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A comprehensive investigation of the variable overcontact system EH Cancri
Nelson, Robert H.; Alton, Kevin B.; StÈ©pień, Kazimierz
Precise multi-color CCD-derived photometric data were obtained from EH Cnc at two sites during 2010, 2014 and 2018 wherein each epoch used a different instrument. This has provided a unique opportunity to investigate parameter uncertainty following Roche modeling of light curves optimized by differential corrections using the Wilson–Devinney code.…
Vilnius photometry and Gaia astrometry of Melotte 105
Bilir, Selçuk; Yontan, Talar; Canbay, Remziye +1 more
Archival Vilnius CCD photometric observations are presented for the heavily reddened star cluster Melotte 105, resulting in colour-magnitude diagrams and spectral class estimates. There is considerable lack of agreement between studies for reddening, age and distance for this cluster explaining why the archival data are being made available by thi…
The influence of the cometary particles dynamics on the activity of comets
Wesołowski, M.
The paper deals with the dynamics of particles which are on the surface of the cometary nucleus. The key point is to research the behavior of the particles as a result of local sublimation. Generally, we can describe three mechanisms related to the particles behavior. Relatively small particles (of the order of micrometers) are ejected into the at…
Waves propagation in network and inter-network bright points channels between the chromosphere and transition regions with IRIS observations
Zeighami, Sima; Tavabi, Ehsan; Amirkhanlou, Elnaz
The significance increase of the plasma temperature from the solar photosphere to the corona up to 1MK is still unresolved. One of the candidates for this issue is waves and instabilities in the solar plasma. It was suggested that the energy of these waves could heat the solar atmosphere to transition-region (TR) and corona. Despite many recent ki…
Quasar catalogue for the astrometric calibration of the forthcoming ILMT survey
Mathew, Blesson; Stalin, C. S.; Surdej, Jean +3 more
Quasars are ideal targets to use for astrometric calibration of large scale astronomical surveys as they have negligible proper motion and parallax. The forthcoming 4-m International Liquid Mirror Telescope (ILMT) will survey the sky that covers a width of about 27
The horizontal branch morphology of the globular cluster NGC 1261 using AstroSat
Rao, N. Kameswara; Subramaniam, Annapurni; Rani, Sharmila +2 more
We present the results obtained from the UV photometry of the globular cluster NGC 1261 using far-UV (FUV) and near-UV (NUV) images acquired with the Ultraviolet Imaging Telescope (UVIT) on-board the AstroSat satellite. We utilized the UVIT data combined with HST, GAIA, and ground-based optical photometric data to construct the different UV colour…
Characteristics of SEPs during solar cycles 21–24
Kumar, Raj; Pande, Bimal; Pande, Seema +1 more
The study of the solar energetic particle events (SEPs) and their association with solar flares and other activities are very crucial to understand the space weather. Keeping this in view, here we present the study of SEPs (intensity
A search for variable stars in the four open star clusters
Bisht, D.; Rangwal, Geeta; Yadav, R. K. S. +3 more
We present a CCD photometric survey for the search of variable stars in four open clusters namely Berkeley 69, King 5, King 7 and Berkeley 20. The time series observations were carried out for 1 and/or 2 nights for each of the clusters in the year 1998, which have led to identify nineteen variable stars in these clusters. Out of these 19 variable …
[Rb/Zr] ratio in Ba stars as a diagnostic of the companion AGB stellar mass
Shejeelammal, J.; Goswami, Aruna
Understanding nucleosynthesis in and evolution of asymptotic giant branch (AGB) stars is of primary importance as these stars are the main producers of some of the key elements in the Universe. They are the predominant sites for slow-neutron-capture nucleosynthesis (s-process). The exact physical conditions and nucleosynthetic processes occurring …