Search Publications
Infrared Properties of OGLE4 Mira Variables in Our Galaxy
Suh, Kyung-Won
We investigate infrared properties of OGLE4 Mira variables in our Galaxy. For each object, we cross-identify the AllWISE, 2MASS, Gaia, and IRAS counterparts. We present various IR two-color diagrams (2CDs) and period-magnitude and period-color relations for the Mira variables. Generally, the Mira variables with longer periods are brighter in the I…
Relation between Black Hole Mass and Bulge Luminosity in Hard X-Ray Selected Type 1 AGNs
Ho, Luis C.; Barth, Aaron J.; Kim, Minjin +1 more
Using I-band images of 35 nearby (z < 0.1) type 1 active galactic nuclei (AGNs) obtained with Hubble Space Telescope, selected from the 70-month Swift-BAT X-ray source catalog, we investigate the photometric properties of the host galaxies. With a careful treatment of the point-spread function (PSF) model and imaging decomposition, we robustly …
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 …
Stellar Magnetic Activity Measure Based on IUE Mg II h+k Emission Lines of Main-Sequence G Stars
Choi, Hwajin; Yi, Yu; Kim, Dowoon
Stellar magnetic activity is important for formulating the evolution of the star. To represent the stellar magnetic activity, the S index is defined using the Ca II H+K flux measure from the Mount Wilson Observatory. Mg II lines are generated in a manner similar to the formation of Ca II lines, which are more sensitive to weak chromospheric activi…
Kinematic Classification of Coronal Mass Ejections in LASCO C3 Field of View
Moon, Yong-Jae; Lee, Harim; Cho, Il-Hyun +2 more
In this study, we perform a statistical investigation of the kinematic classification of 4264 coronal mass ejections (CMEs) from 1996 to 2015 observed by SOHO/LASCO C3. Using the constant acceleration model, we classify these CMEs into three groups: deceleration, constant velocity, and acceleration motion. For this, we devise three different class…
Comparison of LOS Doppler Velocities and Non-Thermal Line Widths in the Off-Limb Solar Corona Measured Simultaneously by CoMP and Ninode/EIS
Lee, Kyoung-Sun; Cho, Kyung-Suk; Lee, Jae-Ok +1 more
Observations of line of sight (LOS) Doppler velocity and non-thermal line width in the off-limb solar corona are often used for investigating the Alfvén wave signatures in the corona. In this study, we compare LOS Doppler velocities and non-thermal line widths obtained simultaneously from two different instruments, Coronal Multichannel Polarimeter…
Poorly Studied Eclipsing Binaries in the Field of DO Draconis: V454 Dra and V455 Dra
Kim, Yonggi; Yoon, Joh-Na; Andronov, Ivan L. +3 more
We report an analysis of two poorly studied eclipsing binary stars, GSC 04396-00605 and GSC 04395-00485 (recently named V455 Dra and V454 Dra, respectively). Photometric data of the two stars were obtained using the 1-m Korean telescope of the LOAO operated by KASI while monitoring the cataclysmic variable DO Dra in the frame of the Inter-Longitud…
207 New Open Star Clusters within 1 kpc from Gaia Data Release 2
Sim, Gyuheon; Lee, Sang Hyun; Ann, Hong Bae +1 more
We conducted a survey of open clusters within 1 kpc from the Sun using the astrometric and photometric data of the Gaia Data Release 2. We found 655 cluster candidates by visual inspection of the stellar distributions in proper motion space and spatial distributions in l-b space. All of the 655 cluster candidates have a well defined main-sequence …
Investigating the Pulsar Wind Nebula 3C 58 Using Emission Models
An, Hongjun; Park, Jaegeun; Kim, Seungjong
We present IR flux density measurements, models of the broadband SED, and results of SED modeling for the Pulsar Wind Nebula (PWN) 3C 58. We find that the Herschel flux density seems to be slightly lower than suggested by interpolation of previous measurements in nearby wavebands, implying that there may be multiple electron populations in 3C 58. …
Origin and Status of Low-Mass Candidate Hypervelocity Stars
Koo, Jae-Rim; Beers, Timothy C.; Lee, Young Sun +2 more
We present an analysis of the chemical abundances and kinematics of six low-mass dwarf stars, previously claimed to be candidate hypervelocity stars (HVSs). We obtained moderate-resolution (R=6000) spectra of these stars to estimate the abundances of several chemical elements (Mg, Si, Ca, Ti, Cr, Fe, and Ni), and derived their space velocities and…