Search Publications
Solar and geomagnetic activity dependence of 150-km echoes observed by the Equatorial Atmosphere Radar in Indonesia
Yokoyama, Tatsuhiro; Takagi, Rieko; Yamamoto, Mamoru
The occurrence characteristics of 150-km echoes in low-latitude regions are studied using the Equatorial Atmosphere Radar (EAR) in Indonesia. The long-term observation of the 150-km echoes by the EAR enables us to study the occurrence characteristics of 150-km echoes statistically. It is shown that the occurrence rate of the 150-km echoes observed…
V608 Cassiopeiae: A W UMa-Type Eclipsing Binary with Two Possible Circumbinary Companions
Lee, Jae Woo; Park, Jang-Ho
We present the photometric properties of V608 Cas from detailed studies of light curves and eclipse timings. The light curve synthesis indicates that the eclipsing pair is an overcontact binary with parameters of ΔT = 155 K, q = 0.328, and f = 26%. We detected the third light ℓ_{3}, which corresponds to about 8% and 5% of the total systemic light …
Evidence of distant spiral arms in the Galactic disk quadrant IV from VVV red clump giants
Minniti, D.; Saito, R. K.; Alonso-García, J. +4 more
The discovery of new clear windows in the Galactic plane using the VVV near-IR extinction maps allows the study of the structure of the Milky Way (MW) disk. The ultimate goal of this work is to map the spiral arms in the far side of the MW, which is a relatively unexplored region of our Galaxy, using red clump (RC) giants as distance indicators. W…
Stark broadening effect in hot DA white dwarfs: Ultraviolet lines of Fe V
Hamdi, Rafik; Ben Nessib, Nabil; Sahal-Bréchot, Sylvie +1 more
Stark widths and shifts have been calculated for 17 ultraviolet lines of Fe V of astrophysical interest. The calculations have been made using semiclassical perturbation approach. The work is motivated by the importance of ultraviolet lines for the study of hot white dwarf atmospheres specially for investigations of the variation of fine structure…
Interface Region Imaging Spectrograph (IRIS) Observations of the Fractal Dimension in the Solar Atmosphere
Aschwanden, Markus J.; Vilangot Nhalil, Nived
While previous work explored the fractality and self-organized criticality (SOC) of flares and nanoflares in wavelengths emitted in the solar corona (such as in hard X-rays, soft X-rays, and EUV wavelenghts), we focus here on impulsive phenomena in the photosphere and transition region, as observed with the {\sl Interface Region Imaging Spectrogra…
Patterns of martian glacial deformation: Implications for glacio-geology, internal structure, and regional climate
Conway, Susan J.; Becerra, Patricio; Grau Galofre, Anna +2 more
Viscous Flow Features (VFF) are widespread in the martian mid-latitudes and indicative of near-surface ice deposits. Their distribution and morphology hint at the regional history of ice deposition and ablation, as well as changes in surface temperature. Here we interrogate the deformation history of a type of VFF, a Lobate Debris Apron (LDA), loc…
The impact hazard of near-Sun comets
Neslušan, Luboš; Tomko, Dušan
There are several groups of comets with perihelion near the solar surface known. Of these, the Marsden and Kracht groups move in orbits situated in a spatial corridor of the daytime Arietid meteoroid stream. The orbits of comets of the Meyer group are not very different from those of the Marsden and Kracht groups; for the purpose of our study, we …
Do blue galaxy-clusters have hot intracluster gas?
Oguri, Masamune; Kodama, Tadayuki; Okabe, Nobuhiro +5 more
We present herein a systematic X-ray analysis of blue galaxy clusters at z = 0.84 discovered by the Subaru telescope. The sample consisted of 43 clusters identified by combining red-sequence and blue-cloud surveys, covering a wide range of emitter fractions (i.e., 0.3-0.8). The spatial extent of the over-density region of emitter galaxies was appr…
Constraining the Planet Occurrence Rate around Halo Stars of Potentially Extragalactic Origin
Price-Whelan, Adrian M.; Yoshida, Stephanie; Grunblatt, Samuel
The search for planets orbiting other stars has recently expanded to include stars from galaxies outside the Milky Way. With the Transiting Exoplanet Survey Satellite (TESS) and Gaia surveys, photometric and kinematic information can be combined to identify transiting planet candidates of extragalactic origin. Here, 1080 low-luminosity red-giant b…
Kinematics of OB Stars with Data from the LAMOST and Gaia Catalogues
Bobylev, V. V.; Bajkova, A. T.; Karelin, G. M.
We have analyzed the kinematics of OB stars from the list by Xiang et al. (2021) that contains ${∼}13 000$ single OB stars. For these stars there are photometric distance estimates and proper motions from the Gaia catalogue and line-of-sight velocities from the LAMOST catalogue. Based on a sample of single OB stars and using the photometric distan…