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Cen X-3 as Seen by MAXI During Six Years
Torrejón, J. M.; Sanjurjo-Ferrín, G.; Rodes-Roca, J. J. +2 more
The aim of this work is to study both light curve and orbital phase spectroscopy of Cen X-3taking advantage of the MAXI/GSCobservation strategy. These studies allow delimiting the stellar wind properties and its interactions with the compact object. From the analysis of the light curve, we have estimated the orbital period of the binary system and…
Temperature Discrepancy with Photoionization Models of the Narrow-Line Region
Binette, L.; Villar Martín, M.; Magris C., G. +4 more
Using published work on the narrow-line region of Active Galactic Nuclei, a comparison is carried out among the [OIII] λ4363Å/5007Å ratios (ROIII) observed in quasars, Seyfert 2's and the spatially resolved ENLR plasma. Using the weak [ArIV] λ4711Å/λ4740Å doublet observed by Koski (1978) among Seyfert 2's, we find …
The Principal Astrophysical Parameters of the Open Clusters Gulliver 18 and Gulliver 58 Determined Using Gaia EDR3 Data
Tadross, A. L.; Elhosseiny, E. G.
A photometric and astrometric study of the two open star clusters Gulliver 18 and Gulliver 58 was carried out for the first time using the early third data release of the Gaia space observatory (Gaia-EDR3). By studying the proper motions, parallaxes, and color-magnitude diagrams of the two clusters, we determined their actual cluster membership. T…
C,T1,T2: A Complementary Method to Detect Multiple Populations with the Washington Filter System
Geisler, D.; Villanova, S.; Frelijj, H. +1 more
In this research we test the ability of a three Washington filter combination, (C − T1) − (T1 − T2), compared with that of the traditional C − T1 color to find multiple populations on two globular clusters: NGC 7099 and NGC 1851, types I and II Globular clusters, respectively. Our improved photometry and…
The Hipparcos Pleiades Parallax Error is Also a Proper Motion Error
Makarov, V. V.
The mean parallax of the Pleiades open cluster from the Hipparcos catalog is larger than the true value by approximately 1 mas. The origin of this error, as well as a possible algorithm of correcting it, was proposed by Makarov (2002). The problem is reassessed using the more accurate Gaia data with a focus on the predicted correction to the Pleia…
A New Visit to the Variable Stars in M56 and its Colour-Magnitude Diagram Structure
Arellano Ferro, A.; Deras, D.; Yepez, M. A. +1 more
We present a VI CCD photometric study and a membership analysis of the globular cluster M56 (NGC 6779). This produced a CMD decontaminated from field stars, which enabled a better confrontation with theoretical isochrones, zero-age horizontal branches (ZAHB) and post-ZAHB evolutionary tracks. Post He-flash evolutionary models with a He-core mass o…
Photometric Analysis of Two K Spectral Type Contact Binary Systems
Aceves, H.; Michel, R.; Popov, V. +3 more
The first analysis of the light curves of contact binaries ROTSE J135349.8+305205 (CB1) and 1SWASP J150957.5‑115308 (CB2) using the Wilson-Devinney code is presented. Both binary systems are of the A-subtype with a shallow fill-out (20.8% and 15.8% respectively) and a difference in temperatures between the components of < 200 K. A mass-ratio of…
Precise Measurement of Orbital and Physical Parameters of Bright Detached Solar Analog Eclipsing Binaries
Çakırlı, Ö.; Kayhan, C.; Hoyman, B. +2 more
We combined photometry from the All Sky Automated Survey (ASAS) and the Transiting Exoplanet Survey Satellite (TESS) with high-resolution spectroscopy from the ESO public archive to obtain, for the first time, absolute physical and orbital parameters for six double-lined detached eclipsing binary systems with solar-type components. The atmospheric…
Study of an Intermediate Age Open Cluster IC 1434 Using Ground-Based Imaging and Gaia DR2 Astrometry
Bisht, D.; Hendy, Y. H. M.
We present a detailed photometric and kinematical analysis of the poorly studied open cluster IC 1434 using CCD VRI, APASS, and Gaia DR2 database for the first time. By determining the membership probability of stars we identify the 238 most probable members with a probability higher than 60% by using proper motion and parallax data as taken from …
X-Ray Flux and Spectral Variability of BL Lacertae Objects Mrk 421, Mrk 501, and 1ES1426+428 with Suzaku Satellite
Abdelbar, Ahmed M.; Beheary, M. M.; Saad, A. Ata +1 more
We present a detailed spectral study of Suzaku observations of three blazars (Mrk 421, Mrk 501, and 1ES1426+428). The X-ray properties of our sample are derived by extracting the BL Lacertae sample spectra, and fitted by five models. The fit was in the soft X-ray band (0.8 - 10.0 keV). These models give similar results. By comparing the fits from …