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A Search for Low-amplitude Periodic Brightness Variations in HD 168 443
Bondar', N. I.; Shlyapnikov, A. A.
The paper presents the results of studying light curves of the star HD 168443 obtained from the ground-based and space photometric observations within the ASAS, KWS surveys, and the Hipparcos mission from 1990 to 2020. During 30 years of observations, the average annual brightness of the star remained constant within the measurement errors, the me…
Two dynamically discovered compact object candidate binary systems from LAMOST low-resolution survey
Gu, Wei-Min; Yi, Tuan; Zhang, Zhi-Xiang +3 more
We report two binary systems, LAMOST J035540 + 381550 (hereafter J035540) and LAMOST J035916 + 400732 (hereafter J035916), identified through the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) low-resolution survey (LRS). Each of these two systems contains an M-type star orbiting with a invisible compact object candidate. Follo…
Light Curves and Period Analysis of Beta Lyrae Stars
Mennickent, R. E.; Garcés, J.; Cortés, C. C. +1 more
We present the light-curve period analysis of 36 Beta Lyrae stars from the OMC Archive. We check the reference period of the sample by applying the phase dispersion minimization periodogram. From our research, we determine the orbital period of five stars in the sample. One of them is CP Psc, showing a prominent hump in the light curve before the …
Investigation and cartographic representation of Hyperion space images photogrammetric processing results
Nadezhdina, I. E.; Sokolov, A. I.; Nyrtsov, M. V. +1 more
In this paper a new body-fixed coordinate system, based on the results of the processing of saturnian satellite Hyperion surface data, obtained by the Cassini spacecraft and proving the chaotic nature of this satellite rotation, was constructed. In this coordinate system, an approximating triaxial ellipsoid is defined, as well as global orthomosai…
HD 21520 b: a warm sub-Neptune transiting a bright G dwarf
Hellier, Coel; Latham, David W.; Littlefield, Colin +49 more
We report the discovery and validation of HD 21520 b, a transiting planet found with Transiting Exoplanet Survey Satellite and orbiting a bright G dwarf (V = 9.2,
CO outflows from young stars in the NGC2023 cluster
Güsten, R.; Mookerjea, B.; Sandell, G.
Context. Young early-type HAeBe stars are still embedded in the molecular clouds in which they formed. They illuminate reflection nebulae, which shape the surrounding molecular cloud and may trigger star formation. They are therefore ideal places to search for ongoing star formation activity.
Aims: NGC 2023 is illuminated by the Herbig Be sta…
Earth's Ionospheric Response to Solar Activity Phenomena in February-March 2023
Sheiner, O. A.; Vybornov, F. I.
As a result of the analysis of data from vertical and oblique sounding of the ionosphere in February-March 2023 using the new ionospheric index, it was found that solar coronal mass ejections (CMEs) of the loop type lead to a long-term decrease in the critical frequencies F-layer of the ionosphere, while other types of CMEs may not lead to signifi…
Coma and tail of Comet 67P/Churyumov-Gerasimenko during the 2021-2022 apparition
Lara, Luisa; Gray, Zuri; Bagnulo, Stefano +1 more
We present results on the global activity of comet 67P/Churyumov-Gerasimenko (67P), the ROSETTA target, during its first perihelion passage after the mission and after an encounter with planet Jupiter. 67P was observed by broad-band filter imaging at 33 epochs during 2021 May 21 to 2022 June 1. The mean radial flux profiles suggest that 'equilibri…
2017 Outburst of H 1743–322: AstroSat and Swift View
Dewangan, G. C.; Chand, Swadesh; Tripathi, Prakash +4 more
We perform a comprehensive timing and broadband spectral analysis using an AstroSat observation of the low-mass black hole X-ray binary H 1743–322 during its 2017 outburst. Additionally, we use two Swift/XRT observations, one of which is simultaneous with AstroSat and the other taken three days earlier, for timing analysis. The hardness–intensity …
Thermal and kinetic coronal rain diagnostics with Mg II h & k lines
Oliver, R.; Kriginsky, M.
Aims: The aim of this work is to assess the temperature and velocity diagnostics of coronal rain clumps, as observed in the lines formed in the upper chromosphere.
Methods: We performed the temperature diagnostics using inversions of data from nine spectroscopic observations obtained with the IRIS spectrograph in the Mg II h & k line…