http://hdl.handle.net/2248/2 Search the Channel search http://prints.iiap.res.in/simple-search http://hdl.handle.net/2248/6026 Title: Reddening and dust distribution around V348 SGR<br/><br/>Authors: Kameswara Rao, N; Nandy, K<br/><br/>Abstract: Radio and Brackett gamma observations indicate large value of reddening E(B - V) = 1.5 to the nebula surrounding V348 Sgr, where as the star appears to be reddened by only E(B - V) is approximately 0.4. The infrared observations both ground based and with IRAS show that there are two dust components present: the hot dust represented by a 600 K black body longward of 3.5 micron and another cool dust (100 K or less) black body. The hot dust extends to about 6 arcsec radius from the star. The cool dust component surrounds the nebula and probably is responsible for the high extinction in the nebula. A tilted hollow cylinder or a tilted disk with a cavity type structure seems to be needed to account for the lack of reddening toward the star. Similarities of the nebular and dust properties of V348 Sgr and R Cr B indicate that they are approaching the red giant stage for a second time. http://hdl.handle.net/2248/6025 Title: Multi-dimensional Radiative Transfer to Analyze Hanle Effect in Ca II K Line at 3933 Å<br/><br/>Authors: Anusha, L. S; Nagendra, K. N<br/><br/>Abstract: Radiative transfer (RT) studies of the linearly polarized spectrum of the Sun (the second solar spectrum) have generally focused on line formation, with an aim to understand the vertical structure of the solar atmosphere using one-dimensional (1D) model atmospheres. Modeling spatial structuring in the observations of the linearly polarized line profiles requires the solution of multi-dimensional (multi-D) polarized RT equation and a model solar atmosphere obtained by magnetohydrodynamical (MHD) simulations of the solar atmosphere. Our aim in this paper is to analyze the chromospheric resonance line Ca II K at 3933 Å using multi-D polarized RT with the Hanle effect and partial frequency redistribution (PRD) in line scattering. We use an atmosphere that is constructed by a two-dimensional snapshot of the three-dimensional MHD simulations of the solar photosphere, combined with columns of a 1D atmosphere in the chromosphere. This paper represents the first application of polarized multi-D RT to explore the chromospheric lines using multi-D MHD atmospheres, with PRD as the line scattering mechanism. We find that the horizontal inhomogeneities caused by MHD in the lower layers of the atmosphere are responsible for strong spatial inhomogeneities in the wings of the linear polarization profiles, while the use of horizontally homogeneous chromosphere (FALC) produces spatially homogeneous linear polarization in the line core. The introduction of different magnetic field configurations modifies the line core polarization through the Hanle effect and can cause spatial inhomogeneities in the line core. A comparison of our theoretical profiles with the observations of this line shows that the MHD structuring in the photosphere is sufficient to reproduce the line wings and in the line core, but only line center polarization can be reproduced using the Hanle effect. For a simultaneous modeling of the line wings and the line core (including the line center), MHD atmospheres with inhomogeneities in the chromosphere are required.<br/><br/>Description: Restricted Access http://hdl.handle.net/2248/6024 Title: Photometric observations of solar corona during total solar eclipse of October 24, 1995<br/><br/>Authors: Kumar, S. S; Sharma, P; Devgun, C. B<br/><br/>Abstract: Twenty pictures of solar corona were taken on October 24, 1995 from Bhind on the central line of totality, covering a wide range of exposure times a 500mm telephoto lens captured Images on 35mm film duly calibrated. This sequence has provided valuable intensity data during the solar minimum. These frames have been digitized, giving lsophotes beyond 1.5 solar radii. http://hdl.handle.net/2248/6023 Title: Observations on the Unusual States in the Normal Patterns of the Private Behavior During the Total Solar Eclipse<br/><br/>Authors: Parthasarathy, M. D; Kulkarni, A. G<br/><br/>Abstract: Systematically planned observations conclusively reveal that sudden and large natural changes in the ambient light conditions during a total solar eclipse for a few minutes, initiates and cause marked alterations in the normal behavior pattern of the primates. Observations on the individual as well the group dynamical behavior among the red-faced Bonnet monkeys and the black faced Hanuman Langurs in the thick forested area near Ankola in Uttara Kannada district of Karnataka during the total solar eclipse are reported here.