HD 56925

A type WR star within the Thor's Helmut emission nebula. The powerful star emits a high velocity wind, pushing matter ahead of it. This process both compresses and expands its ring-like shell. As it grows, it collects even more gas and dust from the interstellar medium. The kinematics, morphology, mass and density are clearly stratified with respect to the WR star, with three different velocity components.

These features reveal the recent evolutionary history of HD 56925, because the multiple layers could be associated to several energetic events which have acted upon the surrounding circumstellar medium. Hence, a careful study of the different shockfronts contain clues in determining the present and past interaction of this evolved massive star with its surroundings.

While most planetary nebulae contain old stars nearing the end of their lives, the central WR star in NGC 2359 is very young. Its ultraviolet photons are the fueling source of the emission nebula. WRs are evolved, massive and extremely hot – up to ~50,000 K. Not only that, but their luminosity is incredible, too. Their surface composition is extremely exotic, being dominated by helium rather than hydrogen and the stars themselves are rare, simply because they are so short-lived.]]