NASA | JPL-Caltech | GSFC | Spitzer | 2016 Aug 29
[c][imghover=http://www.spitzer.caltech.edu/uploaded ... g16-15.jpg]http://www.jpl.nasa.gov/images/spitzer/ ... 914-16.jpg[/imghover]An age-defying star called IRAS 19312+1950 exhibits features characteristic of a veryFor years, astronomers have puzzled over a massive star lodged deep in the Milky Way that shows conflicting signs of being extremely old and extremely young.
young star and a very old star. The object stands out as extremely bright inside a
large, chemically rich cloud of material, as shown in this image from NASA's Spitzer
Space Telescope. IRAS 19312+1950 is the bright red star in the center of this image.
(Credit: NASA/JPL-Caltech)[/c][hr][/hr]
Researchers initially classified the star as elderly, perhaps a red supergiant. But a new study by a NASA-led team of researchers suggests that the object, labeled IRAS 19312+1950, might be something quite different -- a protostar, a star still in the making. ...
Located more than 12,000 light-years from Earth, the object first stood out as peculiar when it was observed at particular radio frequencies. Several teams of astronomers studied it using ground-based telescopes and concluded that it is an oxygen-rich star about 10 times as massive as the sun. The question was: What kind of star?
Some researchers favor the idea that the star is evolved -- past the peak of its life cycle and on the decline. For most of their lives, stars obtain their energy by fusing hydrogen in their cores, as the sun does now. But older stars have used up most of their hydrogen and must rely on heavier fuels that don't last as long, leading to rapid deterioration. ...
Even so, the object didn't entirely fit with evolved stars. Especially puzzling was the smorgasbord of chemicals found in the large cloud of material surrounding the star. A chemical-rich cloud like this is typical of the regions where new stars are born, but no such stellar nursery had been identified near this star.
Scientists initially proposed that the object was an old star surrounded by a surprising cloud typical of the kind that usually accompanies young stars. Another idea was that the observations might somehow be capturing two objects: a very old star and an embryonic cloud of star-making material in the same field. ...
Still, the researchers acknowledge that the object is not a typical protostar. For reasons they can't explain yet, the star has spectacular features of both a very young and a very old star. ...
On the Nature of the Enigmatic Object IRAS 19312+1950:
A Rare Phase of Massive Star Formation? - M. A. Cordiner et al
- Astrophysical Journal 828(1):51 (01 Sep 2016) DOI: 10.3847/0004-637X/828/1/51
arXiv.org > astro-ph > arXiv:1607.00432 > 01 Jul 2016