6,218 research outputs found

    Magnetic fields in multiple bright-rimmed clouds in different directions of H ~II region IC1396 - II

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    Bright-rimmed clouds form on the edges of H II regions affected by the high energy radiation from a central ionizing source. The UV radiation from the ionizing source results in compression and ionization causing either cloud disruption or further star formation. In this work, we present R-band polarization measurements towards four bright-rimmed clouds, IC1396A, BRC 37, BRC 38, and BRC 39, located in the different directions of the H II region, Sh2-131, in order to map magnetic fields (B-fields) in the plane of the sky. These BRCs are illuminated by the O star HD206267 and present a range of projected on sky geometries. This provides an opportunity to understand the magnetized evolution of BRCs. The B-field geometries of the clouds deduced from the polarization data, after correction for foreground ISM contamination, are seen to be connected to the ambient B-fields on the large scale. They seem to play an important role in shaping the cloud IC1396A and BRC 37. BRCs 38 and 39 show a broader and snubber head morphology possibly due to the B-fields being aligned with incoming radiation as explained in the simulations. A good general agreement is noted on comparing our observational results with the simulations supporting the importance of B-fields in BRC evolution. This work is the first step towards systematic mapping the B-fields morphology in multiple BRCs in an expanding H II region, extending the work presented by Soam et al. (2017b).Comment: 13 pages, 8 figures, accepted for publication in MNRA

    Genetic diversity analysis in Gladiolus genotypes (Gladiolus hybridus Hort)

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    In the present investigation, thirty gladiolus (Gladiolus hybridus Hort) genotypes were assessed to know the nature and magnitude of genetic divergence using Mahalanobis D2 statistics. Genetic diversity study indicated that among the 17 characters, most of the flower characters contributed towards diversity. Floret diameter contributed maximum towards genetic divergence followed by number of florets per spike, vase life, spike length and plant height.Thirty genotypes were grouped into 8 clusters and among them, cluster I was the largest with 9 genotypes followed by cluster II having 7 genotypes, and IV cluster 6 and cluster III with 3 genotypes each. Clusters were of V, VII and VIII solitary type means they having only one genotype in their group. Divergence values (D2 value) ranged from zero to 7.97 indicating considerable amount of moderate variability in the material studied. Information generated from the present study would be useful in selection of parents for future breeding programme for flower quality improvement in gladiolus. It is desirable to select genotypes from clusters having high cluster means and also with high flower character like spike length as parents for future recombination breeding programmes
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