Stellar spin may explain fading black hole flares

Astrophysicists at Syracuse University have identified a potential explanation for why successive light flares from repeating partial tidal disruption events (rpTDEs) grow progressively dimmer. A study published in The Astrophysical Journal suggests that a star’s spin, a previously overlooked factor, may be the cause.

In these events, a star passing near a supermassive black hole is not completely destroyed but loses a fraction of its mass during each close pass. This process creates a flare of light as stellar debris falls toward the black hole. While theoretical models previously struggled to explain the diminishing brightness of these recurring flares, the new research indicates that the internal rotation and spin of the star play a critical role in how much material is shed during each encounter.