A Dying Star's Radio Spiral
Oct. 19, 2012 --
Meet R Sculptoris, a dying star that is shedding its outer layers of gas, generating a beautiful spiral of radio emissions. This amazing sight was captured by the newly commissioned Atacama Large Millimeter Array (ALMA) in the Chilean desert. Although rare, this kind of space spiral isn't unprecedented. In fact, there have been several spirals seen in recent years that have excited, spooked, but, above all, awed onlookers -- here are a few of the most memorable.
Hubble's Ghost Spiral In 2010, the Hubble Space Telescope imaged a ghostly pinwheel spiral surrounding a binary star system called LL Pegasi. This bizarre cosmic phenomenon is caused by one of the stars dying, venting huge amounts of gas and dust into space. As the stars orbit one another every 800 years, the material expands into space like water being sprayed from a spinning garden sprinkler.
The Failed Missile Spiral Probably the most striking example in recent years is that of the mysterious expanding shape that appeared over northern Norway on Dec. 9, 2009. Reflecting the early morning Arctic light, this vast spinning cloud expanded above the horizon, spraying a white spiral and blue tail. Conspiracy theories swarmed as soon as photographs and videos hit the media. Was it a portal to another dimension? Did a black hole just appear in our atmosphere? Was the restarted Large Hadron Collider responsible? As it turned out, the spiral was caused by a Russian missile after a failed test launch. The rocket, designed to carry nuclear warheads, spun out of control spewing fuel into the upper atmosphere, creating this beautiful spiral display.
The Death Star Spiral What a kerfuffle WR 104 caused in 2008. The Wolf-Rayet star first gained attention when astronomers admired its spectacular spiral created by stellar winds colliding with the winds of its binary partner. But then we realized something. The Wolf-Rayet was dying, violently. And its violent death meant the massive star could collapse and generate one of the most powerful explosions in the cosmos: a gamma ray burst (or GRB). WR 104 is only 8,000 light-years from Earth, and the fact that we can see its full spiral means that we are looking down the barrel of this potentially damaging GRB. Naturally, many people were concerned that we could become GRB toast and in the eyes of the media, WR 104 was dubbed the "Death Star." Fortunately in 2009, Discovery News spoke with Wolf-Rayet star expert Grant Hill, of the Keck Observatory in Hawaii, who has other ideas about the deadly potential of WR 104.
The UFO Spiral UFO reports are often vague and include shaky video footage of a fuzzy light in the sky. However, when the Australian press announced the arrival of a bizarre spiraling light over the Gold Coast in June 2010, many eyewitnesses captured high quality video and photographs of the event. At the time, this "UFO" stayed true to its description; it was certainly an unidentified flying object. But it didn't stay unidentified for long; the sightings coincided with the maiden flight of SpaceX's Falcon 9 rocket. The spiraling effect was caused by a slight engineering fault causing the rocket to spin slowly, venting exhaust in a partial spiral.
The Recurrent Nova Spiral We've all heard of supernovae, but what are "recurrent novae"? In the case of the binary star system RS Ophiuchi, a small but dense white dwarf star orbits with a large, puffy red giant that is shedding huge quantities of matter. This matter is blasted into space in the form of a strong stellar wind, forming a spiral. Interestingly, in this star system, the white dwarf captures some of the gas from its companion star, gradually accumulating it. Once the gas reaches a critical mass and temperature, a massive explosion occurs, wiping out the expanding spiral. The process then repeats every 20 years or so. For more about this special star system and how novae can help to enrich the interstellar medium with heavy elements, read the Discovery News IM interview with nova expert Richard Barry of NASA Goddard Space Flight Center.
