The Rosette Eye: the key transition phase in the birth of a massive star
Abstract
Massive protostars dramatically influence their surroundings via accretion-induced outflows and intense radiation fields. They evolve rapidly, the disk and infalling envelope being evaporated and dissipated in 105 years. Consequently, they are very rare and investigating this important phase of early stellar evolution is extremely difficult. Here we present the discovery of a key transient phase in the emergence of a massive young star, in which ultraviolet radiation from the new-born giant has just punctured through its natal core. The massive young stellar object AFGL 961 II is readily resolved in the near infrared. Its morphology closely resembles a cat's eye and is here dubbed as the Rosette Eye. Emerging ionized flows blow out an hourglass shaped nebula, which, along with the existence of strong near-infrared excess, suggests the existence of an accretion disk in the perpendicular direction. The lobes of the hourglass, however, are capped with arcs of static H2 emission produced by fluorescence. This study has strong implications for our understanding of how massive stars embark on their formation.