224 citations · 642 across the 21 of their papers we have counts for
21 papers
OGLE-2018-BLG-0584 and KMT-2018-BLG-2119: two microlensing events with two lens masses and two source stars
Cheongho Han, Andrzej Udalski, Youn Kil Jung +34
We conduct a systematic investigation of the microlensing data collected during the previous observation seasons for the purpose of reanalyzing anomalous lensing events with no sug…
A Photometric and Spectroscopic Study of the Short-Period Algol EW Boötis with a Sct Pulsator
Hye-Young Kim, Kyeongsoo Hong, Chun-Hwey Kim +4
In this paper, we present TESS photometry and high-resolution spectra of the short-period Algol EW Boo. We obtained double-lined radial velocities (RVs) from the time-series spectr…
KMT-2018-BLG-1988Lb: microlensing super-Earth orbiting a low-mass disk dwarf
Cheongho Han, Andrew Gould, Michael D. Albrow +20
We reexamine high-magnification microlensing events in the previous data collected by the KMTNet survey with the aim of finding planetary signals that were not noticed before. In t…
OGLE-2019-BLG-0468Lb,c: two microlensing giant planets around a G-type star
Cheongho Han, Andrzej Udalski, Chung-Uk Lee +37
With the aim of interpreting anomalous lensing events with no suggested models, we conducted a project of reinvestigating microlensing data in and before the 2019 season. In this w…
Two contact binaries with mass ratios close to the minimum mass ratio
Kai Li, Qi-Qi Xia, Chun-Hwey Kim +5
The cut-off mass ratio is under debate for contact binaries. In this paper, we present the investigation of two contact binaries with mass ratios close to the low mass ratio limit.…
Photometric study and absolute parameters estimation of six totally eclipsing contact binaries
Kai Li, Qi-Qi Xia, Chun-Hwey Kim +6
High precision CCD observations of six totally eclipsing contact binaries were presented and analyzed. It is found that only one target is an A-type contact binary (V429 Cam), whil…
KMT-2019-BLG-1715: planetary microlensing event with three lens masses and two source stars
Cheongho Han, Andrzej Udalski, Doeone Kim +61
We investigate the gravitational microlensing event KMT-2019-BLG-1715, of which light curve shows two short-term anomalies from a caustic-crossing binary-lensing light curve: one w…
KMT-2018-BLG-1025Lb: microlensing super-Earth planet orbiting a low-mass star
Cheongho Han, Andrzej Udalski, Chung-Uk Lee +32
We aim to find missing microlensing planets hidden in the unanalyzed lensing events of previous survey data. For this purpose, we conduct a systematic inspection of high-magnificat…
Spin Change of Asteroid 2012 TC4 probably by Radiation Torques
Hee-Jae Lee, Josef Ďurech, David Vokrouhlický +9
Asteroid 2012 TC4 is a small (10 m) near-Earth object that was observed during its Earth close approaches in 2012 and 2017. Earlier analyses of light curves revealed its exci…
Physical Nature of the Eclipsing δ Scuti Star AO Serpentis
Jang-Ho Park, Jae Woo Lee, Kyeongsoo Hong +2
We present the absolute properties of the eclipsing binary AO Ser with a pulsating component from our photometric and high-resolution spectroscopic observations, which were pe…
Four Microlensing Planets with Faint-source Stars Identified in the 2016 and 2017 Season Data
Cheongho Han, Andrzej Udalski, Doeon Kim +32
Microlensing planets occurring on faint source stars can escape detection due to their weak signals. Occasionally, detections of such planets are not reported due to the difficulty…
The first light curve modeling and orbital period change investigation of nine contact binaries around the short period cut-off
Kai Li, Chun-Hwey Kim, Qi-Qi Xia +5
In this paper, we present the first light curve synthesis and orbital period change analysis of nine contact binaries around the short period limit. It is found that all these syst…
OGLE-2016-BLG-1227L: A Wide-separation Planet from a Very Short-timescale Microlensing Event
Cheongho Han, Andrzej Udalski, Andrew Gould +30
We present the analysis of the microlensing event OGLE-2016-BLG-1227. The light curve of this short-duration event appears to be a single-lens event affected by severe finite-sourc…
Investigation of surface homogeneity of (3200) Phaethon
Hee-Jae Lee, Myung-Jin Kim, Dong-Heun Kim +7
Time-series multi-band photometry and spectrometry were performed in Nov.-Dec. 2017 to investigate the homogeneity of the surface of asteroid (3200) Phaethon. We found that Phaetho…
MOA-2016-BLG-319Lb: Microlensing Planet Subject to Rare Minor-Image Perturbation Degeneracy in Determining Planet Parameter
Cheongho Han, Ian A. Bond, Andrew Gould +42
We present the analysis of the planetary microlensing event MOA-2016-BLG-319. The event light curve is characterized by a brief ( days) anomaly near the peak produced by mi…
KMT-2016-BLG-2052L: Microlensing Binary Composed of M Dwarfs Revealed from a Very Long Time-scale Event
Cheongho Han, Youn Kil Jung, Yossi Shvartzvald +26
We present the analysis of a binary microlensing event KMT-2016-BLG-2052, for which the lensing-induced brightening of the source star lasted for 2 seasons. We determine the lens m…
Absolute dimensions and evolutionary status of the semi-detached Algol W Ursae Minoris
Jang-Ho Park, Kyeongsoo Hong, Jae-Rim Koo +2
Double-lined eclipsing binaries allow accurate and direct determination of fundamental parameters such as mass and radius for each component, and they provide important constraints…
Instabilities in Interacting Binary Stars
Ivan L. Andronov, K. D. Andrych, K. A. Antoniuk +43
The types of instability in the interacting binary stars are reviewed. The project "Inter-Longitude Astronomy" is a series of smaller projects on concrete stars or groups of stars.…
Photometric defocus observations of transiting extrasolar planets
Tobias C. Hinse, Wonyong Han, Jo-Na Yoon +3
We have carried out photometric follow-up observations of bright transiting extrasolar planets using the CbNUOJ 0.6m telescope. We have tested the possibility of obtaining high pho…
The First Comprehensive Photometric Study of the Algol-type System CL Aurigae
Jae Woo Lee, Chun-Hwey Kim, Duck Hyun Kim +3
We present the first extensive photometric results of CL Aur from our BVRI CCD photometry made on 22 nights from 2003 November through 2005 February. Fifteen new timings of minimum…
The sdB+M Eclipsing System HW Virginis and its Circumbinary Planets
Jae Woo Lee, Seung-Lee Kim, Chun-Hwey Kim +4
For the very short-period sdB eclipsing binary HW Vir, we present new CCD photometry made from 2000 through 2008. In order to obtain consistency of the binary parameters, our new l…