Search Publications
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…
Light-time effect detected in fourteen eclipsing binaries
Mašek, M.; Uhlař, R.; Zasche, P. +2 more
The available minima timings of 14 selected eclipsing binaries (V1297 Cas, HD 24105, KU Aur, GU CMa, GH Mon, AZ Vel, DI Lyn, DK Her, GQ Dra, V624 Her, V1134 Her, KIC 6187893, V1928 Aql, V2486 Cyg) were collected and analyzed. Using the automatic telescopes, surveys, and satellite data, we derived more than 2500 times of eclipses, accompanied with …
Photocenter Shift Effect in Double Stars of Gaia DR2 Database
Ling, J. F.; López Oriona, A.; Sánchez Sellero, C.
In order to check the performance of the Gaia satellite when detecting double stars, we attempted to discover a photocenter shift affecting Gaia's second data release (Gaia DR2). We analyzed data of bona-fide double stars from "Double and Multiple System Annex" catalog and matched them with the Gaia DR2 catalog. We tried to derive a relationship b…
Near-Gaussian distributions for modelling discrete stellar velocity data with heteroskedastic uncertainties
Evans, N. Wyn; Sanders, Jason L.
The velocity distributions of stellar tracers in general exhibit weak non-Gaussianity encoding information on the orbital composition of a galaxy and the underlying potential. The standard solution for measuring non-Gaussianity involves constructing a series expansion (e.g. the Gauss-Hermite series) that can produce regions of negative probability…
Rotational modulation and single g-mode pulsation in the B9pSi star HD 174356?
Ilyin, I.; Järvinen, S.; Niemczura, E. +19 more
Chemically peculiar (CP) stars of the upper main sequence are characterized by specific anomalies in the photospheric abundances of some chemical elements. The group of CP2 stars, which encompasses classical Ap and Bp stars, exhibits strictly periodic light, spectral, and spectropolarimetric variations that can be adequately explained by the model…
Gaia-assisted discovery of a detached low-ionisation BAL quasar with very large ejection velocities
Milvang-Jensen, B.; Fynbo, J. P. U.; Christensen, L. +10 more
We report on the discovery of a peculiar broad absorption line (BAL) quasar identified in our Gaia-assisted survey of red quasars. The systemic redshift of this quasar was difficult to establish because of the absence of conspicuous emission lines. Based on deep and broad BAL troughs of at least Si IV, C IV, and Al III, a redshift of z = 2.41 was …
The ISM local to the runaway star WR16
Noriega-Crespo, A.; Reynoso, E. M.; Cichowolski, S. +3 more
Massive stars leave their imprint on the interstellar medium as they radiate their energy and undergo episodes of mass ejection throughout their lives. In this paper, we analyse the case of the Wolf-Rayet star WR16 combining archival multiwavelength data with new molecular observations obtained with the Atacama Submillimeter Telescope Experiment (…
Spatial and Temporal Variability of the 365-nm Albedo of Venus Observed by the Camera on Board Venus Express
Schröder, S. E.; Kouyama, T.; Imamura, T. +4 more
We mapped the distribution of the 365-nm albedo of the Venus atmosphere over the years 2006-2014, using images acquired by the Venus Monitoring Camera (VMC) on board Venus Express. We selected all images with a global view of Venus to investigate how the albedo depends on longitude. Bertaux et al. (2016,
Optical and X-ray studies of three polars: RX J0859.1+0537, RX J0749.1-0549, and RX J0649.8-0737
Raj, Ashish; Pandey, J. C.; Singh, K. P. +3 more
We present optical photometric and spectroscopic observations, and an analysis of archival X-ray data of three polars: RX J0859.1+0537, RX J0749.1-0549, and RX J0649.8-0737. Optical light curves of these three polars reveal eclipse-like features that are deep, total, and variable in shape. The optical and X-ray modulations of RX J0859.1+0537, RX J…
X-ray properties of dwarf nova EY Cyg and the companion star using an XMM-Newton observation
Balman, Şölen; Nabizadeh, Armin
We present the X-ray analysis of dwarf nova EY Cyg using the 45 ks XMM-Newton observatory archival data obtained in quiescence. We find orbital modulations in X-rays. We simultaneously fitted EPIC pn, MOS1 and MOS2 data using a model for interstellar medium absorption (tbabs) and a multi-temperature plasma emission model with a power-law distribut…