34 citations · 115 across the 20 of their papers we have counts for
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Experimental evidence for physical alteration of fine regolith on near-Sun asteroids
Jooyeon Geem, Mikael Granvik, Georgios Tsirvoulis +5
The surfaces of airless bodies evolve through processes such as (micro)meteoroid impacts and thermal fatigue, which modify physical properties such as grain size, porosity, and min…
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…
Tianwen-2 target asteroid (469219) Kamo'oalewa probably develops an Itokawa-compositional but ultra-highly space-weathered surface
Pengfei Zhang, Guozheng Zhang, Zichen Wei +45
China's Tianwen-2 mission plans to return samples from a small, rapidly spinning Earth quasi-satellite (469219) Kamo'oalewa. Previous studies linked Kamo'oalewa to lunar compositio…
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…
Instantaneous thermally-driven erosion can explain dearth of dark near-Sun asteroids
Georgios Tsirvoulis, Mikael Granvik, Leonard Schirner +3
Recent models of the near-Earth asteroid population show that asteroids must be super-catastrophically destroyed when they evolve to orbits with perihelion passages well inside of…
SPHEREx Pre-Perihelion Mapping of , , and in Interstellar Object 3I/ATLAS
Carey M. Lisse, Yoonsoo P. Bach, Brendan P. Crill +35
From 01- to 15-Aug-2025UT, the SPHEREx spacecraft observed interstellar object 3I/ATLAS. Using spectrophotometry at m, light curves, spectra, and imaging of…
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…
Discovery of two TNO-like bodies in the asteroid belt
Sunao Hasegawa, Michael Marsset, Francesca E. DeMeo +6
Two extremely red main-belt asteroids: 203 Pompeja and 269 Justitia, were identified from combined visible and near-infrared spectroscopic observations collected at the IRTF and SA…
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…