The Rosette Eye: the key transition phase in the birth of a massive star

TL;DR

This paper reports the discovery of a transient phase in the formation of a massive star, characterized by ultraviolet radiation breaking through its natal core and revealing a unique morphology called the Rosette Eye.

Contribution

It presents the first observation of a key early phase in massive star formation, highlighting the morphology and physical processes involved.

Findings

Resolved the Rosette Eye morphology in near-infrared.

Detected ionized outflows and an accretion disk signature.

Observed static H2 emission arcs indicating fluorescence.

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 $\sim$ 10$^5$ 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 H$_{2}$ emission produced by fluorescence. This study has strong implications for our understanding of how massive stars embark on their formation.