PDA

View Full Version : XMM-Newton Analyzes a Huge Collection of Newly Forming Stars



Fraser
2007-May-31, 07:34 PM
After surveying more than 200 stars in various stages of formation, ESA's XMM-Newton X-Ray Observatory has revealed a dramatically different picture than what astronomers were predicting. ...

Read the full blog entry (http://www.universetoday.com/2007/05/31/xmm-newton-analyzes-a-huge-collection-of-newly-forming-stars/)

Jerry
2007-Jun-04, 01:37 PM
Astronomers expected that the infalling material would heat the stellar envelop so much that it should produce an excess of X-rays as well. But that wasn’t happening. Instead, it appears that the streams of material are so dense, they actually cool the outer atmosphere, and absorb most of the X-rays being emitted.
Perhaps it is time to revisit the star formation and life cycle theories that have been around so long and worked so well, before X-ray vision.

Here is a new paper, reviewing the status of r-process (metallic evolution via nucleosynthesis) research (Caution, 4+megabytes...):

http://arxiv.org/PS_cache/arxiv/pdf/0705/0705.4512v1.pdf

The r-process of stellar nucleosynthesis:Astrophysics and nuclear physics achievements and mysteries



...The chronometric predictions based on the observations of Th and U in very metal-poor stars have to be considered with great
care as well. In order for them to be reliable, it is not only required that the production of the actinides by the r-process is well known, but, and very decisively, that the production of Th with respect to U and to the Pt peak is `universal.' Observation seemingly demonstrates now that this is not the case.

The bottom line of this review is that unanswered questions are by far more numerous than solved problems when one is dealing with the r-process. This is a very pleasing situation, as hope for many exciting discoveries is still ahead of us.(my bold)