The cosmic cloud known as W50 formed when a giant star, 18,000 light-years away in the constellation of Aquila, exploded as a supernova around 20,000 years ago.
The explosion sent its gases flying outward in an expanding bubble that is now nearly 700 light-years across, astronomers at the National Radio Astronomy Observatory said in a release.
Astronomers say they believe a black hole lurks at the supernova's center, feeding on gas from a close companion star, while powerful magnetic fields light up the surrounding gas in the radio wavelengths.
Astronomical objects visible to the eye and optical telescopes often are nicknamed for their earthly likenesses. When the new image of W50 reached the NRAO director's office, its shape immediately suggested a manatee, the endangered marine mammals known as "sea cows" that congregate in warm waters in the southeastern United States.
Therefore, the NRAO has adopted a new nickname for W50: the Manatee Nebula.