Animal-shaped nebula has an earthly doppelganger, say astronomers

January 20, 2013

Animal-shaped nebula has an earthly doppelganger, say astronomers

Animal-shaped nebula looks like a Florida manatee.

The National Science Foundation’s Karl G. Jansky Very Large Array recently released a new view of a 20,000-year old supernova that closely resembles a much-beloved endangered species, the Florida Manatee. The image also offers more clues to the history of this amazing celestial wonder.

According to a news release from the National Radio Astronomy Observatory (NRAO), W50 is one of the biggest supernova remnants ever spotted by the VLA. W50 is about 700 light years across, covering two degrees on the sky (that’s the span of four full Moons, say astronomers).

Astronomers believe that the W50 cloud formed when a giant star, thousands of light years away in the constellation of Aquila, exploded as a supernova around twenty thousand years ago, blasting its outer gases outward in an expanding bubble.

They think that the remaining, gravitationally-crushed relic of that giant star feeds on gas from a companion star. The cannibalized gas gathers in a disk around the black hole. The disk and black hole’s network of powerful magnetic field lines behaves like a huge railroad system to grab charged particles out of the disk and channel them outward in powerful jets moving at nearly the speed of light. This system, known collectively as the SS433 microquasar, shines brightly in both radio waves and X-rays.

According to astronomers, the microquasar’s jets have pushed their way through the expanding gases of the W50 bubble, eventually slamming bulges outward on either side. The jets also create stunning corkscrew patterns across the inflating bulges.

Astronomical objects, such as W50, are often given names for their earthly doppelgangers. W50 received its rather dull name by being the 50th radio source listed in the Westerhout Catalog.

However, when Heidi Winter, the NRAO Director’s Executive Assistant, first saw the VLA’s W50 image she was immediately reminded of a manatee, the endangered marine mammal that swims in warm water in the southeastern United States.

Florida manatees, a subspecies of the West Indian manatee, average around 10 feet long, weigh over 1000 pounds and spend nearly eight hours a day munching on sea plants. When they aren’t eating, they are usually resting on their backs with their flippers crossed over their large bellies, in a pose that looks a lot like W50.

Unfortunately, painful and sometimes deadly encounters with boat propellers carve deep, curved scars similar in display to the arcs created by the powerful jets on the W50 remnant. Boat propellers, however, aren’t the only threat to a manatee’s well being.

A manatee in Fort De Soto Park recently had to endure the embarrassment of giving an unwanted rid to a swimmer. Ana Gloria Garcia Gutierrez of St. Petersburg, Florida, allegedly admitted to riding the manatee, and said she not know that doing so was illegal. The manatee is not thought to have been harmed during the incident.

The NRAO has adopted a new and much more interesting nickname for W50: The Manatee Nebula.

Photo credit: NSF’s Karl G. Jansky Very Large Array (VLA), NRAO/AUI/NSF, K. Golap, M. Goss; NASA’s Wide Field Survey Explorer (WISE).


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