Search Publications
Revisiting the X-ray emission of the asynchronous polar V1432 Aql
Qian, Sheng-Bang; Zhu, Li-Ying; Wang, Qi-Shan
As the only eclipsing asynchronous polar, V1432 Aql provides an excellent laboratory to study the interaction between the accreted matter and the magnetic field. Here, we report an analysis of the X-ray data from the contemporaneous NuSTAR and Swift-XRT observations. The X-ray data present a profile with a low-intensity state for almost half an or…
Signatures of large-scale cold fronts in the optically-selected merging cluster HSC J085024+001536
Oguri, Masamune; Fujimoto, Ryuichi; Okabe, Nobuhiro +5 more
We represent a joint X-ray, weak-lensing, and optical analysis of the optically-selected merging cluster, HSC J085024+001536, from the Subaru HSC-SSP survey. Both the member galaxy density and the weak-lensing mass map show that the cluster is composed of south-east and north-west components. The two-dimensional weak-lensing analysis shows that th…
Research on the HIP 18856 binary system
Mitrofanova, Arina; Dyachenko, Vladimir; Beskakotov, Anatoly +5 more
The results of a study on the binary HIP 18856 and construction of its orbit are presented. New observational data were obtained at the BTA of SAO RAS in 2007-2019. Earlier, Cvetković et al. constructed the orbit for this system. However, it is based on six measurements, which cover a small part of the orbit. The positional parameters of the ESA a…
L199, A new variable star in M13
Violat-Bordonau, F.
During a routine study of the variable stars of Messier 13 (NGC 6205 = Cl 1639+365) we have discovered the variability of L199 (TYC 2588-1386-2), a red giant star member of the cluster: using the photometric data - in V band - obtained in the 2019 and 2020 campaigns we have verified its variability. Data from the Zwicky Transient Facility (ZTF) an…
Observations of the Bright Star in the Globular Cluster 47 Tucanae (NGC 104)
Benjamin, R. A.; Dupree, A.; Miller Bertolami, M. M. +3 more
The Bright Star in the globular cluster 47 Tucanae (NGC 104) is a post-asymptotic giant branch (post-AGB) star of spectral type B8 III. The ultraviolet spectra of late-B stars exhibit myriad absorption features, many due to species unobservable from the ground. The Bright Star thus represents a unique window into the chemistry of 47 Tuc. We have a…
UBVRI observations of the flickering of the dwarf nova RX And
Zamanov, R. K.; Nikolov, G.; Georgieva, A. T.
We report observations of the flickering variability of the dwarf nova RX And in five bands (UBVRI) on two nights. On 25 October 2019 the brightness of the star was B≈ 13.8 mag, the amplitude of the flickering was 0.47 mag, and we estimate for the flickering source temperature Tfl = 10700 ± 400 K, and radius Rfl =0.046 ± 0.00…
Independent Analysis of µδ Data of ILS and INDLS Catalogs to Obtain the Spin of the Bright Gaia DR2 Reference Frame
Aleksić, J.; Damljanović, G.; Stojanović, M.
The Gaia DR2 reference frame should be without relative rotation to the quasars (QSOs) and consistent with the International Celestial Reference System (ICRS). For the faint part of DR2 (stars with Gaia magnitude G≥16) that task was done via Gaia's observations of QSOs (G≥17 mag), but the bright DR2 (G≤13 mag) is difficult to validate and it rotat…
Constraints on Sub-Neptune Planet Candidate KOI-972.01 via Joint Variability/Gravity-darkening Analysis
Barnes, Jason W.; Myers, Samuel A.; Ahlers, John P.
We analyze Kepler photometry of transiting planet candidate KOI-972.01, accounting for both stellar variability and gravity darkening. KOI-972.01 stands out because of its small radius, less than that of Neptune, and because of its intermediate orbit period at 13.12 days, long enough to avoid significant tidal evolution, and thus it represents an …
Improving the Orbits of Four Visual Binaries Using Gaia DR2 Data and Observations with the 26-inch Refractor of Pulkovo Observatory
Romanenko, L. G.; Izmailov, I. S.
We use a modified method of the apparent motion parameters (AMP), in which the initial data from the Gaia DR2 catalog are not only high-precision coordinates, parallaxes, and radial velocities of the components of the studied wide binary stars, but are also their proper motions. The coincidence of the AMP orbits obtained both from the Gaia DR2 dat…
Oxygen-Rich Cool Stars in the Cepheus Region. New Spectroscopic Observations of Selected Objects from the KP2001 Catalog
Gigoyan, K. S.; Kostandyan, G. R.; Petrosyan, G. V. +1 more
Spectra taken with the 2.6-m telescope at the Byurakan Astrophysical Observatory (BAO) in the λλ4000-7250Å range for eight M giants from the KP2001 catalog confirm their oxygen-rich nature. The features of these spectra are examined. Several important physical parameters from the EDR3 Gaia data base are presented. The optical variability is studie…