Indian scientists have identified 57 variable stars in the open cluster NGC 381, reported by Science X Network.
An open star cluster consists of a single giant molecular cloud whose light is shared among many stars. In such a group, the luminous members are gravitationally bound but can drift apart as they traverse the galaxy. Across the Milky Way, astronomers catalog more than a thousand of these clusters. Mapping their distribution helps scientists understand the history and evolution of the universe.
NGC 381 is located roughly 3,700 light-years from Earth in the Cassiopeia constellation. The cluster is middle-aged at around 447 million years, spans about 15 light-years in radius, and contains an estimated 32.4 solar masses. Researchers from India conducted observations using the 1.3-meter Devasthal optical telescope. They noted that their team continuously monitored the region around NGC 381 in the V and I photometric bands to track shifting stars. Data collection occurred over 27 nights, beginning October 1, 2017 and concluding January 14, 2019, across a full year of observing time, with the aim of capturing precise stellar brightness variations.
From these efforts, the researchers confirmed a total of 57 variable stars in the NGC 381 region, with five of them belonging to the cluster itself. The stars were categorized based on the shape of their light curves, the magnitude of their brightness changes, and their placement on the Hertzsprung-Russell Diagram, which links a star’s spectral type to its luminosity and mass. [Source: Science X Network attribution]
Among the 57 variables, ten are eclipsing binaries, meaning their brightness varies as one companion star blocks light from its partner. Fifteen are identified as rotating variables, where changes in brightness arise from surface features or geometric effects tied to rotation. Two stars show pulsating behavior, expanding and contracting in a regular rhythm. The remaining thirty stars do not fit neatly into these predefined classes, highlighting the diverse and sometimes enigmatic nature of stellar variability within the cluster. This diversity provides astronomers with a natural laboratory to study stellar evolution and dynamics in a controlled setting. [Source: Science X Network attribution]