Paris Astronomical Data Centre

Observatoire de Paris

Planetary Science

The Planetary Science theme of VO-Paris is organized around four main resources: the Encyclopedia of extra-solar planets, the SkyBoT service, APIS, and a system of data services interoperable through a protocol addressing the whole field of Planetary Science.

Extrasolar planets

The study of extrasolar planetary systems has become a very active field which will grow continuously in the coming years and decades. This new field of astronomy comprises two types of activities: observations and modeling. Observations are intended both to detect new planets and to refine our knowledge of these objects. Modeling is aiming at the theoretical understanding of the physical and dynamical processes acting on individual planets, planetary systems, and the interactions of the planets with their host stars.

An exhaustive on-line catalogue of extrasolar planets properties was established in the Observatory of Paris in February 1995, after the confirmation of the first planets around a pulsar. It is constantly updated to include all published properties of these objects.

In addition to the catalogue, the web interface provides an exhaustive bibliography and a list of conferences, plus several online tools of scientific interest, for instance to display cross-correlations between planetary and stellar characteristics. The catalogue is also accessible through VO mechanisms, so the data can be plotted and studied using standard VO applications such as TOPCAT.

SkyBoT / SSODnet

SkyBoT (Sky Body Tracker) is a VO tool to seek and identify solar System objects in astronomical images. It relies on a database of pre-computed ephemeris of all of the known solar system objects, which can be queried in many ways. SkyBoT is available directly from some VO tools, e.g. Aladin and Audela, and can be directly queried on line.

SSODnet is a project to connect external databases of small bodies of the solar System and provide them with a global VO interface. It currently provides a name resolver that allows the user to identify an object through its various denominations, or through its celestial coordinates at a given time.


APIS (Auroral Planetary Imaging and Spectroscopy) is a compilation of reprocessed HST images and spectra related to auroral phenomenas on giant planets.

Planetary aurorae are powerful emissions radiated from the auroral regions of magnetized planets by accelerated charged particles, in a wide range of wavelengths, from radio to X-rays. The UV range in particular is adapted to measure collisionaly excited transitions of H and H2, the dominant species in the upper atmosphere of giant planets, produced by precipitating auroral particles. It additionally benefits a good angular resolution.

Auroral UV observations therefore provide a wealth of informations on planetary atmospheres and magnetospheres. They also offer a unique diagnostic to remotely probe the solar wind activity throughout the heliosphere.

The APIS database is accessible from a dedicated web site or via VO requests, e. g., from the VESPA portal.


VESPA is an integrated system connecting many data services related to Planetary Science and solar Physics. The VESPA portal allows the user to query simultaneously these services, to identify data of interest from science-oriented parameters, and to plot and analyze data on line using standard techniques.

VESPA results from an R&D action conducted in the framework of the FP7 European program to define a science-driven access method to Planetary Science data in general. The resulting system relies heavily on the developments of the Astronomical Virtual Observatory (IVOA) and space agencies (IPDA), and is now maintained in the Europlanet 2020 programme, started Sept. 2015.

EPN-TAP is an access protocol based on the Table Access Protocol of the IVOA and on a general Data Model for Planetary Science. Data services are declared in the IVOA registries, are queried from the VESPA interface, and the results can be visualized using standard IVOA tools. In addition, the client also implements the PDAP protocol to query PDS data archives from ESA and Jaxa.

VESPA currently accesses the major Planetary Science data services at PADC, plus a number of small databases. It will be greatly expanded in the current Europlanet 2020 programme, and is expected to connect many new data services from European institutes. The VESPA activity of Europlanet 2020 gives support to data providers in order to set up small data services locally and make them available to the community through a powerfull data mining and visualization system.

Emerging services

New major data services are being developed, and are interfaced with VESPA :

- TNOs are cool is a compilation of observations of Trans-Neptunian Objects by the Herschel and Spitzer orbital observatories, plus selected published properties of TNOs.

- MASER is a set of services and tools related to radio observations of the solar System.

- SERPE (Simulation d’Emissions Radio Planétaires et Exoplanétaires) is a simulation tool to support planetary radio observations from ground-based or spaceborne instruments. The code has been designed in relation to the JUNO mission, due at Jupiter in 2016.

- VVEx provides access to observations of Venus by the VIRTIS instrument on Venus-Express. VESPA provides search functions on top of the ESA/PSA archive, and derived products will be included in the data service.