A5007609691- Astro and Planetary Science
- Planetary Science and Exploration
- Isotope Analysis in Ecology
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Atmospheric Ozone and Climate
- Spacecraft and Cryogenic Technologies
- Space Exploration and Technology
- Geological and Geochemical Analysis
- Gamma-ray bursts and supernovae
- Geology and Paleoclimatology Research
- Nuclear Physics and Applications
- Ionosphere and magnetosphere dynamics
- Geophysics and Gravity Measurements
- Astronomical and nuclear sciences
- Chemical Thermodynamics and Molecular Structure
- solar cell performance optimization
- Hydrocarbon exploration and reservoir analysis
- Space Satellite Systems and Control
- Scientific Research and Discoveries
- Mass Spectrometry Techniques and Applications
- Meteorological Phenomena and Simulations
- Adaptive optics and wavefront sensing
Infrared Processing and Analysis Center
2023-2024
California Institute of Technology
2023-2024
Technische Universität Braunschweig
2021-2023
Seoul National University
2016-2019
Astronomy and Space
2019
The near-Earth asteroid (3200) Phaethon is the parent body of Geminid meteor stream. also an active with a very blue spectrum. We conducted polarimetric observations this over wide range solar phase angles α during its close approach to Earth in autumn 2016. Our observation revealed that exhibits extremely large linear polarization: P = 50.0 ± 1.1% at 106.5°, and maximum even larger. strong polarization implies Phaethon's geometric albedo lower than current estimate obtained through...
ABSTRACT Comet 67P/Churyumov–Gerasimenko (67P) become observable for the first time in 2021 since Rosetta rendezvous 2014–2016. Here, we present pre-perihelion polarimetric measurements of 67P from performed with Very Large Telescope (VLT), as well post-perihelion 2015 to 2016 obtained VLT and William Herschel Telescope. This new data covers a phase angle range ∼4○−50○ presents unprecedentedly high S/N ratio. Complementing previous measurements, curve resembles that other Jupiter family...
We report a new imaging spectroscopic observation of Oort-cloud comet C/2017 K2 (hereafter K2) on its way to perihelion at 2.53 au, around heliocentric distance where H2O ice begins play key role in activation. Normalized reflectances over 6 500--8 500 AA for inner and outer comae are 9.7+/-0.5 7.2+/-0.3 % (10^3 AA)^-1, respectively, the latter being consistent with slope observed when was beyond orbit Saturn. The dust coma time appears contain three distinct populations: mm-sized chunks...
This study presents the first optical (420–930 nm) spectropolarimetric of a sample large (≳100 km in diameter) C-complex asteroids observing circumstances for which light scattered by asteroid surfaces undergoes so-called negative polarization. We analyzed total 64 different subclasses, using archival polarimetric and reflectance data to refine link between parameters surface properties asteroids. find consistent difference polarization spectra containing phyllosilicates those without, is...
We present an optical and near-infrared (hereafter NIR) polarimetric study of a comet C/2013 US10 (Catalina) observed on UT 2015 December 17–18 at phase angles α = 521–531. Additionally, we obtained spectrum multi-band images to examine the influence gas emission. find that signals are significantly influenced by emission; is, gas-to-total intensity ratio varies from 5 30% in RC 3%–18% IC bands, depending position coma. derive "gas-free dust polarization degrees" 13.8% ± 1.0% 12.5% 1.1%...
The investigation of asteroids near the Sun is important for understanding final evolutionary stage primitive solar system objects. A near-Sun asteroid, (155140) 2005 UD, has orbital elements similar to those (3200) Phaethon (the target asteroid JAXA's $DESTINY^+$ mission). We conducted photometric and polarimetric observations UD found that this exhibits a polarization phase curve over wide range observed angles ($ \alpha = 20 - 105^\circ $) but different from (101955) Bennu (162173) Ryugu...
Multiple outbursts of a Jupiter-family comet, 15P/Finlay, occurred from late 2014 to early 2015. We conducted an observation the comet after first outburst and subsequently witnessed another on 2015 January 15.6-15.7. The gas, consisting mostly C2 CN, dust particles expanded at speeds 1,110 +/- 180 m/s 570 40 heliocentric distance 1.0 AU. estimated maximum ratio solar radiation pressure with respect gravity beta_max = 1.6 0.2, which is consistent porous composed silicates organics. found...
We report our new spectropolarimetric observations for 67P dust over 4,000--9,000 Angstrom using the ESO/Very Large Telescope in January--March 2016 (phase angle ranging $\sim$26--5 deg) to constrain properties of particles and therefrom diagnose environment its coma near-surface layer at around end Southern summer comet. examined optical behaviours dust, which, together with Rosetta colour data, were used search evolution cometocentric distance. Modelling was also conducted identify...
Abstract Asteroids with low orbital perihelion distances experience extreme heating from the Sun that can modify their surfaces and trigger nontypical activity mechanisms. These objects are generally difficult to observe ground-based telescopes due frequent proximity Sun. The Near-Earth Object (NEO) Surveyor mission, however, will regularly survey down solar elongations of 45° is well suited for detection characterization low-perihelion asteroids. Here, we use simulation software tools...
Abstract Comets, relics from the early solar system, consist of dust and ice. The ice sublimates as comets approach Sun, ejecting their nuclei seen activity. Different volatiles sublimate at different Sun–comet distances eject unique sizes, structures, compositions. In this study, we present new polarimetric observations Oort cloud comet C/2017 K2 (Pan-STARRS) in R- I -filter domains before, during, after its crossover water-ice sublimation regime phase angles 15.°9, 10.°5, 20.°0,...
Comets, relics from the early solar system, consist of dust and ice. The ice sublimates as comets approach Sun, ejecting their nuclei seen activity. Different volatiles sublimate at different Sun-comet distances eject unique sizes, structures, compositions. In this study, we present new polarimetric observations Oort-cloud comet C/2017 K2 (PANSTARRS) in R I-filter domains before, during, after its crossover water-ice sublimation regime phase angles 15.9\arcdeg, 10.5\arcdeg, 20.0\arcdeg,...
We report our new analysis of Oort-cloud comet C/2020 T2 (Palomar) (T2) observed at 2.06 au from the Sun (phase angle 28.5 deg) about two weeks before perihelion. lacks a significant dust tail in scattered light, showing strong central condensation coma throughout apparition, reminiscent so-called Manx comets. Its spectral slope polarized light increases and decreases J (1.25 um) H (1.65 bands, respectively, resulting an overall negative (blue) (-0.31+/-0.14 % um^-1) contrast to red...
This paper reports a new optical observation of 17P/Holmes one orbital period after the historical outburst event in 2007. We detected not only common dust tail near nucleus, but also long narrow structure that extended along position angle 274.6+/- 0.1 degree beyond field view Kiso Wide Field Camera, i.e., >0.2 eastward and >2.0 westward from nuclear position. The width decreased with increasing distance nucleus. obtained total cross section view, C= (2.3 +/- 0.5)x10^10 m^2. From angle,...
We performed a monitoring observation of Jupiter-Family comet, 17P/Holmes, during its 2014 perihelion passage to investigate secular change in activity. The comet has drawn the attention astronomers since historic outburst 2007, and this occasion was first then. analyzed obtained data using aperture photometry package derived Afrho parameter, proxy for dust production rate. found that showed asymmetric properties with respect passage: it increased moderately from 100 cm at heliocentric...
Context. The thermal and radiative environments encountered by asteroids have shaped their surface features. Recent observations focused on in the main belt showed indications for ices organics interiors of that were likely significant prebiotic Earth. They stand out reflectance spectra as darker, redder colours than most colocated asteroids. Aims. We probe environment large (>80km diameter) T-type This taxonomic type is relatively ill-constrained an independent group. discuss place...
Context. Asteroids in comet-like orbits (ACOs) consist of asteroids and dormant comets. Due to their similar appearance, it is challenging distinguish comets from ACOs via general telescopic observations. Surveys for discriminating the ACO population have been conducted spectroscopy or optical mid-infrared photometry. However, they not through polarimetry. Aims. We first polarimetric research ACOs. Methods. a linear pilot survey three ACOs: (944) Hidalgo, (3552) Don Quixote, (331471) 1984...
Spectropolarimetry is a powerful technique for investigating the physical properties of gas and solid materials in cometary comae without mutual contamination, but there have been few spectropolarimetric studies to extract each component. We attempt derive continuum polarization degree comet 2P/Encke, free from influence molecular emissions. The target unique that it has an orbit dynamically decoupled Jupiter like main-belt asteroids, while ejecting dust ordinary comets. observed using...
We present a possible correlation between the properties of scattered and thermal radiation from dust principal characteristics responsible for this relationship. To end, we use NASA/PDS archival polarimetric data on cometary in Red (0.62--0.73 $μ$m) K (2.00--2.39 domains to leverage relative excess polarisation degree comet average trend at given phase angle ($P_{\rm excess}$) as metric dust's light characteristics. The flux silicate emissions continuum around 10 $μ$m ($F_{\rm Si}/F_{\rm...
Aims. We aim to constrain the size and porosity of ejected dust particles from comet 252P/LINEAR their evolution near perihelion via near-infrared multiband polarimetry. A close approach Earth in March 2016 (~0.036 au) provided a rare opportunity for sampling with high spatial resolution. Methods. made NIR JHKS bands polarimetric observations 12 days perihelion, interspersed between broadband optical imaging over four months. In addition, dynamical simulation was performed 1000 yr backward...
Asteroids with low orbital perihelion distances experience extreme heating from the Sun that can modify their surfaces and trigger non-typical activity mechanisms. These objects are generally difficult to observe ground-based telescopes due frequent proximity Sun. The Near Earth Object Surveyor mission, however, will regularly survey down Solar elongations of 45 degrees is well-suited for detection characterization low-perihelion asteroids. Here, we use simulation software tools developed...
Abstract Near-Earth Object (NEO) Surveyor will detect asteroids and comets using mid-infrared thermal emission, however ground-based followup resources require knowledge of the expected visible light brightness in order to plan characterization observations. Here we describe range visual-to-infrared colors that NEOs detected by span, demonstrate for objects have no previously reported Visual band observations, estimates Johnson Visual-band based on infrared flux alone significant...
Comet 67P/Churyumov-Gerasimenko (67P) become observable for the first time in 2021 since Rosetta rendezvous 2014--16. Here, we present pre-perihelion polarimetric measurements of 67P from performed with Very Large Telescope (VLT), as well post-perihelion 2015--16 obtained VLT and William Herschel (WHT). This new data covers a phase angle range ~4-50{\deg} presents unprecedentedly high S/N ratio. Complementing previous measurements, curve resembles that other Jupiter family comets...
As one of the most thermally stable solvents, water is critical to grasping material evolution planetary systems. Ch-type asteroids show clear signs on their surfaces, anticipated serve as a local reservoir in today’s main asteroid belt region and also parent bodies CM meteorites that are presumably primary source early Earth. Aside from composition building blocks, little known about physical makeup dust particles, which related environmental information before they settled...