An ancient, red giant star in the throes of a frigid death has produced the coldest known object in the cosmos: the Boomerang Nebula. But how was this star able to create an environment so much colder than the natural background temperature of deep space?
The answer, according to astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA), may be that a small companion star has plunged into the heart of the red giant, ejecting most of the matter of the larger star as an ultra-cold outflow of gas and dust. Raghvendra Sahai, an astronomer at NASA's Jet Propulsion Laboratory in Pasadena, California, led a study on the mysterious nebula that appears in The Astrophysical Journal.