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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…
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…
New photometric analysis of hot Jupiter: WASP-135b
Erdem, Ahmet; Öztürk, Oğuz
We report photometric follow-up observations of WASP-135b obtained using the 1.23-m telescope at Calar Alto Observatory and 1.00-m telescope at TÜBİTAK National Observatory during the 2017 and 2018 observational seasons. Eight new transit light curves of WASP-135b were analyzed with JKTEBOP code. The ratio of the planet radius to radius of host st…
AB Andromedae - An overcontact eclipsing binary
Nelson, Robert H.
In an effort to resolve the discrepancy between two earlier studies, new radial velocity and photometric data have been obtained and analyzed by Roche modelling for AB Andromedae, an overcontact W-subtype eclipsing binary. The new values for the basic data, m1 = 0.60 (3) Mʘ, m2 = 1.14 (3) Mʘ, R1
Irregular emission cycles in the Oe star HD 60 848
Nazé, Yaël; Fló, Joan Guarro; Rauw, Gregor +2 more
We analyse the spectroscopic and photometric variability of the Oe star HD 60 848 over the last twenty five years. The spectra reveal recurrent, but irregular cycles of increased circumstellar emission lines. These cycles are highly asymmetric displaying a slow increase over about 6 years, followed by a fast decay within about 6 months. Our analys…
KIC 4762887: A near-contact binary or an ellipsoidal variable star?
Liu, Liang; Li, Xu-Zhi
KIC 4762887 is a variable star with a very small amplitude discovered by Kepler and show the EW-type light curve. We analyzed the light curve of KIC 4762887 by using the 2015 version of the Wilson-Devinney code. The results indicated that it is not a contact binary, maybe not even an eclipsing binary. We also modelled the light curve by the Fourie…