Hubble images show giant star on edge of destruction

NASA's Hubble Space Telescope has spotted a brilliant "celebrity star," one of the brightest stars seen in our galaxy, surrounded by a glowing halo of gas and dust and living on the edge of destruction.

The star, called AG Carinae, is a few million years old and resides 20,000 light-years away inside our Milky Way galaxy. It is estimated to be up to 70 times more massive than our Sun and shines with the blinding brilliance of one million suns.

The price for its opulence is "living on the edge." It is waging a tug-of-war between gravity and radiation to avoid self-destruction.

Hubble's sharp vision revealed the most prominent features of AG Carinae -- filamentary structures shaped like tadpoles and lopsided bubbles. These structures are dust clumps illuminated by the star's reflected light.

The tadpole-shaped features, most prominent at left and bottom, are denser dust clumps that have been sculpted by the stellar wind.

The image was taken in visible and ultraviolet light. Ultraviolet light offers a slightly clearer view of the filamentary dust structures that extend all the way down toward the star. Hubble is ideally suited for ultraviolet-light observations because this wavelength range can only be viewed from space.

The mammoth star was created from one or more giant eruptions about 10,000 years ago. The star's outer layers were blown into space -- like a boiling teapot popping off its lid. The expelled material amounts to roughly 10 times our Sun's mass.

These outbursts are the typical life of a rare breed of star called a luminous blue variable.

Like many other luminous blue variables, AG Carinae remains unstable. It has experienced lesser outbursts that have not been as powerful as the one that created the present nebula.

Although AG Carinae is quiescent now, as a super-hot star it continues pouring out searing radiation and powerful stellar wind (streams of charged particles). This outflow continues shaping the ancient nebula, sculpting intricate structures as outflowing gas slams into the slower-moving outer nebula.

Massive stars, like AG Carinae, are important to astronomers because of their far-reaching effects on their environment.