Department of Physics, University of Florida

Nicolas Iro

Department of Physics
University of Florida
PO Box 118440
Gainesville, FL 32611-8440	    
Tel: (352)392-7003 
iro@phys.ufl.edu
       

Extrasolar planets modeling

During my Ph.D. Thesis which I started in September 2001 and defended on January, 7th 2005, I developed a radiative transfer model for extrasolar giant planets based on a one-dimensional line-by-line radiative transfer code. This model provides thermal emission and stellar reflected spectra which can be used to:

1. optimize searches for spectral signatures from extrasolar planets ;
2. in case of success, interpret observed data in terms of composition, thermal structure, and cloud properties.

This work have been made in collaboration with Bruno Bézard (LESIA, Obs. Meudon, France) and Tristan Guillot (CASSIOPEE, Nice, france).

You can find more about my work in the My Thesis section.
You can also jump to my results page.

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Spectroscopy of extrasolar planets

In collaboration with A. Coustenis (LESIA, obs. de Meudon, France), C. Moutou (LAM, Marseille, France), M. Mayor and D. Queloz (Obs. de Genève, Switzerland), I searched for spectral signatures due to the planet in the spectra of the star HD209458 (Iro et al., 2004 ; Coustenis et al., 2006). We analyzed several on- and off-transit spectra of the planet obtained with VLT/UVES at high spectral resolution (R = 100000), covering the 0.33 — 0.67 μm region. We searched for signatures from ions and neutral molecules originating from the planet's exosphere occulting the primary star. We found possible signatures in some H₂O⁺ lines. The spectral ranges contained in our data include possible features of Fe, O I, CO⁺, … The data analysis is still in progress.

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CASSINI/CIRS data analysis and interpretation

My current work at the University of Florida, in collaboration with Katia Matcheva is to analyze the infrared spectra obtained by the CASSINI space mission, which provide a unique data source for searching for spacial and temporal seasonal variations of temperature and composition for the giant planets of the Solar system. More to come soon...

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Modeling of cometary formation

As a graduate student of the Ecole Doctorale d’Astronomie & Astrophysique d’Ile de France, my first research project (from May to September 2001 full time followed by about one year part-time) was the investigation of the formation of comets in the early solar nebula. This was done in collaboration with D. Gautier, D. Bockelee-Morvan, F. Hersant and J. I. Lunine at the LESIA, Observatoire de Paris-Meudon, France. I applied the statistical thermodynamics of clathrate hydrates formation to an evolutionary model of the nebula, taking into account experimental results of the formation of clathrate hydrates. One major result is that the observed depletion of N₂ with respect to CO in comets can be explained by their differential trapping in clathrate hydrates during the formation of the cometesimals (Iro et al., 2003).