Search Publications
The neutron star mass and radius of Aql X‑1 from quiescent X‑ray emissions
Li, Z.; Luo, Y.
We report the quiescent spectra of neutron star (NS) in Aql X‑1 from XMM‑Newton and Chandra. The NS atmosphere model, NSATMOS, is applied to fit the quiescent spectra. The Monte Carlo Markov Chain algorithm is used to constrain the NS mass and radius in Aql X‑1. We find that the absolute flux calibration between XMM‑Newton and Chandra for Aql X‑1 …
Observation, Modern Light-curve Analysis, and 89 yr Period Study of the Short-period Algol, AE Cassiopeia
Caton, Daniel B.; Samec, Ronald G.; Chamberlain, Heather +1 more
AE Cas was observed some 40 yr ago by Srivastava & Kandpal and was analyzed by Kopal’s Fourier frequency -domain technique. No further precision observations have taken place until the present study, which represents the first modern synthetic analysis of light curves using the 2016 version of the Wilson-Devinney (W-D) Program. It was observed…
The Evolutionary Status of GK Subgiants
Abt, Helmut A.
Snowden & Young suggested that the reason why there are GK subgiants is because they are members of binaries, which would bring them above the main sequence in an Hertzsprung-Russell (HR) diagram. They studied a sample of 30 G0-K1 IV stars and were disappointed to find only two to be spectroscopic binaries. With more accurate radial velocities…
Angular resolution of HD, HIP and DM catalogues
Malkov, O. Yu.
We estimate angular resolution of HD, HIP and BD/CD/CpD catalogues and discuss problems of cross-identification of components of visual binary stars with these catalogues.
Probing the Bardeen-Petterson Effect in Tidal Disruption Events with Spectral line Reverberation Mapping
Dovčiak, Michal; Zhang, Wenda; Karas, Vladimír +1 more
For an inclined accretion flow around a rotating black hole, the combined effect of the Lense-Thirring precession and viscous torque tends to align the inner part of the flow with the black hole spin, leading to the formation of a warped disk, known as the Bardeen-Petterson (BP) effect. In tidal disruption events (TDEs) in which a supermassive bla…
Optical performance of the Metis coronagraph on the Solar Orbiter ESA mission
Susino, Roberto; Antonucci, Ester; Fineschi, Silvano +19 more
The Metis coronagraph aboard the Solar Orbiter ESA spacecraft is expected to provide new insights into the solar dynamics. In detail, it is designed to address three main questions: the energy deposition mechanism at the poles (where the fast wind is originated), the source of the slow wind at lower altitude, and how the global corona evolves, in …
Search for new variable stars in the northern sky
Tautvaišienė, G.; Drazdauskas, A.; Mikolaitis, Š. +5 more
With the aim to find and characterize new variable stars, we obtained 24 470 CCD images in 13 fields of 0.4 square degrees with a 35/51 cm Maksutov-type semi-robotic telescope at the Molėtai Astronomical Observatory of Vilnius University. From photometric time series of 3604 stars analysed, we found 11 periodic variable stars and 70 slowly varying…
Surface Photometry of Proplyds in the Vicinity of θ 1 Ori C
Ismailov, N. Z.; Mamedkhanova, G. B.
Results of studies of the surface-brightness distributions of a group of young stellar objects located within 16″ of the star θ 1 Ori C are presented. Isophotes around each proplyd are constructed using violet, red, and near-infrared images. No regularity in the sizes of the diametral cross sections of the proplyds in the various photom…
Energetic Electron Patterns in the New SLS5 Longitude System
Mitchell, D. G.; Carbary, J. F.; Ye, Shengyi
Energetic electron (110-300 keV) fluxes collected during the entire 13-year Cassini mission are organized in the new Saturn longitude system (SLS5). This system is based on Saturn radio emissions, varies slowly in time and has a north and a south branch. When the fluxes are organized in SLS5 longitudes and magnetodisk coordinates, they display an …
High-mass Star Formation towards the southern infrared Bubble S10
Vig, S.; Ghosh, S. K.; Ishwara-Chandra, C. H. +2 more
We present a multi-wavelength analysis of the southern infrared bubble S10. Radio continuum emission is detected towards the bubble at 610 and 1280 MHz, and the bubble is estimated to be powered by massive stars of spectral type B0.5 - B0. A Class I/II type source, with an estimated mass of 6.2 Msol, lies 7'' from the radio peak. Six massive clump…