A decade of observations from NASA’s WISE and NEOWISE missions has uncovered just how chaotic the early lives of young stars truly are. In one of the largest mid-infrared variability studies ever conducted, researchers at the Aryabhatta Research Institute of Observational Sciences (ARIES) analyzed light curves of more than 22,000 young stellar objects (YSOs), revealing dramatic and unpredictable brightness changes during their formative years.
Published in The Astrophysical Journal Supplement Series, the study reports that roughly 26% of YSOs show measurable variability. The youngest Class I stars—still wrapped in thick cocoons of gas and dust—were significantly more erratic than their older Class III counterparts. Their flickers arise from unstable accretion bursts, shifting disk structures, and rapid changes deep within their dusty envelopes. The team identified six variability types: linear, curved, periodic, burst, drop, and irregular.
Colour shifts added another layer of insight. Most variable YSOs reddened as they brightened, suggesting heating or dust-related effects, while a smaller but intriguing group turned bluer—likely signalling intense accretion events or clearing within their inner disks.
With more than 5,800 variable stars catalogued, the dataset offers one of the clearest infrared windows yet into how stars evolve, and eventually break free of their birth clouds.
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