Talk:PRS Small Bodies Facets
Dust studies. What about gas?
We have a facet for dust studies, which is appropriate. Should there be "gas studies" ? [msk]
[AR] Don't know if this helps, but for "dust studies" we have a fair number of data sets with a target of "Dust" and measurements that are called things like "mass spectra", "time of flight spectra", "spatial distribution", and such. I don't know of anything analogous for gas. Are there such data sets, and if so how do they describe themselves now in terms of target and observation type?
[mfa] We will have purely gas datasets, e.g., from the ROSINA instrument on Rosetta. We may have some in the IHW datasets from IMS and/or NMS. Most other datasets addressing gas have dust mixed in, i.e., many people study dust without gas, but few people study gas without dust, if for no other reason than the need to get rid of the signal from the dust.
[AR] The small number of affected data sets in our current holdings makes me think we should hold of making a decision until we get to the point of actually ingesting or migrating this sort of data. Then we can assess where Atmospheres is at and what capabilities we want to provide for our users, and update the standard value list accordingly.
Surfaces, interiors, and atmospheres
My guess is that studies of surfaces (reflectance, gelogical maps) and interiors (seismology, excavation, models) belong to physical properties, and we may want to add something to that effect before "etc." However, are we OK with atmospheric studies (e.g., of KBOs) being categorized with the atmospheres discipline? [msk]
[AR] Atmospheres has one of the simplest facet lists - just one facet, with just two values "structure" and "meteorology". Now, part of this is that they're dragging feet, but looking at the sort of data on the Atmospheres website, would you expect similar data products for KBOs? If so, then the Atmospheres facets will work. If you think the sort of results we might get would be substantially different, then we either sweep it up under small bodies or coordinate with Atmospheres on their facet lists. They're a bit preoccupied with MAVEN at the moment, but I suspect a reasonable proposal would be accepted.
[mfa] Noting that a cometary coma is an atmosphere (or at least an exosphere, which may be what Pluto has per some models), and noting that atmospheres include dust, I think that if we are to have an atmospheres facet it needs to be very different from the one for the atmospheres discipline, which means we need to characterize it differently.
[AR] That makes sense to me. Atmospheres (the node) is mainly concerned with stable and complex atmospheric systems in the gas giants. The situation on small bodies is clearly different, as the approaches to studying them would presumably be. But as with "gas" (maybe these are closely related?) I would tend to hold off on defining any small body facets until we have a good selection of data sets in hand or an immediate need.
[mfa] Do we want the sub-facets in now? Or do we just want to put words in the facet description describing these possible future sub-facets?
[AR] I could go either way. At the moment, the "lightcurves" designation is enough to narrow any return list down to something reasonable, so I don't think there's a need from that point of view. And as was mentioned in our UMD meeting, typically the modifier for something like an occultation light curve would be in the product title - where it would be picked up by a text search for "occultation". So unless the subfacet values would supply new information or present a significant enhancement, I'd be inclined to let it wait until we have a specific problem to address.
Are there any astrometric data in SBN other than the ancient IHW astrometry? Hardly anyone would think of coming to SBN for astrometric data - they would go to MPC or JPL.