Planetology Group Modelling and ground observations

1. Planetology GroupModelling and ground observations Presentation to the Visiting Committee 26 November 2007

2. Valsecchi, Coradini and Carusi in Tucson, 1981, “Comets” meeting. The Planetology Group • Our group was born in 1969, with the Apollo 11 landing on the Moon. We have always worked on the major theoretical problems of planetary sciences, including: • Origin and evolution • Dynamics • Cratering and impacts • Sample analysis • Planetary Interiors • Interrelations among populations • In the last 20 years we have also developed a strong interest in space exploration and instrumentation, and are now involved, at the PI level, in all major Solar System space missions

3. International activity • The Planetology Group has reached many years ago a good international recognition. • This is testified by: • Memberships in the ESA Solar System Working Group • Presidencies of IAU Commissions and Working Groups • PI-ships for many space missions (see Capaccioni’s presentation) • Continuous presence in all major international committees • Consultancies to non-astrophysical bodies (EU, UNO, OECD) • Editorships of Planetary Science Journals

4. Theoretical modelling: 1) Origin • Giant planets are a key element to understand the formation and the evolution of the Solar System. Main work lines on this subject are: • Specific formation processes of Giant Planets in our Solar System • Influence of physical conditions of the primordial Solar Nebula on the GP formation • When and where GP formed • Effect of the already formed planets on the other still accreting ones • How the specific scenario of formation and evolution of GP in our Solar System can be extended to other planetary systems • Why the satellite systems (and the rings systems) of the planets are so different

5. Theoretical modelling: 1) Origin (cont.ed) The group has developed several 3D hydrodynamical and N-body codes that follow the accretion of GPs and the dynamical evolution of a swarm of solid bodies under the action of the Sun, the viscous drag of the gas of the Solar Nebula and the presence of a number (one to four) of GPs. Density distribution of gas around Jupiter and Saturn in the final phases of their accretion (5 103 yr for Jupiter and 104 yr for Saturn)

6. Theoretical modelling: 2) Dynamics • Construction of an analytical theory to quantitatively model collision conditions and close encounters • Elaboration of a criterion to identify meteoroid streams using geocentric variables Comparison of analytical and numerical identification of keyholes on the b-plane of 2029 encounter of (99942) Apophis with the Earth • Improvements of existing algorithms for planetary, stellar, and galactic tidal perturbations on comets in the Oort cloud • Application to the circumterrestrial artificial debris population of impact probability algorithms developed for heliocentric orbits

7. Theoretical modelling: 3) Comet interiors • Theoretical models of the differentiation and thermal evolution of a nucleus are used to link observations with real nuclei characteristics and properties: • Understand compositions, structure and physical properties of comet nuclei • Understand physical phenomena inside comet nuclei • Foresee dust and gas fluxes, and percentage of active surface • Foresee surface and interior thermal characteristics

8. Theoretical modelling: 3) Comet interiors (cont.ed) Application of the model to comet Tempel 1 (Deep Impact target): Thermal map of the surface @1.5 AU Deep-Impact thermal map

9. Theoretical modelling: 4) NEOs • Several lines of research are devoted to the dynamics of NEOs and to the study of possible impacts with the Earth. • Numerical simulation of deflection in a variety of dynamical cases • Study of the influence of the Yarkovsky effect on impact predictions • Estimates of NEO populations derived from the results of current surveys • Continuous impact monitoring for newly discovered objects

10. Theoretical modelling: 4) NEOs (cont.ed) Investigation of the possible deflection of 99942 Apophis using kinetic energy. The plot shows the Delta V necessary to be delivered to the NEO in order to avoid the impact in 2036.

11. Ground observations: 1) Comets Three spectra of 9P/Tempel 1 close to the Deep Impact event. The line of oxygen is very well visible in all 3 spectra.

12. Ground observations: 2) NEOs • Observations of NEOs are performed at the Campo Imperatore Station of the Rome Observatory. They are intended to: • Discover new objects (the CINEOS Survey, see animation on the right) • Secure previous discoveries by follow-up ovbservations Comet 167P/CINEOS, discovered at Campo Imperatore, is the short period comet with the largest perihelion distance.

13. Support to The Spaceguard Central Node • The Spaceguard Central Node of the Spaceguard Foundation (SGF) is located at ESRIN (Frascati). It coordinates world-wide follow-up observations of NEOs. By contract between ESA, SGF and IASF, IASF personnel is in charge of: • Running the SCN on a daily basis • Providing Priority Lists and other support for observers around the world • Organizing international observing campaigns for relevant objects

14. Education and Outreach • University Course on Planetary Sciences, Roma 1 • Laurea and PhD students • Courses on Planetary Sciences in schools • Conferences for the general public • Interviews and participation to Radio and TV programs