Love at first sight – smitten by a cosmic diamond ring

Astronomers using the European Space Agency’s Very Large Telescope (VLT) in Chile captured this remarkable image of planetary nebula Abell 33. Created when an aging star blew off its outer layers, this beautiful blue bubble happens to be aligned with a foreground star, and bears an uncanny resemblance to a diamond engagement ring. Click to enlarge. Credit: ESO

Such a beautiful sight. You’ve got to love how nature works, creating masterpieces by happenstance. There’s no denying our pleasure in patterns and symmetry. I think it makes us feel connected to the cosmos when we perceive order and organization in what seems at times a chaotic universe. And what’s more iconic than a diamond ring?

Abell 33 and the star HD 83535 are located inside the red circle in the sprawling constellation of Hydra. Although the star is easily seen in binoculars, the nebula itself is a dim object only visible in larger amateur telescopes. Credit: ESO, IAU Sky & Telescope

The pretty blue bubble is the planetary nebula Abell 33 in the constellation Hydra the Sea Snake, which coils across the evening sky this month beneath Leo and Virgo. It’s located 1,500 light years away, while the diamond, a 7th magnitude star named HD 83535, gleams in the foreground only half as far.

The sun spends most of its lifetime slowly burning hydrogen in its core into helium. As it ages, the sun will expand into a red giant with a surface reaching nearly to Mars. Internal changes will later cause it throw off its atmosphere into space in an expanding cloud of gas and dust called a planetary nebula. Click to learn more about the sun’s evolution. Credit: ESO/S. Steinhofel

Planetary nebulae are gassy shells blown off by sun-like stars as they age. Several billion years from now, the sun will bloat up into a red giant star big enough to gulp down the Earth. Powerful winds resulting from pulses of helium burning deep within the sun will blast most of its atmosphere into space, leaving behind an extremely a planet-sized core called a white dwarf.

One of the closest and most familiar white dwarfs is the star Sirius B, the tiny companion to the brilliant wintertime star Sirius. It’s twice as massive as the sun yet 500 miles smaller than Earth. Credit: NASA/ESA

White dwarf stars are exceedingly dense – one teaspoon weighs 5 tons – and are made of carbon and oxygen, the radiant ash left over from the fusion of hydrogen and helium during the sun’s lifetime as a typical star. Our sun fuses these elements in its core to generate the heat and light spring-starved humans need on Earth.

The sun’s surface temperature is around 10,000 degrees F, too hot and bright to stare at without damaging your eyes. But that’s arctic compared to a white dwarf’s temperature of 180,000 degrees! Hot enough that the dwarf emits copious amounts of ultraviolet light causing its former atmosphere, now expanding into space as a shapely nebula, to fluoresce blue, green and pink.

A selection of planetary nebulae photographed by the Hubble Space Telescope. Some show multiple shells from several episodes of strong winds blasting from the core through the outer layers of the stars. Credit: NASA / ESA

Abell 33 is just one of the 86 objects included in astronomer George Abell’s 1966 Abell Catalogue of Planetary Nebulae. Planetaries, as they’re called, are often spherical but not always. Some are shaped like hourglasses, barrels and giant rings. Near the center of Abell 33 you’ll see what appears to be a double star. One of these is the white dwarf, the other might be its companion or it could be another chance alignment.

While planetary nebulae are beautiful in their own right, this particular chance meeting of Abell 33 and HD 83535 is clearly a match made in heaven. Ba-dum-bump!

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