Planetary Nebula Abell 33 — A Star In Its Death Throes
Credit: ESO
Wow! I’ve seen some gorgeous astro-images, but this one is just so evocative! This is what it looks like when a star about like our Sun blows off its outer layers as it ages. It becomes a planetary nebula, so named by astronomer Sir William Herschel because these dim little wisps of light looked like what he thought newborn planetary systems looked like through his low power (by today’s standards) telescope.
In this case, the star has expelled its top layers to space and the material has expanded to form a gorgeous blueish balloon of material. The edge of the bubble just happens to be aligned with a nearby star, and the combo of light and glowing stellar material is just gorgeous.
Astronomers using the European Southern Observatory’s Very Large Telescope in Chile captured this sight using data from the FORS Spectrograph attached to the Very Large Telescope. The scene it witnessed is a familiar one to those who study the lives and deaths of sun-like stars.
Most stars with masses similar to that of our Sun will end their lives like this. First, they blow off their atmospheres, which creates glowing and often colorful clouds called planetary nebulae. In this case, the cloud is surrounding what’s left of the progenitor star (the one that’s dying) is just slightly off-center in the image. It’s shrinking as it ages, and will end its days as a white dwarf. It looks dim here, but actually, the aging star is much more luminous than the Sun. It’s giving off tremendous amounts of ultraviolet radiation, which is causing the bubble of material to glow.
This particular planetary nebula, called Abell 33, lies some 2,500 light-years from Earth. Its perfectly round shape is somewhat unusual. Oftentimes there is more than one star involved in one of these stellar death scenes. Sometimes it’s one star of a binary pair that starts to die — and that affects the shape of the resulting planetary nebula.
This is one of the reasons I love astronomy. Just when you think you’ve seen it all, the universe tosses another gorgeous vision your way.