In this new Hubble image, the strikingly luminous star AG Carinae
— otherwise known as HD 94910 — takes centre stage. Found within the
constellation of Carina in the southern sky, AG Carinae lies 20 000
light-years away, nestled in the Milky Way.
AG Carinae is classified as a Luminous Blue Variable. These rare objects are massive evolved stars that will one day become Wolf-Rayet Stars —
a class of stars that are tens of thousands to several million times as
luminous as the Sun. They have evolved from main sequence stars that
were twenty times the mass of the Sun.
Stars like AG Carinae lose their mass at a phenomenal rate. This loss
of mass is due to powerful stellar winds with speeds of up to 7 million
km/hour. These powerful winds are also responsible for the shroud of
material visible in this image. The winds exert enormous pressure on the
clouds of interstellar material expelled by the star and force them
into this shape.
Despite HD 94910’s intense luminosity, it is not visible with the naked eye as much of its output is in the ultraviolet.
This image was taken with the Wide Field and Planetary Camera 2
(WFPC2), that was installed on Hubble during the Shuttle mission STS-61
and was Hubble’s workhorse for many years. It is worth noting that the
bright glare at the centre of the image is not the star itself. The star
is tiny at this scale and hidden within the saturated region. The white
cross is also not an astronomical phenomenon but rather an effect of
the telescope.
