Search Publications
KMT-2017-BLG-0673Lb and KMT-2019-BLG-0414Lb: Two microlensing planets detected in peripheral fields of KMTNet survey
Han, Cheongho; Lee, Chung-Uk; Zang, Weicheng +18 more
Aims: We investigate the microlensing data collected during the 2017-2019 seasons in the peripheral Galactic bulge fields with the aim of finding planetary signals in microlensing light curves observed with relatively sparse coverage.
Methods: We first sort out lensing events with weak short-term anomalies in the lensing light curves fro…
Probing the surface environment of large T-type asteroids
Hasegawa, Sunao; Agarwal, Jessica; Fornasier, Sonia +2 more
Context. The thermal and radiative environments encountered by asteroids have shaped their surface features. Recent observations have focused on asteroids in the main belt and showed indications for ices and organics in the interiors of the asteroids that were likely significant on prebiotic Earth. They stand out in reflectance spectra as darker, …
Migrating Dynamo Waves and Consequences for Stellar Current Sheets
Sokoloff, Dmitry; Malova, Helmi; Popov, Victor +2 more
We study the relation between stellar dynamo-wave propagation and the structure of the stellar magnetic field. Modeling dynamo waves by the well-known Parker migratory dynamo, we vary the intensity of dynamo drivers in order to obtain activity-wave propagation toward the Equator (as in the solar-activity cycle) or towards the Poles. We match the m…
Additions to the Spectrum of Fe IX in the 110-200 Å Region
Young, Peter R.; Ryabtsev, Alexander N.; Kononov, Edward Y.
The spectrum of eight-times ionized iron, Fe IX, was studied in the 110-200 Å region. A low inductance vacuum spark and a 3 m grazing incidence spectrograph were used for the excitation and recording of the spectrum. Previous analyses of Fe IX have been greatly extended and partly revised. The number of known lines in the 3p 53d-3p
Very Metal-poor Stars in the Solar Vicinity: Age Determination
Villanova, Sandro; Carraro, Giovanni; Plotnikova, Anastasiia +1 more
The ages of the oldest and most metal-poor stars in the Milky Way bear important information on the age of the universe and its standard model. We analyze a sample of 28 extremely metal-poor field stars in the solar vicinity culled from the literature and carefully determine their ages. To this aim, we critically make use of Gaia data to derive th…
X-ray emission of contact binary variables within 1 kpc
Esamdin, Ali; Gu, Wei-Min; Liu, Junhui +3 more
Aims: The X-ray emission of contact binaries (EW-type) is an important facet of such systems. Thus, X-ray emitting EW-type binaries (EWXs) are ideal laboratories for studying the X-ray radiation saturation mechanisms as well as binary evolution. By assembling the largest sample to date of EWXs with periods of less than 1 day from the All-Sky …
A Two-Spacecraft Study of Mars' Induced Magnetosphere's Response to Upstream Conditions
Edberg, Niklas J. T.; Dimmock, Andrew P.; Sánchez-Cano, Beatriz +5 more
This is a two-spacecraft study, in which we investigate the effects of the upstream solar wind conditions on the Martian induced magnetosphere and upper ionosphere. We use Mars Express (MEX) magnetic field magnitude data together with interplanetary magnetic field (IMF), solar wind density, and velocity measurements from the Mars Atmosphere and Vo…
XMM-Newton and TESS observations of the highly variable polar V496 UMa
Schwope, Axel; Ok, Samet
Aims: We studied the temporal and spectral behavior of V496 UMa from the optical to the X-ray regimes.
Methods: We used archival XMM-Newton and TESS observations obtained in 2017 and 2019, respectively, to perform a spectral and timing analysis of the highly variable magnetic CV.
Results: The light curves of the TESS and XMM-Newton …
Bayesian approach for modeling global magnetic parameters for the solar active region
Mandrini, C. H.; Démoulin, P.; Grings, F. +2 more
Context. Active regions (ARs) appear in the solar atmosphere as a consequence of the emergence of magnetic flux tubes. The presence of elongated magnetic polarities in line-of-sight (LOS) magnetograms indicates the existence of twist in the flux tubes that form them. These polarity elongations, referred to as magnetic tongues, bias the measurement…
Planetary nebulae with Wolf-Rayet-type central stars - IV. NGC 1501 and its mixing layer
Guerrero, M. A.; Toalá, J. A.; Todt, H. +4 more
Theory predicts that the temperature of the X-ray-emitting gas (~106 K) detected from planetary nebulae (PNe) is a consequence of mixing or thermal conduction when in contact with the ionized outer rim (~104 K). Gas at intermediate temperatures (~105 K) can be used to study the physics of the production of X-ray-em…