Cometary Grains

<strong>Seminar of the School of Physical Sciences -------------------------------------------------</strong> <strong>Title: Cometary Grains</strong> <strong>Speaker:</strong> Asoke K. Sen (Assam University, Silchar) Date: <strong>May 18, 2016 </strong>(Wednesday) <strong>Abstract:</strong> Comets are being studied for last several decades using ground based telescopes , to understand their orbits, gas and dust contents and other dynamical properties. Since the comets are believed to contain the most pristine materials of our solar system out of which Sun and other planets were born some 4.6 billion years ago, the above studies help us to understand the origin and evolution of our solar system. The dust particles which are released from the comet nucleus, contain most of these pristine materials. These particles scatter the solar radiation and are responsible to give the comets a bright spectacular appearance. Such scattered radiations are studied through photometry and polarimetry by the ground based telescopes to understand the properties of cometary dust and also the scattering processes in general. In addition, in recent years a number spacecrafts had flown very close to some of the comets and made very interesting in situ measurements on cometary dusts. These spacecraft measurements, together with the ground based observations on cometary dusts are providing us now, new insights into the processes which led to the formation of the comets and other members of the solar system. Such findings from our recent studies on cometary dusts will be discussed.