KUV 23182+1007 was identified as a blue object in the Kiso UV Survey in the 1980s. Classification-dispersion spectroscopy showed a featureless continuum except for a strong emission line in the region of He II 4686Å. This is a hallmark of the rare AM CVn class of cataclysmic variable star, so we have obtained a high-S/N blue spectrum of this object to check its classification. Instead, the spec...

High-precision light curves were extracted from TESScut images. Together with APOGEE and LAMOST medium resolution spectra, a joint study was made for six early K-type contact binary candidates selected unbiasedly orbital periods around 0.268 days. It is found that all of them (RV CVn, EK Com, V384 Ser, V1038 Her, EH CSS$\_$J125403.7+503945) are W-subtype shallow systems though different mass ra...

1SWASP J162545.15-043027.9 (WASP 1625-04) has been announced as one of EL CVn candidates showing total primary eclipses and ellipsoidal variations. This paper presents the absolute properties binary star, based on our high-resolution spectroscopy conducted from 2015 through 2020. From spectral analysis, radial velocities (RVs) for both components were obtained with effective temperature $T_{\rm...

We present UBV RI and uvby photometry of HD 81410 obtained on a total of 40 nights during 1987–90, and an analysis of its long-term photometric behaviour. The star is found to show two well-separated minima in its light curve most of the time; probably there are two preferred effective longitudes about which spots are mainly formed. The migration of the phase of the light minimum usually seen i...

This paper discusses two novel artificial neural network architectures applied to multi-class classification problems of remote-sensing data. These approaches are 1) a spiking-neural-network model for the partitioning of data into clusters, and 2) a neuron model based on complex-valued weights (CVN). In the former model, the learning process is based on the Spike Timing-Dependent Plasticity rul...

We present VLBI images of the RS CVn binary star HR 5110 (=BH CVn; HD 118216), obtained from observations made at 8.4 GHz on 1994 May 29/30 in support of the NASA/Stanford Gravity Probe B project. Our images show an emission region with a core-halo morphology. The core was 0.39 ± 0.09 mas (FWHM) in size, or 66%±20% of the 0.6 ±0.1 mas diameter of the chromospher-ically active K subgiant star in...