTA’s faithful VIRCAM camera, which has conducted numerous imaging sur- veys since 2008, has retired after an impressive run. Later this year, the telescope will receive a brand new instrument called 4MOST, which will gather the spectra of 2400 ob- jects at once over a large area of the sky. As VISTA is born again, the future looks bright. !