We have been negligent in keeping the Stardust@home community up to date about our progress. We apologize for this, and hear your frustration. Our excuse is that we have been very very busy readying ourselves for publication of the first results from the ISPE.
Here’s the brief status. We apologize in advance for the jargon and acronyms, but from previous posts and narrated slideshows these should be decipherable. So far through Stardust@home you have identified 71 bona fide tracks. There are several new midnight tracks that have not yet been extracted.
On Stardust@home there has been quite a lot of activity recently regarding the skill score. We are currently having a runoff among the favorite competing proposals. Dave Frank and colleagues at JSC are preparing to pull several new tiles from the tray for scanning. It is very time-consuming because of the need to place fiducials “pokes” in the tiles to record position and monitor distortion. We recently extracted two midnight tracks. One track, track 42, was analyzed by STXM at the ALS and found to be Al metal, so it originated as a secondary from the SRC deck. An FTIR analysis by George Flynn at the NSLS showed no detectable organics in this track. The other track, track 41, is firmly stuck on its extraction microfork, so we may have to take the risk of analyzing it on the fork instead of transferring it to a silicon nitride window sandwich, which is vastly preferable. Or we may be forced to make a new fixture. We have been very active in analyzing our backgrounds, in order to rule out completely the possibility of confusion of our four candidates with background. Our assessment is that this very unlikely, but extraordinary claims — that we have found the first interstellar dust particles ever – require extraordinary evidence and care. We analyzed by STXM track 35, a bona fide sample of the SRC deck, for the Ni and Mo concentrations, to compare with recent SEM/EDX analyses of a sample of anodized Al around a rivet on the sample tray arm identified by Mike Zolensky at JSC. (This sample shows very high Ni and Mo in the anodization.) We found very low levels, which indicates that this sample is not indicative of the SRC anodized Al. So we have requested a sample of this material from the actual spacecraft in the Smithsonian, and are waiting impatiently for word on our request.
We have been modeling interstellar and interplanetary dust propagation in the solar system, and our models indicate an extremely low probability of the four current candidates being samples of the IDP population. The interstellar dust modeling by Veerle Sterken and Andrew Westphal indicates that the low-velocity candidates (Orion/Sirius, Hylabrook, and Merlin) may be in the tail of a population of high-beta particles, implying that a significant fraction of IS dust consists of fluffy, low-density agglomerates. We are preparing a series of approximately 11 papers on the ISPE for publication.
Thank you for your hard work on Stardust@home. As you can see, there is a lot going on.
We will try to be better about communication what is happening!