Physics and Astrophysics of Dust II: Probe, Formation and Astrophysical Implications

September 2 – 5 , 2009

Venue:
Lab “B” Auditorium, VBO,
Vainu Bappu Observatory,
Indian Institute of Astrophysics, Kavalur,
Alangayam – 635 701.

First Circular

Tentative Schedule

Rationale

The existence of dust in the vast space between stars was known to astronomers for nearly 75 years. Dust is an important component of the universe, without which stars and galaxies would have evolved in a different way and planets and the life would not have formed. Cosmic dust plays a vital role in Astrophysics, Astrochemistry and Astro-biology. The physical and astrophysical aspects of the dust are needed to be understood well in order to address their role in Astrochemistry and in Astrobiology. To derive a comprehensive understanding of the phenomena associated with dust, it is important to bring the community who are working on observational astronomy, theoretical modeling, laboratory astrophysics and astrochemists together. A workshop on Physics and Astrophysics of dust was held at VBO from 22nd to 24th of February 2007. Many advances were made recently in this area and the fields associated with this which are needed to be discussed collectively to update our knowledge on cosmic dust. Hence, in continuation of previous workshop, it is proposed to have a second workshop on cosmic dust with extended topics for discussion on this forefront research topic on modern Astronomy.

Apart form interactions with the astrophysical community, the workshop aims to establish collaborative interdisciplinary research with workers in fields of physics, chemistry, metallurgy, applied mathematicians, chemical engineers. A major interest is to understand and interpret the existing astronomical data and to derive understanding from laboratory studies and connections with simulations through realistic models.

Particular attention will be paid, to attract researchers, both theorists and experimentalists from universities and colleges, and identify the areas of overlap with their on-going researches and chart out a long term goal to produce perceptible impact on the question dust in the universe. The workshop also will help essentially to understand the areas of overlap and encourage cross disciplinary activity. Attention must be drawn to the following aspects of the problem:

Tentative topics for discussion

1) Astronomical implication 1: Observation
a) Dust in the solar system: IDPs, GEMS; b) Dust in the circumstellar environment: dust shells around AGB stars, dust in protoplanetary nebulae, starforming reflection nebulae, dust in in the vicinity of young stars and protoplatetary disks; c) Dust in the ISM: extinction curve, 2175 feature,
Diffuse galactic radiation, Extended Red and Blue emission, Diffuse Interstellar Bands, Interstellar polarization, interstellar microwave radiation, grain alignment

2) Dust Probe: Absorption, emission and scattering processes by dust, Radiative transfer in a dusty medium. Light scattering as probe for the study of dust grain: Elements of light scattering , Rayleigh, Mie, geometrical optics approximations, Discrete Dipole and T matrix approaches to light scattering and their limits of validity; Computational schemes of calculations; Effects of porosity and irregular morphology of grain surfaces on light scattering studies, principles of ellipsometry and surface spectroscopy. (computational schemes will be demonstrated during the course of the school and will serve as demonstrative assignment to the participants).

3) Experimental studies of light scattering, laboratory studies of astronomical dust properties.

4) Formation and evolution of dust: Chemistry of dust formation (reaction kinetics of species formation), exploration of chemical species in dust, organic and inorganic dust components, solidification process, formation, destruction and contamination of dust grains ( bulk contamination and surface contamination), classical, small, and very small grain populations and their size distributions, MRN size distribution and its limitations, geometry and morphology of dust, different models of dust grain structure. Formation of crystalline structure

5) Grain dynamics: Charging of grains and dynamics of charged and uncharged grains in the presence of flows and temperature gradients, dynamics, alignment and rotation of grains in presence of flows and magnetic fields; Signatures of grain dynamics on light scattering studies. Heating and cooling by the dust, dust heating by photoelectric emission and chemical reaction. Importance of dust in mass loss process in evolved stars, and in thermal balance of the ionized nebulae, surface chemistry and the formation of key molecules like H2, methane, drift of very small grains by the diffuse interstellar radiation field.

6) Dust abundances and Galactic chemistry: Dust based and gas based abundances and the atomic abundance budget in the Galaxy, carbon crisis in the interstellar medium. Constrains on dust models posed by abundances, abundance distribution in the Galaxy and their correlation with dust properties .

7) Astrophysical implications II: Theory and models 2D and 3D radiative transfer in star forming reflection nebulae, circumstellar envelopes, dust models on planet formation, coupling between gas-dust-radiation Origin and carriers of DIBS, ERE, EBE, 2175A feature, PAH hypothesis and their presence in various astrophysical environment, presence of soot particles and fullerance in the space.

Coordinators: C. Muthu, S. Chatterjee (muthu(AT)iiap.res.in, chat(AT)iiap.res.in)

Local organizing committee:

• C. Muthu
• P. Anbazhagan
• F. Sutaria
• R. Banyal
• K. Kuppuswamy
• S. Rajendran

Confirmed Participants