Search Publications
Spectral Behavior of the Symbiotic Nova HM Sge in the Ultraviolet
Sanad, M. R.; Abdel-Sabour, M. A.
Ultraviolet observations of the symbiotic nova HM Sge were obtained from the International Ultraviolet Explorer (IUE) through the interval from 1980 - 1992. Three line profiles demonstrating the variations of some emission lines at different dates are presented. We determined the reddening of HM Sge from the 2200 Å absorption feature; the estimate…
Searching for exoplanets by HEPS II. detecting earth-like planets in habitable zone around planet hosts within 30 pc
Yang, Ming; Zhang, Hui; Zhou, Ji-Lin +4 more
HEPS (Habitable ExoPlanet Survey) is a planning astrometry satellite that aims to find Earth-like planets in the solar neighbourhood. In this paper, we selected 140 planet harboring stars within 30 pc of the solar system to be potential targets for HEPS. We calculate the detection probability of the planet in habitable zone (HZ) for each system us…
The long-term optical activity of the propellers AE Aquarii and AR Scorpii
Šimon, Vojtěch
This analysis of the long-term optical activity of the propellers AE Aqr and AR Sco uses data from the Catalina Real-time Transient Survey, DASCH, and AAVSO. The site and character of the emissions from the phenomena caused by the magnetic field of the white dwarf (WD) vary from system to system. The histogram of intensities of the ensemble of fla…
Radio Signature of a Distant behind-the-limb CME on 2017 September 6
Rucker, H. O.; Panchenko, M.; Konovalenko, A. A. +5 more
We discuss properties of a Type IV burst, which was observed on 2017 September 6, as a result of the powerful flare X 9.3. At decameter wavelengths this burst was observed by the radio telescopes STEREO A, URAN-2, and the Nancay Decameter Array at frequencies 5-35 MHz. This moving Type IV burst was associated with a coronal mass ejection (CME) pro…
Origin of the in-orbit instrumental background of the Hard X-ray Imager onboard Hitomi
Enoto, Teruaki; Yamaoka, Kazutaka; Fukazawa, Yasushi +43 more
Understanding and reducing in-orbit instrumental backgrounds are essential to achieving high sensitivity in hard x-ray astronomical observations. The observational data of the Hard X-ray Imager (HXI) onboard the Hitomi satellite provide useful information on the background components due to its multilayer configuration with different atomic number…
Prolonged Lifetime of the Transient Ionized Layer in the Martian Atmosphere Caused by Comet Siding Spring
Gurnett, D. A.; Halekas, J. S.; Morgan, D. D. +4 more
In October 2014, the close encounter between Mars and comet Siding Spring produced a transient ionized layer in the upper atmosphere composed primarily of Mg+ and Fe+ ions. The layer was detected by instruments on three spacecraft, including the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) on Mars Expre…
New Types of the Chromospheric Anemone Microflares: Case Study
Dumin, Yurii V.; Somov, Boris V.
Chromospheric anemone microflares (AMFs) are transient solar phenomena whose emission regions have a multi-ribbon configuration. As distinct from the so-called "atypical" solar flares, also possessing a few ribbons, the temporal and spatial scales of AMFs are a few times less, and the configuration of their ribbons is more specific (star-like). Th…
Photometric study of five kepler contact binaries
Liu, Liang; Li, Xu-Zhi
A lot of data in time domain were obtained by the Kepler mission, including many contact binaries. Long-term observation lets us obtain more information about the short time scale variation in their light curves or in their orbital periods. Unfortunately, the exposure time is too long (most of them are 30 minutes). Hence, many variations in light …
A survey of extended matter around chromospherically active binary systems
Karakuş, Osman; Ekmekçi, Fehmi
We present an analysis of colour excess (CE) observations for 13 chromospherically active binary systems, together with 27 inactive reference stars of similar spectral types and luminosity classes of the components of these 13 binaries. We used the observations which were made by Johnson-Cousins BVRcIc , 2MASS, and WISE photo…
The explosive life of massive binaries
Renzo, M.; Zapartas, E.
Massive stars are born predominantly as members of binary (or higher multiplicity) systems, and the presence of a companion can significantly alter their life and final fate. Therefore, any observed sample of massive stars or associated transients is likely to be significantly influenced by the effects of binarity. Here, we focus on the relationsh…