ITN: Coreshine

[CraigS]

In the NEws:

Shining starlight on the dark cocoons of star birth

Astronomers have discovered a new, cosmic phenomenon, termed "coreshine," which is revealing new information about how stars and planets come to be.
The scientists used data from NASA's Spitzer Space Telescope to measure infrared light deflecting off cores -- cold, dark cocoons where young stars and planetary systems are blossoming. This coreshine effect, which occurs when starlight from nearby stars bounces off the cores, reveals information about their age and consistency. In a new paper, to be published Friday, Sept. 24, in the journal Science, the team reports finding coreshine across dozens of dark cores.
…
Their finding told them that the dust grains were bigger than previously thought -- about 1 micron instead of 0.1 micron (a typical human hair is about 100 microns).
That might not sound like a big difference, but it can significantly change astronomers' models of star and planet formation. For one thing, the larger grain size means that planets -- which form as dust circling young stars sticks together -- might take shape more quickly. In other words, the tiny seeds for planet formation may be forming very early on, when a star is still in its pre-embryonic phase.

Interesting phenomenon. I'll be thinking of it next time I look at those Deep Space Forum Nebula shots.

Cheers

[renormalised (Carl)]

Interesting...it would be interesting to find out how large the dust grains are, initially, when the clouds first form.

[CraigS]

Originally Posted by renormalised

Interesting...it would be interesting to find out how large the dust grains are, initially, when the clouds first form.

From the other thread .. 'Kuiper Belt, Dust & Neptune', scientists have created a simulation model relating to the movement of differing dust particles, then run their motion forwards in time, up to the present day ...

With the help of NASA's Discover supercomputer, the researchers kept tabs on 75,000 dust particles as they interacted with the outer planets, sunlight, the solar wind -- and each other.
The size of the model dust ranged from about the width of a needle's eye (0.05 inch or 1.2 millimeters) to more than a thousand times smaller, similar in size to the particles in smoke. During the simulation, the grains were placed into one of three types of orbits found in today's Kuiper Belt, at a rate based on current ideas of how quickly dust is produced.

I'd say from the sound of this, that someone seems to think 1.2μm is about the right size for a dust particle 700 million years ago. (Mind you, that may be their computing limit, also).



Cheers