Within the period of 1988-2003, Dr. I. Simonia has studied the dynamics of cometary atmospheres; luminescence of cometary ices; natural microstructure of iron meteorites; photochemical evolution of icy surfaces of planet satellites; and fluorescence of circumstellar dust.
Since 2004 he has been investigating unidentified cometary emissions, which are nearly always present in optical spectra of comets. He has showed that the mentioned unidentified emissions have photoluminescence nature. And the sources of these photoluminescent emissions are frozen hydrocarbon particles of icy cometary halo. I. Simonia was the first to suggest a physical model of frozen hydrocarbon particles and described their basic properties. He has investigated comets 122P/de Vico, 19P/Borrelly, 109P/Swift-Tutle, 23P/Brorsen-Metcalf, 153P/Ikeya-Zhang and showed that about 10% of unidentified emissions of spectra of these comets belong to photoluminescene of FHP. He has also showed that icy particles of 153P/Ikeya-Zhang comet are luminescent in UV range (ultra-violet luminescence of cometary FHP).
I.Simonia has developed new theory of the interplanetary nanodust. This theory introduces the hypothesis of existence of a hardly detectable component of the interplanetary dust cloud and demonstrates that such a component is a dust formation consisting of the dust particles of nano-metric dimentions. This theory describes also the main physical properties of such a kind of nanodust, and its possible chemical and mineralogical peculiarities proposes new explanations related to reddening of the dynamicaly cold transneptunian objects on account of scattering their light by nanodust of the hardly detectable component of the interplanetary dust cloud. The relation for the coefficient of absorption by the nanodust has been proposed.
I.Simonia also investigates circumstellar dust in the form of mineral and icy particles. He has elaborated the model of frozen hydrocarbon particles in the form of carbonaceous nucleus and icy mantle, consisting of frozen mixture of polycyclic aromatic hydrocarbons and n-alkanes.
Ultra-violet radiation excites photoluminescene of such particles in the form of lines and bands of optical spectrum. Emissions of such kind were found by him in the spectrum of nebula Ced 201 and interpreted as photoluminescence of circumstellar FHP. Through detection and further interpretation of these emissions it was managed to determine the physical properties and chemical composition of icy circumstellar particles. I. Simonia was the first to show that faint unidentified emissions of spectra of some post-AGB objects, including planetary nebula NGC 7027, have cathodoluminescent nature. The sources of these emissions are micro and nano grains of the diamond, as of a component of circumstellar dust. I. Simonia described the process of cathodoluminescence of circumstellar diamond dust and established some physical and chemical characteristics of these particles in the field of rigid electromagnetic and corpuscular radiation from the central stars.
I.Simonia has invented the method of luminescent microstructurography (Georgia, patent 404, 1996). This method enables to quickly reveal natural microstructure of surfaces of the solid bodies, such as meteorites, minerals, glass, stone, metal, and archaeological samples. He has used this method for investigation of iron meteorites microstructure.
Within the period of 1988-2003, I. Simonia has investigated some ancient astronomical materials and artifacts. In particular, he has investigated some old-Georgian astronomical manuscripts, including the manuscript “Star book”. He has shown that this manuscript of the XVIII century is a reference book of some kind of astronomical and astrological content. Within these years I. Simonia has studied also a general tendency of development of old-Georgian astronomical world outlook in the period of the XVI century BC – XVIII century AD. He has described functioning of Tiflis observatory of the XIX century. I. Simonia has also studied Western-European astronomical heritage. Sinece 2004 I.Simonia investigates astronomical significance of megalithic monuments.
Recently he prepared and published (with co-authors) an electronic book (database) “astronomical Manuscripts in Georgia.”
I. Simonia is the head of two PhD programs (molecular astrophysics and archaeoastronomy) at the School of Natural Sciences and Engineering of Ilia State University. He is the supervisor of several PhD students. He teaches courses in astronomy and related subjects.