TimeSeries of positions (Asteroid)

Rob Seaman seaman at lpl.arizona.edu
Fri Nov 23 15:35:43 CET 2018

Hello all,

Not sure which of these lists I'm still subscribed to, but copying all
from the original message. Solar system science cases are the poster
child for the various features of STC supporting the near-field.
Hopefully IVOA is still embracing the full richness of space-time

One wonders if IVOA has engaged with the planetary science community
(our solar system or others) regarding these use cases? This applies
both to requirements discovery as well as a concept of operations and
ultimate uptake in support of this community.

Some context and links: A reminder that IVOA is first and foremost an
IAU activity under Commission B2. Solar system issues fall under several
commissions, e.g., ephemerides under Comm X2. The IAU has a recent
standard for small bodies astrometry / photometry:

  * https://github.com/IAU-ADES/ADES-Master

There are the usual debates about JSON vs XML, etc. The long time center
for such activities, the Minor Planet Center:

  * https://www.minorplanetcenter.net

was recently reorganized under the Small Bodies Node of the Planetary
Data System. If the IVOA is not coordinating with the PDS it should be,
both under the SBN and other nodes:

  * https://pds-smallbodies.astro.umd.edu

The Planetary Science community has the advantage of being able to send
spacecraft to visit its objects of study, and these are supported by
diverse activities at NASA centers, in particular JPL and GSFC, e.g.:

  * https://naif.jpl.nasa.gov/naif/
  * https://ssd.jpl.nasa.gov/?horizons
  * https://svs.gsfc.nasa.gov

For NEOs this includes:

  * https://cneos.jpl.nasa.gov

With other external groups like:

  * https://newton.spacedys.com
  * http://asteroid.lowell.edu

The community database of asteroid time series is explicitly curated at:

  * http://www.minorplanet.info/lightcurvedatabase.html

This would be a good site to scavenge science requirements. Various
familiar and unfamiliar archive sites support different solar system
data sets that should be of interest to IVOA. Many sites are in states
of active development.

There are meetings that IVOA should participate in to engage with the
Planetary Science community:

  * https://aas.org/meetings/dps50
  * https://astrogeology.usgs.gov/groups/planetary-data-workshop 
    (somewhat similar to ADASS)
  * https://www.lpi.usra.edu/planetary_news/2017/03/21/2018-planetary-science-informatics-and-data-analytics-conference/
  * http://hotwireduniverse.org

At the recent DPS there were booths for ADS and WWT, but I didn't notice
an IVOA presence. Apologies if this was an oversight on my part. The
Hotwired meetings started as a joint series between VOEvent and the
Heterogeneous Telescope Networks consortium and continues now under the
IAU Time Domain Working Group (and the AAS WG-TDA, as well). HTN is now
spearheaded by the bricks-and-mortar Las Cumbres Observatory. Several
from the VOEvent WG continue to be involved, but an enhanced IVOA
participation would be welcome in 2019! Moving objects in the solar
system have been a topic since the first meeting, but especially since
Hotwired V.

The main belt asteroids are foreground to celestial transients, but are
background to NEOs. IVOA use cases will always need to accommodate the
multiple spatial regimes, and this will have implications for time
standards, protocols, and infrastructure. This includes interesting
variations like Kuiper Belt Objects and artificial satellites / orbital

Rob Seaman, Lunar and Planetary Laboratory


On 11/23/18 2:53 AM, François Bonnarel wrote:
> Hi,
> This email sent yesterday to the three lists was apparently not sent
> to voevent. (Time domain maling list). I was apaprently not registered
> there.
> For those on several lists, sorry for the SPAM
> Cheers
> François
> -------- Message transféré --------
> Sujet : 	TimeSeries of position (Asteroid)
> Date : 	Thu, 22 Nov 2018 21:51:19 +0100
> De : 	François Bonnarel <francois.bonnarel at astro.unistra.fr>
> Pour : 	dm at ivoa.net <dm at ivoa.net>, <dal at ivoa.net> <dal at ivoa.net>,
> voevent at ivoa.net
> Der Dave, all,*
> Before interop Dave asked me to provide how a TimeSeries of Asteroid 
> could look like with the current ts model proposal and Utypes serialisation.
>> Someone recently described to me a use case that I haven't seen in our 
>>  discussions.
>>  To help me understand how to use the new model, could you send me a 
>>  simple example of how a time series of position over time would look ?
>>  For a single moving object we would get multiple ra/dec or Point 
>>  values plotted against time.
>>  For a mode complex example, multiple position and magnitude values 
>>  plotted against time.
> You can find a "dummy example" of this at this URL :
> http://volute.g-vo.org/svn/trunk/projects/time-domain/time-series/note/DATA/Proposed_Serializations/UTYPES/AsteroidSimple.xml
> Could be from gaia for an Asteroid.
> Then Dave gave more details for the second more complex example
>> Two use cases from the Gaia meeting.
>>  Exoplanets, the star will change both brightness and position by tiny 
>> amounts linked to the planet's orbit. Very small and slow changes in 
>>  both position and brightness, hard to detect above the noise.
>>  Near earth asteroid will be travelling very fast, and change 
>>  brightness in response to distance from the sun, position relative to 
>>  the sun, and rotation and shape of the asteroid itself. Very large and 
>>  rapid changes in both position and brightness.
>>  Both are valid cases for time series of positions and magnitudes. 
> This is an attempt for a Near Earth Asteroid
> http://volute.g-vo.org/svn/trunk/projects/time-domain/time-series/note/DATA/Proposed_Serializations/UTYPES/AsteroidFull.xml
> Data are dummy of course. but with about 1 magnitude amplitude and 1deg position change in 10 days !!!
> /*Changes for the Exoplanets use case can be easilly done :*/
> There will be no real "look and feel" change for the magnitudes.
> For position, the best is probably to set the mid position of the star in the refPOsition of COOSYS (see note below)  and to have the lon and lat columns giving the deviation from this
>  position along the ra and dec axes (and no more ecliptic longitude and latitude). The unit for these two columns will probbaly be "mas" instead of "deg". 
> Cheers
> François
> COOSYS note : currently there is no "refPosition" attribute in COOSYS. We propose to add one , taking the opportunity of the change in VOTable schema required to introduce TIMESYS. 
> this attribute allows accurate distinctions of positions computed from BARYCENTER, TOPOCENTER, GEOCENTER, as well as definitions of standalone  "local" spatial frames to code   for
>  very accurate  measurements.
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