A star’s mass shapes everything about its life, from how bright it shines to how it eventually dies.
Small stars like our Sun burn slowly for billions of years, while very massive stars live fast and end in powerful explosions called supernovae.
Mass also determines what elements stars create—such as carbon, oxygen, and iron—which later become the building blocks of planets and even life itself.
Despite its importance, measuring the mass of very young stars has always been a challenge, because they are often hidden inside thick clouds of gas and dust.
Now, astronomers are making major progress in solving this problem by studying young stars in the Orion star-forming region.
Orion is one of the closest and most active places in our galaxy where new stars are being born.
Using a powerful network of radio telescopes called the Very Long Baseline Array (VLBA), scientists are able to see through the dust and measure stellar masses with remarkable precision.
The VLBA is not just a single telescope. It is a system of antennas spread across the United States, from Hawaii to the Virgin Islands, all working together as one giant instrument. By combining signals from these widely separated antennas, astronomers can achieve extremely sharp vision—far better than any single telescope alone.
This allows them to detect tiny movements in stars that would otherwise be impossible to see.
To measure mass, researchers focus on binary stars—pairs of stars that orbit each other, like dancers spinning around a shared center.
By carefully tracking their motion over time, scientists can calculate how much mass each star must have to produce that motion. This method is powerful because it does not rely on theoretical models; instead, it is based directly on what astronomers observe.
Observing young stars is especially difficult because dust blocks visible and even infrared light. However, radio waves can pass through this dust, allowing the VLBA to see what other telescopes cannot.
The system is so precise that it can detect movements as small as the width of a human hair seen from thousands of kilometers away. By observing these tiny shifts over months and years, astronomers can map out the stars’ orbits and determine their masses accurately.
When the new measurements were compared with existing models of how young stars evolve, the results were mixed.
Some stars matched predictions well, but others did not, suggesting that current models may still need improvement. The observations also revealed hidden companion stars and showed that strong magnetic activity can exist even in relatively massive young stars.
These findings are important because young stars in Orion are similar to what our own Solar System may have looked like billions of years ago.
With these more precise measurements, Orion is becoming a kind of natural laboratory where scientists can test their ideas about how stars and planetary systems form.
Step by step, astronomers are getting closer to understanding how stellar neighborhoods like our own come into existence.
