Search Publications
Solar wind turbulence: Connections with energetic particles
Oughton, Sean; Engelbrecht, N. Eugene
For the solar wind, a wealth of observational evidence indicates that turbulence is an important dynamical process for velocity (v), magnetic (b), and other related fluctuations at MHD (fluid) scales. Here we review such observations and turbulence features, including discussion of when wave or turbulence descriptions can (or cannot) explain the o…
BO Ari Light Curve Analysis using Ground-Based and TESS Data
Poro, Atila; Rezaei, Samaneh; Aksaker, Nazim +4 more
We present new BVR band photometric light curves of BO Aries obtained in 2020 and combined them with the Transiting Exoplanet Survey Satellite (TESS) light curves. We obtained times of minima based on Gaussian and Cauchy distributions and then applied the Monte Carlo Markov Chain (MCMC) method to measure the amount of uncertainty from our CCD phot…
The first light curve solutions and period study of two contact binary systems: V1370 Tau and QQ Boo
Davoudi, Fatemeh; Poro, Atila; Rahimi, Jabar +7 more
The first light curve solutions of the binary systems V1370 Tau and QQ Boo are presented. The periodic changes are calculated, and a new ephemeris presented for each of these two binary systems. O-C analysis is performed using the MCMC method in OCFit code. The changing rate of period was measured as dP/dt= 0.2423 days/year for V1370 Tau and dP/dt…
An association of CMEs with solar flares detected by Fermi γ-ray burst monitor during solar cycle 24
Abdel-Sattar, Walid; Mawad, Ramy; Farid, Hussein M.
By performing certain spatial and temporal criteria, we obtained 492 CME events simultaneously associated with GBM solar flare events (hereafter, GBM-flare-CME) from the total number 5123 Gamma-ray Burst Monitor (GBM) solar flares and 15228 Coronal Mass Ejections (CMEs) detected during the solar cycle 24 (2008-2019). Among these 492 events, which …
A new approximate coupling function: The case of Forbush decreases
Xaplanteris, L.; Livada, M.; Mavromichalaki, H. +1 more
We attempt the derivation of a new coupling function between ground level and primary cosmic rays for the case of Forbush decreases. The calculations for the new function are based on basic Quantum Field Theory theoretical tools, something that has not been attempted till now in other widely used cosmic ray coupling functions. The use of Quantum F…
The destruction of the cometary nucleus - The case of 73P/Schwassmann-Wachmann
Wesołowski, M.
The paper presents an analysis of the actual brightness change of comet 73P/Schwassmann-Wachmann, which took place in 1995. The consequence of a cometary outburst is the destruction of a fragment of its surface. This causes the emission of comet material from both the surface and from exposed subsurface layers. Therefore, the calculations take int…
Absolute parameters of the W UMa binaries CSS J223614+311343, V523 Aur and V783 And
Michel, Raul; Kjurkchieva, Diana; Popov, Velimir A. +3 more
Photometric BVRc observations of the stars CSS J223614+311343, V523 Aur and V783 And were carried out and their absolute parameters (masses, radii and luminosities) were determined based on light curve modeling and Gaia distances. The main results are: (i) The components of CSS J223614+311343 and V783 And are of K spectral type while th…
BVR photometric study and absolute parameters of the eclipsing binary AG LMi
Ebadi, H.; Mousavi-Sadr, M.
We present the CCD observations and light and radial velocity curves analysis for the eclipsing binary system AG LMi. Three minimum times of light curves were determined and used to calculate the orbital period's value as 1.3590 ±0.0001 days and a new epoch of the system as 2458141.2040 ±0.0002 days. The observed B, V, and R light curves and radia…
A time-series VI study of the variable stars of the globular cluster NGC 6397
Arellano Ferro, A.; Calderón, J. H.; Lázaro, C. +4 more
We present a new time-series VI CCD photometry of the globular cluster NGC 6397, from which we obtained and analysed the light curves of 35 variables carefully identified in the cluster field. We assessed the membership of the variables with an astrometric analysis based on Gaia DR2 data. The cluster colour-magnitude diagram was differentially der…
The study of runaway candidate stars in the 30 Doradus region: Using Gaia DR2 data
Gebrehiwot, Yikdem Mengesha; Teklehaimanot, Berhe Tewelde
We explore the Gaia DR2 relative proper motions of seven young, massive, OB type runaway candidate stars presented by Platais et al. (2018) in the 30 Doradus (30 Dor) region of the Large Magellanic Cloud (LMC). The stars are slow runaways in the tangential plane of the 30 Dor region with relative proper motions µ ≤ 0.4 mas yr-1 th…