Related papers: Ceres' opposition effect observed by the Dawn fram…
Coronal Mass Ejections (CMEs) are subject to changes in their direction of propagation, tilt, and other properties. This is because CMEs interact with the ambient solar wind and other large-scale magnetic field structures. In this work, we…
This work aimed to find the relationship between quasars' optical variability and spectral features to reveal the regularity behind the random variation. It is known that quasar's FeII/Hbeta flux ratio and equivalent width of [OIII]5007 are…
We report the discovery of mid-infrared excess emission in the young object RZ Psc. The excess constitutes ~8% of its Lbol, and is well fit by a single 500K black-body implying a dust free region within 0.7AU for optically thick dust. The…
Z CMa is a binary system which consists of two young stars: A Herbig AeBe component "Z CMa NW" embedded in a dust cocoon and a less massive component "Z CMa SE", which is classified as a FU Orionis type star. Recently, the system showed the…
The behavior of an adaptive optics (AO) system for ground-based high contrast imaging (HCI) dictates the achievable contrast of the instrument. In conditions where the coherence time of the atmosphere is short compared to the speed of the…
In planetary science, surface roughness is regarded to be a measure of surface irregularity at small spatial scales, and causes the thermal-infrared beaming effect (i.e. re-radiation of absorbed sunlight back towards to the Sun). Typically,…
We observed Ceres at three epochs in 2015 November and 2017 September and October with ALMA 12-meter array and in 2017 October with the ALMA Compact Array (ACA), all at ~265 GHz continuum (wavelengths of ~1.1 mm) to map the temperatures of…
The planetary obliquity plays a significant role in determining physical properties of planetary surfaces and climate. As direct detection is constrained due to the present observation accuracy, kinetic theories are helpful to predict the…
We propose a new method to retrieve the optical depth of Martian aerosols (AOD) from OMEGA and CRISM hyperspectral imagery at a reference wavelength of 1 {\mu}m. Our method works even if the underlying surface is completely made of…
Altough both components of the bright eclipsing binary $\alpha$ Dra having been resolved using long baseline interferometry and the secondary component shown to contribute some 15\% of the total flux, a spectroscopic detection of the…
We present the results of spectroscopic observations of two eclipsing WR+OB-type systems - CQ Cep and CX Cep, performed in 2020-2023 with a low-resolution slit spectrograph TDS ($\lambda\lambda= 3660-7410$\AA, $R = 1300-2500$) on 2.5-m…
We present the binary model and the eclipse timing variations of the eclipsing binary RR Cae, which consists of a white dwarf eclipsed by an M-type dwarf companion. The multi-wavelength optical photometry from the Transiting Exoplanet…
We made optical observations of the Gegenschein using a liquid-nitrogen-cooled wide-field camera, Wide-field Imager of Zodiacal light with ARray Detector (WIZARD), between March 2003 and November 2006. We found a narrow brightness…
Before an exoplanet transit, atmospheric refraction bends light into the line of sight of an observer. The refracted light forms a stellar mirage, a distorted secondary image of the host star. I model this phenomenon and the resultant…
The NASA/Dawn mission has acquired an unprecedented amount of data from the surface of the dwarf planet Ceres, providing a thorough characterization of its surface composition. The current favorite compositional model includes a mixture of…
The Milky Way disk exhibits intricate orbit substructure of still-debated dynamical origin. The angle variables $(\theta_\phi,\theta_R)$ -- which are conjugates to the actions $(L_z,J_R)$, and describe a star's location along its orbit --…
Common envelope (CE) evolution, which is crucial in creating short period binaries and associated astrophysical events, can be constrained by reverse modeling of such binaries' formation histories. Through analysis of a sample of…
We have obtained high-resolution spectra of four eclipsing binary systems (FM Leo, NN Del, V963 Cen and AI Phe) with the view to gaining insight into the relative orientation of their stellar spin axes and orbital axes. The so called…
We investigate how the uncertainty on the Hubble constant (H_0) affects the uncertainty in the Equation of State (EOS) of Dark Energy and the total density of the Universe (Omega_tot). We use the approximate relations between the…
We present the detection of visible light from the planet TrES-2b, the darkest exoplanet currently known. By analysis of the orbital photometry from publicly available Kepler data (0.4-0.9 microns), we determine a day-night contrast…