Hunting Massive Stars with Herschel

W3 star-forming complex  Image credit: ESA/PACS & SPIRE consortia, A. Rivera-Ingraham & P.G. Martin, Univ. Toronto, HOBYS Key Programme (F. Motte)

 

In this new view of a vast star-forming cloud called W3, the Herschel space observatory tells the story of how massive stars are born. Herschel is a European Space Agency mission with important NASA contributions. W3 is a giant gas cloud containing an enormous stellar nursery, some 6,200 light-years away in the Perseus Arm, one of our Milky Way galaxy’s main spiral arms.

By studying regions of massive star formation in W3, scientists have made progress in solving one of the major conundrums in the birth of massive stars. That is, even during their formation, the radiation blasting away from these stars is so powerful that they should push away the very material from which they feed. If this is the case, how can massive stars form at all?

Observations of W3 point toward a possible solution: in these very dense regions, there appears to be a continuous process by which the raw material is moved around, compressed and confined, under the influence of clusters of young, massive stars called protostars.

Through their strong radiation and powerful winds, populations of young, high-mass stars may well be able to build and maintain localized clumps of material from which they can continue to feed during their earliest and most chaotic years, despite their incredible energy output.

 
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Saturn is Like an Antiques Shop, Cassini Suggests

Three of Saturn's moons

The Cassini spacecraft observes three of Saturn’s moons set against the darkened night side of the planet.
Image credit: NASA/JPL-Caltech/Space Science Institute

A new analysis of data from NASA’s Cassini spacecraft suggests that Saturn’s moons and rings are gently worn vintage goods from around the time of our solar system’s birth.

Though they are tinted on the surface from recent “pollution,” these bodies date back more than 4 billion years. They are from around the time that the planetary bodies in our neighborhood began to form out of the protoplanetary nebula, the cloud of material still orbiting the sun after its ignition as a star. The paper, led by Gianrico Filacchione, a Cassini participating scientist at Italy’s National Institute for Astrophysics, Rome, has just been published online by the Astrophysical Journal.

“Studying the Saturnian system helps us understand the chemical and physical evolution of our entire solar system,” said Filacchione. “We know now that understanding this evolution requires not just studying a single moon or ring, but piecing together the relationships intertwining these bodies.”

Data from Cassini’s visual and infrared mapping spectrometer (VIMS) have revealed how water ice and also colors — which are the signs of non-water and organic materials –are distributed throughout the Saturnian system. The spectrometer’s data in the visible part of the light spectrum show that coloring on the rings and moons generally is only skin-deep.

Using its infrared range, VIMS also detected abundant water ice – too much to have been deposited by comets or other recent means. So the authors deduce that the water ices must have formed around the time of the birth of the solar system, because Saturn orbits the sun beyond the so-called “snow line.” Out beyond the snow line, in the outer solar system where Saturn resides, the environment is conducive to preserving water ice, like a deep freezer. Inside the solar system’s “snow line,” the environment is much closer to the sun’s warm glow, and ices and other volatiles dissipate more easily.

 

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Learning Space

Jeff and Terry Menz  from our very own club joined Nicole Gugliucci and Georgia Bracey for the Learning Space Hangout on Google + brought to you by Cosmoquest