Mihoko Konishi
A5066751177- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- SAS software applications and methods
- Adaptive optics and wavefront sensing
- Atmospheric Ozone and Climate
- Molecular Spectroscopy and Structure
- Astrophysical Phenomena and Observations
- Spectroscopy and Laser Applications
- Geophysics and Gravity Measurements
- Optical Systems and Laser Technology
- Advanced Measurement and Metrology Techniques
- Space Exploration and Technology
- High-pressure geophysics and materials
- Solar and Space Plasma Dynamics
- Spectroscopy and Chemometric Analyses
- Earthquake Detection and Analysis
- Geography and Environmental Studies in Latin America
- Advanced Fiber Optic Sensors
- Atmospheric aerosols and clouds
- Biomedical and Engineering Education
- Chalcogenide Semiconductor Thin Films
Oita University
2020-2024
University of Hawaii at Hilo
2023
Astrobiology Center
2018-2019
National Institutes of Natural Sciences
2018
National Astronomical Observatory of Japan
2016-2018
Osaka University
1983-2016
Osaka Health Science University
2016
The Infrared Doppler (IRD) instrument is a fiber-fed high-resolution NIR spectrometer for the Subaru telescope covering Y,J,H-bands simultaneously with maximum spectral resolution of 70,000. main purpose IRD search Earth-mass planets around nearby M-dwarfs by precise radial velocity measurements, as well spectroscopic characterization exoplanet atmospheres. We report current status instrument, which undergoing commissioning at Telescope, and first light observation successfully done in...
We report a new evaluation of the accretion properties PDS~70b obtained with VLT/MUSE. The main difference from previous studies in Haffert et al. (2019) and Aoyama & Ikoma is mass rate. Simultaneous multiple line observations, such as H$\alpha$ H$\beta$, can better constrain physical an accreting planet. While we clearly detected emissions PDS~70b, no H$\beta$ were detected. estimate flux 3-$\sigma$ upper limit to be 2.3~$\times$~10$^{-16}$~erg~s$^{-1}$~cm$^{-2}$. ratio $F_{\rm...
We obtained spectra of the pre-main sequence star AU Microscopii during a transit its Neptune-sized planet to investigate orbit and atmosphere. used high-dispersion near-infrared spectrograph IRD on Subaru telescope detect Doppler "shadow" from constrain projected stellar obliquity. Modeling observed planetary shadow suggests spin-orbit alignment system ($\lambda=-4.7_{-6.4}^{+6.8}$ degrees), but additional observations are needed confirm this finding. use both data with NIRSPEC Keck-II...
Context . Previous high-angular-resolution 225 GHz (~1.3 mm) continuum observations of the transitional disk DM Tau have resolved an outer ring at 20–120 au radii that is weakly azimuthally asymmetric. Aims We aim to examine dust growth and filtration in Tau. Methods performed ~0″.06 (~8.7 au) resolution Karl G. Jansky Very Large Array (JVLA) 40–48 (~7 mm; Q band) observations, along with complementary lower frequencies. In addition, we analyzed archival JVLA undertaken since 2010. Results...
We carried out an imaging survey for extrasolar planets around stars in the Pleiades (125 Myr, 135 pc) $H$ and $K_{S}$ bands using HiCIAO combined with adaptive optics, AO188, on Subaru telescope. found 13 companion candidates fainter than 14.5 mag band 9 stars. Five of these were confirmed to be background by measurement their proper motion. One was not second epoch observation, thus a or object. had multi-epoch image, but precision its motion sufficient conclude whether it Four other are...
We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the dust continuum emission at 1.3 mm and 12CO J=2-1 line transitional disk around DM Tau. Tau's is thought to possess a dust-free inner cavity inside few au, from absence near-infrared excess on its spectral energy distribution (SED). Previous submillimeter were, however, unable detect cavity; instead, ring ~20 au in radius was seen. The excellent angular resolution achieved new ALMA observations, 43 x 31 mas,...
We obtained high-resolution infrared spectroscopy and short-cadence photometry of the 600-800 Myr Praesepe star K2-100 during transits its 1.67-day planet. This Neptune-size object, discovered by NASA K2 mission, is an interloper in "desert" planets with similar radii on short period orbits. Our observations can be used to understand origin evolution constraining orbital eccentricity transit fitting, measuring spin-orbit obliquity Rossiter-McLaughlin effect, detecting any extended, escaping...
Recent discoveries of Earth-sized planets transiting nearby M dwarfs have made it possible to characterize the atmospheres terrestrial via follow-up spectroscopic observations. However, number such receiving low insolation is still small, limiting our ability understand diversity atmospheric composition and climates temperate planets. We report discovery an planet (12 pc) inactive M3.0 dwarf Gliese 12 (TOI-6251) with orbital period ($P_{\rm{orb}}$) 12.76 days. The planet, 12b, was initially...
ABSTRACT We report the discovery of a scattering component around HD 141569 A circumstellar debris system, interior to previously known inner ring. The discovered disk component, obtained in broadband optical light with Hubble Space Telescope /Space Imaging Spectrograph coronagraphy, was imaged an working angle 0.″25, and can be traced from 0.″4 (∼46 AU) 1.″0 (∼116 after deprojection using i = 55°. is seen forward scatter manner similar rings, has pericenter offset ∼6 AU, break points where...
Abstract We obtained high-resolution spectra of the ultracool M-dwarf TRAPPIST-1 during transit its planet “b” using two high-dispersion near-infrared spectrographs, Infrared Doppler (IRD) instrument on Subaru 8.2m telescope, and Habitable Zone Planet Finder (HPF) 10 m Hobby–Eberly Telescope. These spectroscopic observations are complemented by a photometric observation for APO/ARCTIC, which assisted us in capturing correct times our spectroscopy. Using data new IRD HPF observations, as well...
Studies of planetary systems stars in star-forming regions and young clusters open a window on the formative stages evolution. We obtained high-cadence high-resolution infrared spectroscopy solar-mass Taurus association-member V1298 Tau during transit its 10R$_{\oplus}$-size "b" planet. measured systemic radial velocity find that kinematics suggest an affiliation with $\gtrsim$6 Myr-old subgroup. A comparison nearby, co-moving star 2M0405 stellar evolution models suggests age $\sim$10-25...
\textit{Kepler} showed a paucity of planets with radii 1.5 - 2 $\mathrm R_{\oplus}$ around solar mass stars but this radius-gap has not been well studied for low-mass star planets. Energy-driven escape models like photoevaporation and core-powered mass-loss predict opposing transition regimes between rocky non-rocky when compared to depicting forming in gas-poor environments. Here we present transit observations three super-Earth sized the using high-dispersion InfraRed Doppler (IRD)...
In this study, we reported the results of high-resolution (0.14 arcsec) Atacama Large Millimeter/submillimeter Array (ALMA) observations 225 GHz dust continuum and CO molecular emission lines from transitional disk around SY Cha. Our clearly revealed inner cavity central point source for first time. The radial profile ring can be approximated by a bright narrow superimposed on fainter wide ring. Furthermore, found that there is weak azimuthal asymmetry in emission. For gas emissions,...
Abstract Individual vibrational band spectroscopy presents an opportunity to examine exoplanet atmospheres in detail, by distinguishing where the state populations of molecules differ from current assumption a Boltzmann distribution. Here, retrieving bands OH is explored using hot Jupiter WASP-33b as example. We simulate low-resolution spectroscopic data for observations with JWST's NIRSpec instrument and use high-resolution observational obtained Subaru InfraRed Doppler (IRD). Vibrational...
M dwarf stars are high-priority targets for searches Earth-size and potentially Earth-like planets, but their planetary systems may form evolve in very different circumstellar environments than those of solar-type stars. To explore the evolution these systems, we obtained transit spectroscopy photometry Neptune-size planet orbiting ~650 Myr-old Hyades K2-25. An analysis variation spectral line shape induced by Doppler "shadow" indicate that planet's orbit is closely aligned with stellar...
Abstract We report the near-infrared radial velocity (RV) discovery of a super-Earth planet on 10.77 d orbit around M4.5 dwarf Ross 508 (Jmag = 9.1). Using precision RVs from Subaru Telescope IRD (InfraRed Doppler) instrument, we derive semi-amplitude $3.92^{+0.60}_{-0.58}\:\mbox{m}\:{\mbox{s}^{-1}}$, corresponding to with minimum mass $m \sin i 4.00^{+0.53}_{-0.55}\, M_{\oplus }$. find no evidence significant signals at detected period in spectroscopic stellar activity indicators or MEarth...
Using Keck/NIRC2 $L^\prime$ (3.78 $\mu m$) data, we report the direct imaging discovery of a scattered light-resolved, solar system-scale residual protoplanetary disk around young A-type star HD 141569A, interior to and concentric with two ring-like structures at wider separations. The is resolved down $\sim$ 0\farcs{}25 appears as an arc-like rim attached hook-like features. It located angular separation intermediate between that warm CO gas identified from spatially-resolved mid-infrared...
Abstract In an effort to measure the Rossiter–McLaughlin effect for TRAPPIST-1 system, we performed high-resolution spectroscopy during transits of planets e, f, and b. The spectra were obtained with InfraRed Doppler spectrograph on Subaru 8.2 m telescope, supplemented simultaneous photometry a 1 telescope Las Cumbres Observatory Global Telescope. By analyzing anomalous radial velocities, found projected stellar obliquity be λ = ± 28° under assumption that three have coplanar orbits,...
Abstract We present Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 observations of dust continuum emission the disk around WW Cha. The image shows a smooth structure with faint (low-contrast) ring, extending from ∼40 au to ∼70 au, not accompanied by any gap. constructed simple model fit visibility observed data using Markov Chain Monte Carlo (MCMC) method and found that bump (we call ring without gap bump) has two peaks at 40 70 au. residual map between observation indicates...
The InfraRed Doppler (IRD) instrument is a high-dispersion spectrograph that available on Subaru Telescope to explore extrasolar planets via infrared radial velocity (RV) observations. Subaru/IRD especially useful in the search of low-mass planet around cool M-type dwarfs for which RV observations are essential. We report our early performance tests IRD. IRD's two H2RG detectors have been evaluated with detector readout technique, ensuring their noise made sufficiently smaller than stellar...
GW Ori is a hierarchical triple system which has rare circumtriple disk. We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of 1.3 mm dust continuum and 12CO J=2-1 molecular gas emission the For first time, we identify three rings in disk at ~46, 188, 338 AU, with estimated mass ~70-250 Earth masses, respectively. To our knowledge, outer ring largest ever found protoplanetary disks. use visibility modelling to show that misaligned parts innermost eccentric. The...
The NASA space telescope $TESS$ is currently in the extended mission of its all-sky search for new transiting planets. Of thousands candidates that TESS expected to deliver, planets orbiting nearby M dwarfs are particularly interesting targets since they provide a great opportunity characterize their atmospheres by transmission spectroscopy. We aim validate and sub-Neptune-sized planet candidate TOI-2136.01 dwarf ($d = 33.36 \pm 0.02$ pc, $T_{eff} 3373 108$ K) with an orbital period 7.852...
Abstract The powerful, high-energy magnetic activities of young stars play important roles in the magnetohydrodynamics innermost parts protoplanetary disks. In addition, associated UV and X-ray emission dictates photochemistry; moreover, corona can affect atmosphere a newborn extrasolar planet. How photons are generated how they illuminate disks not well understood. Here we report analyses optical infrared (OIR) photometric monitoring observations high angular resolution centimeter-band...
Abstract Sub-Neptunes with radii of 2–3 R ⊕ are intermediate in size between rocky planets and Neptune-sized planets. The orbital properties bulk compositions transiting sub-Neptunes provide clues to the formation evolution close-in small In this paper, we present discovery follow-up four orbiting M dwarfs (TOI-782, TOI-1448, TOI-2120, TOI-2406), three which were newly validated by ground-based observations statistical analyses. TOI-782 b, TOI-1448 TOI-2120 TOI-2406 b have <mml:math...
We compared the number of faint stars detected in deep survey fields with current stellar distribution model Galaxy and found that H band is significantly smaller than predicted number. This indicates M-dwarfs, major component, are fewer halo thick disk. used archived data several surveys both north south field GOODS (Great Observatories Origins Deep Survey), MODS GOODS-N, ERS CANDELS GOODS-S. The density M-dwarfs has to be 20+/-13% relative solar vicinity, order for fainter 20.5 mag match...