The star\u2019s life, from its luminescence to death, depends on the stellar mass. The star\u2019s mass also tells about the presence of heavy elements such as carbon, oxygen, and iron. It also has a significant impact on the planet formation around them.<\/p>\n
However, determining the precise masses of young stars obscured by dust<\/a> has been challenging. Thanks to new radio measurements, astronomers can now solve the mass mystery of young stars in the Orion star-forming complex.<\/p>\n The Orion molecular complex, about 400 parsecs away, is a rich region for studying star formation. It includes well\u2011known areas like the Orion Nebula Cluster (ONC) and NGC 2024. This complex hosts hundreds of young stars that emit radio signals, spanning a wide range of masses and evolutionary stages. Because of this variety, it\u2019s an ideal place to explore how stars form in multiples and how that changes with their mass and age.<\/p>\n Astronomers used the U.S. National Science Foundation Very Long Baseline Array (NSF VLBA) to track the orbital motions of a sample of young binary star systems in Orion. By watching these \u201cdances\u201d with extraordinary precision at radio wavelengths, they were able to evaluate the stars\u2019 true masses without relying on theoretical models.<\/p>\n Lifting the veil on star formation in the\u00a0Orion Nebula<\/a><\/p>\n Young stars in Orion are hidden inside thick clouds of gas and dust, which block visible and even infrared light from most telescopes. The NSF\u2019s Very Long Baseline Array (VLBA) solves this problem by looking at radio waves (5 GHz), which pass through dust. With its extremely sharp resolution, finer than a thousandth of an arcsecond, the VLBA can separate close pairs of stars that blur together at other wavelengths.<\/p>\n The NSF\u2019s Very Long Baseline Array (VLBA) can measure motions on the sky as tiny as the width of a human hair seen from thousands of kilometers away, an incredible technical achievement. In practice, this means tracking small shifts in a star\u2019s position over months and years. Each radio telescope in the array records signals with precise timing, and by combining data from antennas spread across the U.S. (from Hawaii to the Virgin Islands), astronomers can pinpoint a star\u2019s location with extreme accuracy. By comparing how that position changes over time, they can detect the subtle orbital motion caused by a companion star and use it to calculate the mass of each star in the system.<\/p>\n In some Orion systems, the measured star masses matched predictions from standard models, but in at least one case, they did not, showing that the models may still need improvement. The observations also revealed hidden close companions and signs that strong magnetic activity can continue even in fairly massive young stars<\/a>.<\/p>\n These young stars in Orion are especially important because they are the building blocks of future planetary systems, much like how our own Solar System began<\/a>.<\/p>\n Dr. Jazmin Ordonez-Toro, postdoctoral Orqu\u00eddeas fellow at the Astronomical Observatory at the University of Nari\u00f1o, said, \u201cThese accurate mass measurements now turn Orion into a precision laboratory for testing how young stars form and evolve. These measurements vastly expand our understanding of how stellar neighborhoods like our own are built.\u201d<\/p>\n Journal Reference:<\/strong><\/p>\n\n