Abstract Details
| Name: Ayesha Maryam Mazarbhuiya Affiliation: Ph.D Scholar, Assam Universuty Conference ID: ASI2018_793 Title : Polarimetric study of comet C/2015 V2 (Johnson) at low phase angle Authors and Co-Authors : Prithish Halder(Assam University, Silchar), Himadri Sekhar Das(Assam University) and Biman J. Medhi(Aryabhatta Research Institute of Observational Sciences,Nainital) Abstract Type : Contributed Talk Abstract Category : Sun and the Solar System Abstract : The optical polarimetric observation of comet C/2015 V2 (Johnson) was performed at low phase angle 21.6o using the 1.04-m Sampurnanand telescope of ARIES near Nainital in India on 30th December 2016 by using R photometric band (λ= 630 nm, Δλ=120 nm). We have estimated the average degree of polarization of this comet to be -0.686% at phase angle 21.6o. This result is found to be consistent with other observed comets at this phase angle. The variation of polarization value with the increase of aperture radius from the photocenter has been observed which suggests that the physical properties of the cometary dust of C/2015 V2 (Johnson) differ in both inner and outer region. On the increase of the aperture radius, negative polarization decreases gradually. Also, the decrease in intensity with a gradual increase in distance from the photocenter is being well observed in both the solar and antisolar directions which indicates the variation in dust distribution (as well as the variation/knowledge of physical properties of dust grain) in due times. The intensity is higher in the solar direction as compared to the antisolar direction, and a diffuse coma is observed in the antisolar direction which is due to the sublimation of ice and rocks by solar radiation pressure. The study of negative polarisation at low phase angle gives the idea of the composition feature of the comet which is useful in cometary science. Keywords: negative polarization - cometary dust - diffuse coma. |