33 citations · 175 across the 23 of their papers we have counts for
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Spectral Energy Distribution and Polarimetric Properties of Dust in the Interstellar Comet 3I/ATLAS
Seungwon Choi, Masateru Ishiguro, Hiroyuki Naito +13
The interstellar comet 3I/ATLAS exhibits unusual polarimetric properties compared with Solar System comets, while constraints on its fundamental physical properties, such as dust a…
Dust Properties of the Interstellar Object 3I/ATLAS Revealed by Optical and Near-Infrared Polarimetry
Seungwon Choi, Masateru Ishiguro, Jun Takahashi +17
We present independent polarimetric observations of the interstellar object 3I/ATLAS, including the first near-infrared polarimetric measurements. Using imaging polarimeters, we me…
Pre-perihelion Emergence of the CN Gas Coma in 3I/ATLAS Temporally and Spatially Resolved by the 7-Dimensional Telescope
Gregory S. H. Paek, Myungshin Im, Mankeun Jeong +8
We present time-series medium-band (R~20-40) observations of the third interstellar object 3I/ATLAS (C/2025 N1) obtained with the 7-Dimensional Telescope (7DT), enabling spatially…
Optical and Near-Infrared Contemporaneous Polarimetry of C/2023 A3 (Tsuchinshan-ATLAS)
Bumhoo Lim, Masateru Ishiguro, Jun Takahashi +11
We conducted contemporaneous optical and near-infrared polarimetric and spectroscopic observations of C/2023 A3 (Tsuchinshan-ATLAS, hereafter T-A) from 2024 October 16 to December…
New evidence supporting past dust ejections from active asteroid (4015) Wilson-Harrington
Sunho Jin, Masateru Ishiguro, Jooyeon Geem +15
Context. (4015) Wilson-Harrington (hereafter, WH) was discovered as a comet in 1949 but has a dynamical property consistent with that of a near-Earth asteroid. Although there is a…
Study of hydrated asteroids via their polarimetric properties at low phase angles
Jooyeon Geem, Masateru Ishiguro, Hiroyuki Naito +11
Context. Ch-type asteroids are distinctive among other dark asteroids in that they exhibit deep negative polarization branches (NPBs). Nevertheless, the physical and compositional…
Quantitative grain size estimation on airless bodies from the negative polarization branch. I. Insights from experiments and lunar observations
Yoonsoo P. Bach, Masateru Ishiguro, Jun Takahashi +4
This work explores characteristics of the negative polarization branch (NPB), which occurs in scattered light from rough surfaces, with particular focus on the effects of fine part…
Quantitative grain size estimation on airless bodies from the negative polarization branch. II. Dawn mission targets (4) Vesta and (1) Ceres
Yoonsoo P. Bach, Masateru Ishiguro, Jun Takahashi +4
Context. Sunlight scattered from the surface of an airless body is generally partially polarized, and the corresponding polarization state includes information about the scattering…
Spectral Type and Geometric Albedo of (98943) 2001 CC21, the Hayabusa2# Mission Target
Jooyeon Geem, Masateru Ishiguro, Mikael Granvik +18
We conducted optical polarimetry and near-infrared spectroscopy of JAXA's Hayabusa2# mission target, (98943) 2001 CC21, in early 2023. Our new observations indicated that this aste…
Simultaneous Multicolor Photometry of the DESTINY target asteroid (3200) Phaethon
Jin Beniyama, Tomohiko Sekiguchi, Daisuke Kuroda +11
Accurate estimation of brightness of (3200) Phaethon up to lower phase angles are essential for planning of the on-board camera of the DESTINY mission. We have carried out in…
Spectral evolution of dark asteroid surfaces induced by space weathering over a decade
Sunao Hasegawa, Francesca E. DeMeo, Michael Marsset +20
The surface of airless bodies like asteroids in the Solar System are known to be affected by space weathering. Experiments simulating space weathering are essential for studying th…
(3200) Phaethon Polarimetry in the Negative Branch: New Evidence for the Anhydrous Nature of the DESTINY+ Target Asteroid
Jooyeon Geem, Masateru Ishiguro, Jun Takahashi +23
We report on the first polarimetric study of (3200) Phaethon, the target of JAXA's DESTINY mission, in the negative branch to ensure its anhydrous nature and to derive an accur…
Polarimetric Properties of the Near--Sun Asteroid (155140) 2005 UD in Comparison with Other Asteroids and Meteoritic Samples
Masateru Ishiguro, Yoonsoo P. Bach, Jooyeon Geem +26
The investigation of asteroids near the Sun is important for understanding the final evolutionary stage of primitive solar system objects. A near-Sun asteroid, (155140) 2005 UD, ha…
A polarimetric study of asteroids in comet-like orbits
Jooyeon Geem, Masateru Ishiguro, Yoonsoo P. Bach +16
Context. Asteroids in comet-like orbits (ACOs) consist of asteroids and dormant comets. Due to their similar appearance, it is challenging to distinguish dormant comets from ACOs v…
Thermal radiation pressure as a possible mechanism for losing small particles on asteroids
Yoonsoo P. Bach, Masateru Ishiguro
Context. Recent observations of dust ejections from active asteroids, including (3200) Phaethon, have drawn considerable interest from planetary astronomers studying the generation…
Polarimetric signature of the oceans as detected by near-infrared Earthshine observations
J. Takahashi, Y. Itoh, T. Matsuo +3
Context. The discovery of an extrasolar planet with an ocean has crucial importance in the search for life beyond Earth. The polarimetric detection of specularly reflected light fr…
Implications of High Polarization Degree for the Surface State of Ryugu
Daisuke Kuroda, Jooyeon Geem, Hiroshi Akitaya +19
The asteroid exploration project "Hayabusa2" has successfully returned samples from the asteroid (162173) Ryugu. In this study, we measured the linear polarization degrees of Ryugu…
The Geometric Albedo of (4179) Toutatis Estimated from KMTNet DEEP-South Observations
Yoonsoo P. Bach, Masateru Ishiguro, Sunho Jin +6
We derive the geometric albedo of a near-Earth asteroid, (4179) Toutatis, to investigate its surface physical conditions. The asteroid has been studied rigorously not only via grou…
Thermal Modeling of Comet-Like Objects from AKARI Observation
Yoonsoo P. Bach, Masateru Ishiguro, Fumihiko Usui
We investigated the physical properties of the comet-like objects 107P/(4015) Wilson--Harrington (4015WH) and P/2006 HR30 (Siding Spring; HR30) by applying a simple thermophysical…
Polarimetric Study of Near-Earth Asteroid (1566) Icarus
Masateru Ishiguro, Daisuke Kuroda, Makoto Watanabe +13
We conducted a polarimetric observation of the fast-rotating near-Earth asteroid (1566) Icarus at large phase (Sun-asteroid-observer's) angles = 57 deg--141deg around the 2015 s…