Sun's "Twin" Found, As Embryo
Courtesy University of Colorado at Boulder
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“We think this is a very, very early version of our own sun,” said research team member Jeffrey Linsky of JILA, a research institute at Boulder, Colo. The object seems to be evolving in a violent environment much like the one believed to have spawned our sun, he added.
The body, dubbed E42, lies in the Eagle Nebula—a cloudy, star-forming region estimated to be 7,000 light-years away. A light-year is the distance light travels in a year.
The stellar embryo lurks in a famously photogenic part of the nebula called the Pillars of Creation, Linsky said. His team released a new image of the Pillars consisting of a Hubble Space Telescope image overlaid with data from NASA’s Chandra X-ray Observatory, which was used in the research.
The instrument served to detect X-rays coming from the body. The image, with red, green and blue dots representing low-, medium- and high-energy X-rays, shows relatively few X-ray sources in the Pillars, Linsky said; this would suggest the area is past its star-forming prime.
E42 is one of dozens of structures in the Pillars identified as Evaporating Gas Globules, regions of dense gas that may produce stars. Stars form from clouds of gas and dust that collapse under their own gravity after becoming sufficiently dense.
But just four of the globules in the Pillars are massive enough to make stars, Linsky said. Of those, he added, E42 is the only one with a sun-sized mass; that’s theoretically enough basis to suppose it will develop into something much like our sun.
“The four proto-stars that we have identified on the edges of the pillars are probably the youngest stars ever imaged by astronomers,” Linsky said. Since neonatal stars are shrouded in gas and dust, they emit little or no visible light. But astronomers found in 2000 that they can emit powerful, and detectable, X-rays.
Earth’s sun is thought to have formed some five billion years ago after clouds of dust and gas were seared by ultraviolet radiation and blasted by one or more supernovae—explosions of dying stars, Linsky said. “The sun was likely born in a region like the Pillars of Creation because the chemical abundances in the solar system indicate that a supernova occurred nearby and contributed its heavy elements” to our system.
A January study by French astronomers suggested the pillars were toppled some 6,000 years ago by a nearby supernova, as evidenced by a glowing cloud of scorched dust next to the pillars. Since they’re about 7,000 light years away, the French team contends they will still be visible from Earth as “ghost images” for another thousand years or so.
“My guess is that the shock wave from the supernova may have been far enough away so that E42 and some of the other stars may have survived,” said Linsky. “But I guess we will have to wait another thousand years or so to get the answer.”
A paper on the new findings appeared in the Jan. 1 issue of The Astrophysical Journal.
JILA, Linsky’s center, originally stood for Joint Institute for Laboratory Astrophysics. But it no longer stands for anything, because its fellows declared in 1994 that the research done there would go well beyond that field. It’s jointly run by the University of Colorado at Boulder and the National Institute of Standards and Technology in Gaithersburg, Md.