Related papers: Physical Parameters of the Visually Close Binary S…
ASAS photometric observations of LS 1135, an O-type SB1 binary system with an orbital period of 2.7 days, show that the system is also eclipsing. This prompted us to re-examine the spectra used in the previously published spectroscopic…
In the era of astronomical big data, more than one million contact binaries have been discovered. Traditional approaches of light curve analysis are inadequate for investigating such an extensive number of systems. This paper builds on…
We present a new library of synthetic spectra based on the stellar atmosphere code PHOENIX. It covers the wavelength range from 500{\AA} to 55000{\AA} with a resolution of R=500000 in the optical and near IR, R=100000 in the IR and…
This study presented the first light curve analysis of the OP Boo and V0511 Cam binary stars, which was conducted in the frame of the Binary Systems of South and North (BSN) Project. Photometric ground-based observations were conducted with…
Understanding the atmospheric parameters of stars on the top of the RGB is essential to reveal the chemical composition of the Milky Way, as they can be used to probe the farthest parts of our Galaxy. Our goal is to determine the chemical…
The young binary system HD 350731 is a noteworthy laboratory for studying early-type binaries with similar components. We present here the analysis of differential multi-color photometric and spectroscopic observations for the double-lined…
Radial velocity measurements and simple sine-curve fits to the orbital velocity variations are presented for the third set of ten contact binary systems: CN And, HV Aqr, AO Cam, YY CrB, FU Dra, RZ Dra, UX Eri, RT LMi, V753 Mon, OU Ser. All…
The recently discovered eclipsing binary system TYC 2675-663-1 is a X-ray source, and shows properties in the optical that are similar to the W UMa systems, but are somewhat unusual compared to what is seen in other contact binary systems.…
Recently, Gauza et al. (2015) reported the discovery of a companion to the late M-dwarf, VHS J125601.92-125723.9 (VHS 1256-1257). The companion's absolute photometry suggests its mass and atmosphere are similar to the HR 8799 planets.…
$Aims.$ We present a database of 43,340 atmospheric models ($\sim$80,000 models at the conclusion of the project) for stars with stellar masses between 9 and 120 $M_{\odot}$, covering the region of the OB main-sequence and Wolf-Rayet (W-R)…
Recent observations revealed loop-like structures at very small scales visible in observables that sample transition region (TR) and coronal temperatures. Their formation remains unclear. We study an example of a bipolar system in realistic…
We present orbital elements and mass sums for eighteen visual binary stars of spectral types B to K (five of which are new orbits) with periods ranging from 20 to more than 500 yr. For two double-line spectroscopic binaries with no previous…
We present analysis of optical photometric and polarimetric observations of contact binary system FO Hydra (FO Hya). The computed period of the system is 0.469556+/-0.000003 days. An O-C curve analysis indicates an increase in its period by…
We model the spectra and spectral energy distribution of V838 Mon which were observed in February, March, and November, 2002. Theoretical spectra are calculated using the classical model atmospheres taking into account absorption of atomic…
We report on a comparison of spectroscopic analyses for hydrogen (DA) and helium atmosphere (DB) white dwarfs with Gaia Data Release 2 (DR2) parallaxes and photometry. We assume a reddening law and a mass-radius relation to connect the…
Photometric observations in V and I bands and low-dispersion spectra of ten ultrashort-period binaries (NSVS 2175434, NSVS 2607629, NSVS 5038135, NSVS 8040227, NSVS 9747584, NSVS 4876238, ASAS 071829-0336.7, SWASP 074658.62+224448.5, NSVS…
Double-lined spectroscopic binaries which are also eclipsing provide the most accurate stellar data, and are consequently of first importance to improve stellar evolution modelling. While the mass and radius of each component of detached…
Aims: We simulate the spectra of massive binaries at different phases of the orbital cycle, accounting for the gravitational influence of the companion star on the shape and physical properties of the stellar surface. Methods: We used the…
Direct imaging studies have mainly used low-resolution spectroscopy ($R\sim20-100$) to study the atmospheres of giant exoplanets and brown dwarf companions, but the presence of clouds has often led to degeneracies in the retrieved…
We report spectroscopic observations of the star HIP 50796, previously considered (but later rejected) as a candidate member of the TW Hya association. Our measurements reveal it to be a single-lined binary with an orbital period of 570…