Astronomers Uncover Thousands of Hidden Stars Related to the Seven Sisters

Astronomers at the University of North Carolina at Chapel Hill have unveiled a groundbreaking discovery regarding the Pleiades star cluster, commonly known as the Seven Sisters. This well-known cluster, long thought to be compact, is now understood to be merely the bright heart of a vast network of stars.

By utilizing data from NASA's Transiting Exoplanet Survey Satellite, or TESS, alongside the European Space Agency's Gaia space telescope, researchers identified thousands of additional stellar relatives, coining the term Greater Pleiades Complex for this expansive structure.

The research indicates that the Pleiades cluster is approximately twenty times larger than previously believed. Stars typically form in groups, but as they age, these groups disperse, complicating efforts to track their origins.

The team employed stellar rotation as a cosmic clock, revealing that younger stars spin rapidly while older stars exhibit slower rotation. This innovative approach allowed them to locate many long-lost members of the Pleiades scattered across the sky.

Andrew Boyle, the lead author of the study and a graduate student in physics and astronomy, remarked that this research transforms the Pleiades from merely seven bright stars into a vast assembly of siblings across the celestial sphere.

The cultural implications of this discovery are significant, as the Pleiades has been an important reference point for young stars and exoplanets throughout history. It holds cultural significance in various societies, appearing in the Old Testament and the Talmud, celebrated as Matariki in New Zealand, and represented in the Subaru logo in Japan.

Co-author Andrew Mann, a professor of physics and astronomy, highlighted that their findings suggest stars near the Sun might belong to larger stellar families, enhancing our understanding of the cosmos.

This research not only maps hidden structures in the Milky Way but also proposes that many star clusters once thought isolated are, in fact, part of extensive stellar families. By studying stellar rotation, the researchers developed a new method to explore the complex architecture of our Galaxy.

They believe this approach could shed light on the origins of our Sun, determining if it formed within a similar extensive stellar group. Understanding how stars and planets are born is crucial for reconstructing the environments of solar systems, including our own.

The research paper detailing these findings is accessible in The Astrophysical Journal.