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15 results on '"Daehyeon Oh"'

1. Energetic particle flux measurements from the Korean space weather monitor particle detector: a comparative study with the MPS-HI onboard GOES-16

Author

Daehyeon Oh, Jiyoung Kim, Paul T. M. Loto’aniu, Han-Cheol Lim, Dae-Young Lee, and Dohyeong Kim

Subjects
Space weather, In situ measurement, Energetic particle, High-energy electron, High-energy proton, Geostationary orbit, Geography. Anthropology. Recreation, Geodesy, QB275-343, Geology, QE1-996.5
Abstract

Abstract The Korean space weather monitor (KSEM) aboard the GEO-KOMPSAT-2A (GK2A) has been continuously measuring energetic particle flux in geostationary orbit at 128.2°E longitude since July 2019. The particle detector (PD) component of KSEM comprises six particle telescopes viewing different directions that provide near-real-time electron flux observations within the energy range of 100 keV to 3.8 MeV. The KSEM PD on the GK2A satellite, together with the MPS-HI on the GOES-16 satellite 156.6° away, can provide valuable simultaneous observations of the asymmetric space environment and contributes to our understanding of this dynamic region. In this study, we present recent energetic electron flux measurements obtained from the KSEM PD and conduct preliminary cross-comparisons with data from the Magnetosphere Particle Sensor–High (MPS-HI) PD, which is part of the SEISS instrument suite onboard GOES-16. The inter-comparisons show that the electron fluxes of the two detectors are in reasonable similarity except for some energy bands under quiet conditions. Additionally, we provide a brief overview of the electron flux responses of both KSEM PD and MPS-HI under enhanced space environment conditions, which shows differences based on sensor characteristics and satellite location. Graphical Abstract

Published
2024
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2. Satellite-based In-situ Monitoring of Space Weather

Author

Daehyeon Oh, Jiyoung Kim, Hyesook Lee, and Kun-Il Jang

Subjects
space weather, geostationary orbit, artificial satellite, Astronomy, QB1-991
Abstract

Many recent satellites have mission periods longer than 10 years; thus, satellite-based local space weather monitoring is becoming more important than ever. This article describes the instruments and data applications of the Korea Space wEather Monitor (KSEM), which is a space weather payload of the GeoKompsat-2A (GK-2A) geostationary satellite. The KSEM payload consists of energetic particle detectors, magnetometers, and a satellite charging monitor. KSEM will provide accurate measurements of the energetic particle flux and three-axis magnetic field, which are the most essential elements of space weather events, and use sensors and external data such as GOES and DSCOVR to provide five essential space weather products. The longitude of GK-2A is 128.2° E, while those of the GOES satellite series are 75° W and 135° W. Multi-satellite measurements of a wide distribution of geostationary equatorial orbits by KSEM/GK-2A and other satellites will enable the development, improvement, and verification of new space weather forecasting models. KSEM employs a service-oriented magnetometer designed by ESA to reduce magnetic noise from the satellite in real time with a very short boom (1 m), which demonstrates that a satellite-based magnetometer can be made simpler and more convenient without losing any performance.

Published
2018
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3. Subaru Near-Infrared Imaging Polarimetry of Misaligned Disks Around the SR 24 Hierachical Triple System

Author

Satoshi Mayama, Sebastian Perez, Nobuhiko Kusakabe, Takayuki Muto, Takashi Tsukagoshi, Michael L. Sitko, Michihiro Takami, Jun Hashimoto, Ruobing Dong, Jungmi Kwon, Saeko S. Hayashi, Tomoyuki Kudo, Masayuki Kuzuhara, Katherine Follette, Misato Fukagawa, Munetake Momose, Daehyeon Oh, Jerome de Leon, Eiji Akiyama, John P. Wisniewski, Yi Yang, Lyu Abe, Wolfgang Brandner, Timothy D. Brandt, Michael Bonnefoy, Joseph C. Carson, Jeffrey Chilcote, Thayne Currie, Markus Feldt, Miwa Goto, Carol A Grady, Tyler Groff, Olivier Guyon, Yutaka Hayano, Masahiko Hayashi, Thomas Henning, Klaus W. Hodapp, Miki Ishii, Masanori Iye, Markus Janson, Nemanja Jovanovic, Ryo Kandori, Jeremy Kasdin, Gillian R. Knapp, Julien Lozi, Frantz Martinache, Taro Matsuo, Michael W Mcelwain, Shoken Miyama, Jun-Ichi Morino, Amaya Moro-Martin, Takao Nakagawa, Tetsuo Nishimura, Tae-Soo Pyo, Evan A. Rich, Eugene Serabyn, Hiroshi Suto, Ryuji Suzuki, Naruhisa Takato, Hiroshi Terada, Christian Thalmann, Daigo Tomono, Edwin L. Turner, Makoto Watanabe, Toru Yamada, Hideki Takami, Tomonori Usuda, Taichi Uyama, and Motohide Tamura

Subjects
Astronomy
Abstract

The SR 24 multistar system hosts both circumprimary and circumsecondary disks, which are strongly misaligned with each other. The circumsecondary disk is circumbinary in nature. Interestingly, both disks are interacting, and they possibly rotate in opposite directions. To investigate the nature of this unique twin disk system, we present 0.″1 resolution near-infrared polarized intensity images of the circumstellar structures around SR 24, obtained with HiCIAO mounted on the Subaru 8.2 m telescope. Both the circumprimary disk and the circumsecondary disk are resolved and have elongated features. While the position angle of the major axis and radius of the near-IR (NIR) polarization disk around SR 24S are 55° and 137 au, respectively, those around SR 24N are 110° and 34 au, respectively. With regard to overall morphology, the circumprimary disk around SR 24S shows strong asymmetry, whereas the circumsecondary disk around SR 24N shows relatively strong symmetry. Our NIR observations confirm the previous claim that the circumprimary and circumsecondary disks are misaligned from each other. Both the circumprimary and circumsecondary disks show similar structures in 12CO observations in terms of its size and elongation direction. This consistency is because both NIR and 12CO are tracing surface layers of the flared disks. As the radius of the polarization disk around SR 24N is roughly consistent with the size of the outer Roche lobe, it is natural to interpret the polarization disk around SR 24N as a circumbinary disk surrounding the SR 24Nb─Nc system.

Published
2019
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4. SUBARU Near-Infrared Imaging Polarimetry of Misaligned Disks Around The SR24 Hierarchical Triple System

Author

Katherine B. Follette, Gillian R. Knapp, Hideki Takami, Markus Janson, Amaya Moro-Martin, Yutaka Hayano, Sebastián Pérez, Eiji Akiyama, Shoken Miyama, Naruhisa Takato, Michael W. McElwain, Wolfgang Brandner, Takao Nakagawa, Thomas Henning, Masayuki Kuzuhara, Jerome de Leon, Edwin L. Turner, Satoshi Mayama, Tetsuo Nishimura, Takashi Tsukagoshi, Nemanja Jovanovic, Tomonori Usuda, Jeremy Kasdin, Miki Ishii, Thayne Currie, Tyler D. Groff, Nobuhiko Kusakabe, Hiroshi Terada, Evan A. Rich, Misato Fukagawa, Ryo Kandori, Daehyeon Oh, Michihiro Takami, Taichi Uyama, Takayuki Muto, Jun-Ichi Morino, John P. Wisniewski, Frantz Martinache, Taro Matsuo, Munetake Momose, Christian Thalmann, Carol A. Grady, Tomoyuki Kudo, Julien Lozi, Jun Hashimoto, Saeko S. Hayashi, Makoto Watanabe, Eugene Serabyn, Motohide Tamura, Markus Feldt, Miwa Goto, Masanori Iye, Masahiko Hayashi, Joseph C. Carson, Daigo Tomono, Hiroshi Suto, M. Bonnefoy, Tae-Soo Pyo, Olivier Guyon, Timothy D. Brandt, Toru Yamada, Ruobing Dong, Michael L. Sitko, Lyu Abe, Jeffrey Chilcote, Yi Yang, Klaus W. Hodapp, Ryuji Suzuki, Jungmi Kwon, Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France, Ibaraki University, Space Science Institute, Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), Academia Sinica, ISAS/JAXA, National Astronomical Observatory of Japan (NAOJ), Amherst College, and Hokkaido University [Sapporo, Japan]

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010308 nuclear & particles physics, Triple system, business.industry, Polarimetry, FOS: Physical sciences, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Optics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Near infrared imaging, business, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract

The SR24 multi-star system hosts both circumprimary and circumsecondary disks, which are strongly misaligned from each other. The circumsecondary disk is circumbinary in nature. Interestingly, both disks are interacting, and they possibly rotate in opposite directions. To investigate the nature of this unique twin disk system, we present 0.''1 resolution near-infrared polarized intensity images of the circumstellar structures around SR24, obtained with HiCIAO mounted on the Subaru 8.2 m telescope. Both the circumprimary disk and the circumsecondary disk are resolved and have elongated features. While the position angle of the major axis and radius of the NIR polarization disk around SR24S are 55$^{\circ}$ and 137 au, respectively, those around SR24N are 110$^{\circ}$ and 34 au, respectively. With regard to overall morphology, the circumprimary disk around SR24S shows strong asymmetry, whereas the circumsecondary disk around SR24N shows relatively strong symmetry. Our NIR observations confirm the previous claim that the circumprimary and circumsecondary disks are misaligned from each other. Both the circumprimary and circumsecondary disks show similar structures in $^{12}$CO observations in terms of its size and elongation direction. This consistency is because both NIR and $^{12}$CO are tracing surface layers of the flared disks. As the radius of the polarization disk around SR24N is roughly consistent with the size of the outer Roche lobe, it is natural to interpret the polarization disk around SR24N as a circumbinary disk surrounding the SR24Nb-Nc system., Comment: 14 pages, 5 figures, accepted for publication in AJ

Published
2019
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5. The infrared Doppler (IRD) instrument for the Subaru telescope: instrument description and commissioning results

Author

Eiji Kambe, Masato Ishizuka, Hidenori Genda, Yuka Fujii, Masahiro Ogihara, Masahiko Hayashi, Yutaka Hayano, Jungmi Kwon, Masayuki Kuzuhara, Yosuke Tanaka, Tetsuya Nagata, Yasunori Hori, Eiichiro Kokubo, Tomoyuki Kudo, Haruka Baba, Ken Kashiwagi, Tadashi Nakajima, Klaus W. Hodapp, Ko Hosokawa, Donald N. B. Hall, Norio Narita, Naruhisa Takato, Nobuhiko Kusakabe, Yuji Ikeda, Wako Aoki, Takashi Kurokawa, Masahiro N. Machida, Hiroshi Terada, Jun Nishikawa, Takayuki Kotani, Jun-Ichi Morino, Hajime Kawahara, Hiroki Harakawa, Jun Hashimoto, Guyon Olivier, Akihiko Fukui, Bun'ei Sato, Hideyuki Izumiura, Hiroyuki Tako Ishikawa, Daehyeon Oh, Akitoshi Ueda, Hiroshi Suto, Motohide Tamura, Hideki Takami, Tsukasa Kokubo, Masashi Omiya, Taro Matsuo, Shogo Nishiyama, S. Jacobson, Tomonori Usuda, Masahiro Ikoma, Takahiro Mori, Mihoko Konishi, Teruyuki Hirano, Masahide Hidai, Tomoyasu Yamamuro, Nemanja Jovanovic, Evans, Christopher J., Simard, Luc, and Takami, Hideki

Subjects
Physics, 010504 meteorology & atmospheric sciences, Spectrometer, business.industry, Near-infrared spectroscopy, Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, First light, 01 natural sciences, Exoplanet, Radial velocity, symbols.namesake, Optics, 0103 physical sciences, symbols, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Spectral resolution, Subaru Telescope, business, 010303 astronomy & astrophysics, Doppler effect, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract

The Infrared Doppler (IRD) instrument is a fiber-fed high-resolution NIR spectrometer for the Subaru telescope covering the Y,J,H-bands simultaneously with a maximum spectral resolution of 70,000. The main purpose of IRD is a search for Earth-mass planets around nearby M-dwarfs by precise radial velocity measurements, as well as a spectroscopic characterization of exoplanet atmospheres. We report the current status of the instrument, which is undergoing commissioning at the Subaru Telescope, and the first light observation successfully done in August 2017. The general description of the instrument will be given including spectrometer optics, fiber injection system, cryogenic system, scrambler, and laser frequency comb. A large strategic survey mainly focused on late-type M-dwarfs is planned to start from 2019.

Published
2018

6. High-contrast Polarimetry Observation of T Tau Circumstellar Environment

Author

Eugene Serabyn, Wolfgang Brandner, Edwin L. Turner, Toru Yamada, Gillian R. Knapp, Thomas Henning, Satoshi Mayama, Shoken Miyama, Hideki Takami, Yi Yang, Jungmi Kwon, Eiji Akiyama, Michihiro Takami, Hiroshi Terada, Miwa Goto, Ryuji Suzuki, Takuya Suenaga, Naruhisa Takato, Lyu Abe, Yutaka Hayano, Tomoyuki Kudo, Michael W. McElwain, T. Currie, Tomonori Usuda, Ryo Kandori, Markus Janson, Takao Nakagawa, Nobuhiko Kusakabe, Klaus W. Hodapp, Yasuhiro H. Takahashi, Jun-Ichi Morino, Jun Hashimoto, Masayuki Kuzuhara, Tetsuo Nishimura, Roman R. Rafikov, Makoto Watanabe, Masanori Iye, Daehyeon Oh, Joseph C. Carson, Hiroshi Suto, Taro Matsuo, Munetake Momose, Timothy D. Brandt, Motohide Tamura, Tae-Soo Pyo, Christian Thalmann, Olivier Guyon, Amaya Moro-Martin, Miki Ishii, Carol A. Grady, Masahiko Hayashi, Sebastian Egner, Saeko S. Hayashi, Markus Feldt, John P. Wisniewski, Yang, Y [0000-0002-9024-4150], Mayama, S [0000-0002-3424-6266], Akiyama, E [0000-0002-5082-8880], Currie, T [0000-0002-7405-3119], Janson, M [0000-0001-8345-593X], Momose, M [0000-0002-3001-0897], Nakagawa, T [0000-0002-6660-9375], Oh, D [0000-0003-2691-804X], Kudo, T [0000-0002-9294-1793], Brandt, TD [0000-0003-2630-8073], Guyon, O [0000-0002-1097-9908], Hayano, Y [0000-0003-4937-4233], Hodapp, KW [0000-0003-0786-2140], Kandori, R [0000-0003-2610-6367], Knapp, GR [0000-0002-9259-1164], Kwon, J [0000-0003-2815-7774], Miyama, S [0000-0001-5017-180X], Moro-Martin, A [0000-0001-9504-8426], Pyo, TS [0000-0002-3273-0804], Takami, M [0000-0001-9248-7546], Terada, H [0000-0002-7914-6779], Thalmann, C [0000-0002-1664-2177], Watanabe, M [0000-0002-3656-4081], Wisniewski, J [0000-0001-9209-1808], Usuda, T [0000-0001-9855-0163], Tamura, M [0000-0002-6510-0681], and Apollo - University of Cambridge Repository

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Polarimetry, FOS: Physical sciences, Astrophysics, stars: pre-main sequence, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 010309 optics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Adaptive optics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), Physics, binaries: general (T Tau), protoplanetary disks, Astronomy and Astrophysics, Polarization (waves), Position angle, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, stars: variables: T Tauri, Herbig Ae/Be, Outflow, Astrophysics::Earth and Planetary Astrophysics, Circumbinary planet, Subaru Telescope, Astrophysics - Earth and Planetary Astrophysics
Abstract

著者人数: 55名(所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 中川, 貴雄; 權, 靜美), Accepted: 2018-05-18, 資料番号: SA1180099000

Published
2018

7. SCExAO/CHARIS Near-Infrared Direct Imaging, Spectroscopy, and Forward-Modeling of kappa And b: A Likely Young, Low-Gravity Superjovian Companion

Author

Jungmi Kwon, Eugene Serabyn, Timothy D. Brandt, Nour Skaf, Nemanja Jovanovic, Christian Marois, Jun Nishikawa, Markus Janson, Frantz Martinache, Taichi Uyama, Olivier Guyon, Eiji Akiyama, Sean Goebel, Daehyeon Oh, Kyle Mede, Klaus W. Hodapp, M. Hayashi, Motohide Tamura, Thayne Currie, Masayuki Kuzuhara, Joshua E. Schlieder, Jeffrey Chilcote, Julien Lozi, Eric L. Nielsen, Gillian R. Knapp, Ruben Asensio-Torres, N. Jeremy Kasdin, Joseph C. Carson, Carol A. Grady, Michael L. Sitko, Michael W. McElwain, Tyler D. Groff, Sarah Blunt, Département Sciences de la Fabrication et Logistique (SFL-ENSMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-CMP-GC, University of Victoria [Canada] (UVIC), ONERA - The French Aerospace Lab [Palaiseau], ONERA-Université Paris Saclay (COmUE), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), NASA Goddard Space Flight Center (GSFC), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Jet Propulsion Laboratory (JPL), and NASA-California Institute of Technology (CALTECH)

Subjects
FOS: Physical sciences, Direct imaging, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Low Gravity, 010309 optics, 0103 physical sciences, Field spectroscopy, Astrophysics::Solar and Stellar Astrophysics, Spectroscopy, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Solar and Stellar Astrophysics (astro-ph.SR), Physics, [PHYS]Physics [physics], Earth and Planetary Astrophysics (astro-ph.EP), Near-infrared spectroscopy, techniques: high angular resolution, Astronomy and Astrophysics, stars: early-type, Planetary system, planetary system, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, stars: individual: (HD 222439), Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract

著者人数: 33名（所属. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS): 權, 靜美), Accepted: 2018-10-17, 資料番号: SA1180200000

Published
2018
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8. The shadow knows: using shadows to investigate the structure of the pretransitional disk of HD 100453

Author

Jacques Kluska, Misato Fukagawa, Satoshi Mayama, Zachary C. Long, Takayuki Muto, John P. Wisniewski, Taichi Uyama, Rachel B. Fernandes, Stefan Kraus, Kevin Wagner, Michael W. McElwain, Katherine B. Follette, Jun Hashimoto, Michael L. Sitko, Yi Yang, Yasuhiro Hasegawa, Carol A. Grady, Daehyeon Oh, and Motohide Tamura

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010308 nuclear & particles physics, Library science, FOS: Physical sciences, Astronomy and Astrophysics, 01 natural sciences, Space and Planetary Science, Research council, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Subaru Telescope, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present GPI polarized intensity imagery of HD 100453 in Y-, J-, and K1 bands which reveals an inner gap ($9 - 18$ au), an outer disk ($18-39$ au) with two prominent spiral arms, and two azimuthally-localized dark features also present in SPHERE total intensity images (Wagner 2015). SED fitting further suggests the radial gap extends to $1$ au. The narrow, wedge-like shape of the dark features appears similar to predictions of shadows cast by a inner disk which is misaligned with respect to the outer disk. Using the Monte Carlo radiative transfer code HOCHUNCK3D (Whitney 2013), we construct a model of the disk which allows us to determine its physical properties in more detail. From the angular separation of the features we measure the difference in inclination between the disks 45$^{\circ}$, and their major axes, PA = 140$^{\circ}$ east of north for the outer disk and 100$^{\circ}$for the inner disk. We find an outer disk inclination of $25 \pm 10^{\circ}$ from face-on in broad agreement with the Wagner 2015 measurement of 34$^{\circ}$. SPHERE data in J- and H-bands indicate a reddish disk which points to HD 100453 evolving into a young debris disk.

Published
2017

9. Near-infrared imaging polarimetry of LkCa 15: A possible warped inner disk()

Author

Masahiko Hayashi, Carol A. Grady, T. Currie, Markus Feldt, Christian Thalmann, Jun-Ichi Morino, Ryo Kandori, Tomonori Usuda, Michael W. McElwain, Sebastian Egner, Edwin L. Turner, Miwa Goto, Eiji Akiyama, Masanori Iye, Eugene Serabyn, Motohide Tamura, Yasuhiro H. Takahashi, Miki Ishii, Hideki Takami, Gillian R. Knapp, Tetsuo Nishimura, Hiroshi Terada, Thomas Henning, Saeko S. Hayashi, Naruhisa Takato, Lyu Abe, Joseph C. Carson, Tae-Soo Pyo, Masayuki Kuzuhara, Takuya Suenaga, Olivier Guyon, John P. Wisniewski, Toru Yamada, Yutaka Hayano, Daehyeon Oh, Timothy D. Brandt, Wolfgang Brandner, Satoshi Mayama, Tomoyuki Kudo, Michihiro Takami, Shoken Miyama, Markus Janson, Jungmi Kwon, Hiroshi Suto, Makoto Watanabe, Klaus W. Hodapp, Nobuhiko Kusakabe, Ryuji Suzuki, Taro Matsuo, Amaya Moro-Martin, and Jun Hashimoto

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, Polarimetry, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Planetary system, Position angle, 01 natural sciences, Article, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Angular resolution, Near infrared imaging, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Intensity (heat transfer), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present high-contrast H-band polarized intensity images of the transitional disk around the young solar-like star LkCa 15. By utilizing Subaru/HiCIAO for polarimetric differential imaging, both the angular resolution and the inner working angle reach 0.07" and r=0.1", respectively. We obtained a clearly resolved gap (width, Comment: 6 pages, 3 figures, accepted in PASJ on December 14, 2015

Published
2016

10. Near-infrared imaging polarimetry of LkCa 15: A possible warped inner disk.

Author

Daehyeon OH, Jun HASHIMOTO, Motohide TAMURA, WISNIEWSKI, John, Eiji AKIYAMA, CURRIE, Thayne, Satoshi MAYAMA, Michihiro TAKAMI, THALMANN, Christian, Tomoyuki KUDO, Nobuhiko KUSAKABE, Lyu ABE, BRANDNER, Wolfgang, BRANDT, Timothy D., CARSON, Joseph C., EGNER, Sebastian, FELDT, Markus, Miwa GOTO, GRADY, Carol A., and GUYON, Olivier

Subjects
*CIRCUMSTELLAR matter, *PROTOPLANETARY disks, *INFRARED imaging, *POLARIMETRY, *STARS
Abstract

We present high-contrast H-band polarized intensity images of the transitional disk around the young solar-like star LkCa 15. By utilizing Subaru/HiCIAO for polarimetric differential imaging, the angular resolution and the inner working angle reach 0. "07 and r = 0. "1, respectively. We obtained a clearly resolved gap (width ≲27 au) at ~48 au from the central star. This gap is consistent with images reported in previous studies. We also confirmed the existence of a bright inner disk with a misaligned position angle of 13° ±4° with respect to that of the outer disk, i.e., the inner disk is possibly warped. The large gap and the warped inner disk both point to the existence of a multiple planetary system with a mass of ≲1MJup. [ABSTRACT FROM AUTHOR]

Published
2016
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13. High-contrast Polarimetry Observation of the T Tau Circumstellar Environment.

Author

Yi Yang, Satoshi Mayama, Saeko S. Hayashi, Jun Hashimoto, Roman Rafikov, Eiji Akiyama, Thayne Currie, Markus Janson, Munetake Momose, Takao Nakagawa, Daehyeon Oh, Tomoyuki Kudo, Nobuhiko Kusakabe, Lyu Abe, Wolfgang Brandner, Timothy D. Brandt, Joseph C. Carson, Sebastian Egner, Markus Feldt, and Miwa Goto

Subjects
POLARIMETRY, CIRCUMSTELLAR matter, INTERSTELLAR medium, POLARIZATION (Nuclear physics), CIRCUMBINARY planets
Abstract

We conducted high-contrast polarimetry observations of T Tau in the H-band, using the High Contrast Instrument for the Subaru Next Generation Adaptive Optics instrument mounted on the Subaru Telescope, revealing structures as near as 0.″1 from the stars T Tau N and T Tau S. The whole T Tau system is found to be surrounded by nebula-like envelopes, and several outflow-related structures are detected in these envelopes. We analyzed the detailed polarization patterns of the circumstellar structures near each component of this triple young star system and determined constraints on the circumstellar disks and outflow structures. We suggest that the nearly face-on circumstellar disk of T Tau N is no larger than 0.″8, or 117 au, in the northwest, based on the existence of a hole in this direction, and no larger than 0.″27, or 40 au, in the south. A new structure, “N5,” extends to about 0.″42, or 59 au, southwest of the star, and is believed to be part of the disk. We suggest that T Tau S is surrounded by a highly inclined circumbinary disk with a radius of about 0.″3, or 44 au, with a position angle of about 30°, that is misaligned with the orbit of the T Tau S binary. After analyzing the positions and polarization vector patterns of the outflow-related structures, we suggest that T Tau S should trigger the well-known E–W outflow, and is also likely to be responsible for a southwest precessing outflow “coil” and a possible south outflow. [ABSTRACT FROM AUTHOR]

Published
2018
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14. NEAR-INFRARED IMAGING POLARIMETRY OF INNER REGION OF GG TAU A DISK.

Author

Yi Yang, Jun Hashimoto, Saeko S. Hayashi, Motohide Tamura, Satoshi Mayama, Roman Rafikov, Eiji Akiyama, Joseph C. Carson, Markus Janson, Jungmi Kwon, Jerome de Leon, Daehyeon Oh, Michihiro Takami, Ya-wen Tang, Tomoyuki Kudo, Nobuhiko Kusakabe, Lyu Abe, Wolfgang Brandner, Timothy D. Brandt, and Sebastian Egner

Published
2017
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