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Sun’s “twin” found, as embryo

Feb. 16, 2007
Courtesy University of Colorado at Boulder
and World Science staff

As­tro­no­mers say they have peered at the em­bry­o of a star that will prob­a­bly de­vel­op in­to a vir­tu­al twin of our sun. It’s one of four new­found “proto-stars” that are prob­a­bly the youngest stars as­tro­no­mers have ev­er im­aged, the re­search­ers said.

Click for large version

Top: a mag­ni­fi­ca­tion of the boxed re­gion of the bot­tom im­age, show­ing the ar­ea of E42. Bot­tom: a wid­er view of the Pil­lars of Cre­a­tion. (Im­age cour­te­sy NASA/ESA/STScI, J. Hes­ter and P. Scowen (ASU)).


“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.


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Astronomers report that they have peered at the embryo of a star that will probably develop into a virtual twin of our sun. It’s one of four newfound “proto-stars” that are probably the youngest stars astronomers have ever imaged, the researchers said. “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, Linsky added. The body, dubbed E42, lies in the Eagle Nebula—a cloudy, star-forming region in nearby space estimated to be 7,000 light-years from Earth. A light-year is the distance light travels in a year. The stellar embryo lurks in a famous, much-photographed part of the nebula called the Pillars of Creation, Linsky said, and is probably in the earliest stage astronomers have ever detected a star like the sun. 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 image, with red, green and blue dots representing low-, medium- and high-energy X-rays, shows there are relatively few X-ray sources in the pillars, Linsky said, suggesting it’s past its star-forming prime. E42 is one of many structures in the Pillars identified as Evaporating Gas Globules, regions of dense gas where stars may be forming. Stars form from clouds of gas and dust that collapse under their own gravity after becoming sufficiently dense. But just four of these globules are massive enough to form a star, Linsky said. Of those, he added, E42 is the only one with a sun-sized mass, which is theoretically enough 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. Earth’s sun is thought to have formed some 5 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 explosion, as evidenced by a glowing cloud of scorched dust adjacent 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.”