Over 3,000 light years away, a “cosmic butterfly” rears its vibrantly colored wings amongst a meadow of glowing stars. These bubbles of sky blue and fuschia gas were captured by the Very Large Telescope at the European Southern Observatory (ESO) in Chile, and haven’t yet been captured in such stunning, intricate detail.
The swath of gas, a planetary nebula named NGC 2899, is nestled somewhere between 3,000 and 6,500 light years away in the constellation Vela, which is visible from Earth’s southern hemisphere.
Planetary nebulae were first named by astronomer William Herschel in 1782, who cited their resemblance to planets—but the structures are actually the last heroic stands of enormous, dying stars. After they’ve run out of fuel to burn, which can happen after anywhere from millions to a trillion years into their lifespans, these dying stars collapse, blowing off shells of element-rich gas reaching up to tens of thousands of degrees Celsius. The gas expands up to two light years from the nebula’s center and glows with intense ultraviolet radiation, which lights up these nebulae.
In the case of NGC 2899, the hydrogen gas glows red-purple in a halo around a cloud of bluish oxygen in the center. It will shine brightly for just a few thousand years—a relatively transient phenomena in terms of astrological time.
The delicate, butterfly shape is rare—only 10 to 20 percent of nebulae exhibit this double-lobed shape. It happens when one of two central stars collapses and sheds its gassy layers, creating a typical symmetrical nebula. Then, the other star interferes with the expansion of gas, bending the nebula into lobes to create this butterfly shape.
To image the dazzling display, astronomers at the Paranal Observatory in Chile used the Very Large Telescope perched on Cerro Paranal, a mountain in the Atacama Desert. The device can image celestial phenomena that’s four billion times fainter than what the human eye can perceive, according to ESO—and that’s thanks to its four distinct 8.2-meter-wide telescopes. In particular, the FOcal Reducer and low dispersion Spectrograph (FORS) helped craft this beautiful, high-resolution image through a special wavelength-detection system. In addition to spotting awe-inducing butterfly nebulae, FORS has revealed observations of gravitational waves, an interstellar asteroid, and has been used to study the physics behind the formation of planetary nebulae.