arXiv subjects

Tomoyuki Kudo

Publications and source records attributed to Tomoyuki Kudo.

At least 37 records · Page 2Linked to original sources

arXiv2023

Absence of extended atmospheres in low-mass star radius-gap planets GJ 9827 b, GJ 9827 d and TOI-1235 b

\textit{Kepler} showed a paucity of planets with radii of 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 and non-rocky planets when compared to models depicting planets forming in gas-poor environments. Here we present transit observations of three super-Earth sized planets in the radius-gap around low-mass stars using high-dispersion InfraRed Doppler (IRD) spectrograph on the Subaru 8.2m telescope. The planets GJ 9827 b and d orbit around a K6V star and TOI-1235 b orbits a M0.5 star. We limit any planet-related absorption in the 1083.3 nm lines of triplet He I by placing an upper-limit on the equivalent width of 14.71 mÅ, 18.39 mÅ, and 1.44 mÅ, for GJ 9827 b (99% confidence), GJ 9827 d (99% confidence) and TOI-1235 b (95% confidence) respectively. Using a Parker wind model, we cap the mass-loss at $>$0.25 $\mathrm M_{\oplus}$ Gyr$^{-1}$ and $>$0.2 $\mathrm M_{\oplus}$ Gyr$^{-1}$ for GJ 9827 b and d, respectively (99% confidence), and $>$0.05 $\mathrm M_{\oplus}$ Gyr$^{-1}$ for TOI-1235 b (95\% confidence) for a representative wind temperature of 5000 K. Our observed results for the three planets are more consistent with the predictions from photoevaporation and/or core-powered mass-loss models than the gas-poor formation models. However, more planets in the radius-gap regime around the low-mass stars are needed to robustly predict the atmospheric evolution in planets around low-mass stars.

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arXiv2023

Direct Imaging Explorations for Companions around Mid-Late M Stars from the Subaru/IRD Strategic Program

The Subaru telescope is currently performing a strategic program (SSP) using the high-precision near-infrared (NIR) spectrometer IRD to search for exoplanets around nearby mid/late-M~dwarfs via radial velocity (RV) monitoring. As part of the observing strategy for the exoplanet survey, signatures of massive companions such as RV trends are used to reduce the priority of those stars. However, this RV information remains useful for studying the stellar multiplicity of nearby M~dwarfs. To search for companions around such ``deprioritized" M~dwarfs, we observed 14 IRD-SSP targets using Keck/NIRC2 observations with pyramid wavefront sensing at NIR wavelengths, leading to high sensitivity to substellar-mass companions within a few arcseconds. We detected two new companions (LSPM~J1002+1459~B and LSPM~J2204+1505~B) and two new candidates that are likely companions (LSPM~J0825+6902~B and LSPM~J1645+0444~B) as well as one known companion. Including two known companions resolved by the IRD fiber injection module camera, we detected seven (four new) companions at projected separations between $\sim2-20$~au in total. A comparison of the colors with the spectral library suggests that LSPM~J2204+1505~B and LSPM~J0825+6902~B are located at the boundary between late-M and early-L spectral types. Our deep high-contrast imaging for targets where no bright companions were resolved did not reveal any additional companion candidates. The NIRC2 detection limits could constrain potential substellar-mass companions ($\sim10-75\ M_{\rm Jup}$) at 10~au or further. The failure with Keck/NIRC2 around the IRD-SSP stars having significant RV trends makes these objects promising targets for further RV monitoring or deeper imaging with JWST to search for smaller-mass companions below the NIRC2 detection limits.

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arXiv2023

ALMA Band 6 high-resolution observations of the transitional disk around SY Cha

In this study, we reported the results of high-resolution (0.14 arcsec) Atacama Large Millimeter/submillimeter Array (ALMA) observations of the 225 GHz dust continuum and CO molecular emission lines from the transitional disk around SY Cha. Our high-resolution observations clearly revealed the inner cavity and the central point source for the first time. The radial profile of the ring can be approximated by a bright narrow ring superimposed on a fainter wide ring. Furthermore, we found that there is a weak azimuthal asymmetry in dust continuum emission. For gas emissions, we detected $\rm{}^{12}CO$(2$-$1), $\rm{}^{13}CO$(2$-$1) and $\rm{}C^{18}O$(2$-$1), from which we estimated the total gas mass of the disk to be $2.2\times10^{-4}M_\odot$, assuming a CO/H$_2$ ratio of $10^{-4}$. The observations showed that the gas is present inside the dust cavity. The analysis of the velocity structure of the $\rm{}^{12}CO$(2$-$1) emission line revealed that the velocity is distorted at the location of the dust inner disk, which may be owing to warping of the disk or radial gas flow within the cavity of the dust disk. High-resolution observations of SY Cha showed that this system is composed of a ring and a distorted inner disk, which may be common, as indicated by the survey of transitional disk systems at a resolution of $\sim$0.1~arcsec.

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arXiv2023

An Earth-sized Planet around an M5 Dwarf Star at 22 pc

We report on the discovery of an Earth-sized transiting planet ($R_p=1.015\pm0.051\,R_\oplus$) in a $P=4.02$ day orbit around K2-415 (EPIC 211414619), an M5V star at 22 pc. The planet candidate was first identified by analyzing the light curve data by the K2 mission, and is here shown to exist in the most recent data from TESS. Combining the light curves with the data secured by our follow-up observations including high-resolution imaging and near infrared spectroscopy with IRD, we rule out false positive scenarios, finding a low false positive probability of $2\times 10^{-4}$. Based on IRD's radial velocities of K2-415, which were sparsely taken over three years, we obtain the planet mass of $3.0\pm 2.7\,M_\oplus$ ($M_p<7.5\,M_\oplus$ at $95\,\%$ confidence) for K2-415b. Being one of the lowest mass stars ($\approx 0.16\,M_\odot$) known to host an Earth-sized transiting planet, K2-415 will be an interesting target for further follow-up observations, including additional radial velocity monitoring and transit spectroscopy.

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arXiv2022

Planet(esimal)s Around Stars with TESS (PAST) III: A Search for Triplet He I in the Atmospheres of Two 200 Myr-old Planets

We report a search for excess absorption in the 1083.2 nm line of ortho (triplet) helium during transits of TOI-1807b and TOI-2076b, 1.25 and 2.5R$_{\rm Earth}$ planets on 0.55- and 10.4-day orbits around nearby $\sim$200~Myr-old K dwarf stars. We limit the equivalent width of any transit-associated absorption to $<$4 and $<$8 mA, respectively. We limit the escape of solar-composition atmospheres from TOI-1807b and TOI-2076b to $\lesssim$1 and $\lesssim$0.1M$_{\rm Earth}$ Gyr$^{-1}$, respectively, depending on wind temperature. The absence of a H/He signature for TOI-1807b is consistent with a measurement of mass indicating a rocky body and the prediction by a hydrodynamic model that any H-dominated atmosphere would be unstable and already have been lost. Differential spectra obtained during the transit of TOI-2076b contain a He I-like feature, but this closely resembles the stellar line and extends beyond the transit interval. Until additional transits are observed, we suspect this to be the result of variation in the stellar He I line produced by rotation of active regions and/or flaring on the young, active host star. Non-detection of escape could mean that TOI-2076b is more massive than expected, the star is less EUV-luminous, the models overestimate escape, or the planet has a H/He-poor atmosphere that is primarily molecules such as H$_2$O. Photochemical models of planetary winds predict a semi-major axis at which triplet He I observations are most sensitive to mass loss: TOI-2076b orbits near this optimum. Future surveys could use a distance criterion to increase the yield of detections.

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arXiv2022

High Contrast and High Angular Imaging at Subaru Telescope

Adaptive Optics projects at Subaru Telescope span a wide field of capabilities ranging from ground-layer adaptive optics (GLAO) providing partial correction over a 20 arcmin FOV to extreme adaptive optics (ExAO) for exoplanet imaging. We describe in this paper current and upcoming narrow field-of-view capabilities provided by the Subaru Extreme Adaptive Optics Adaptive Optics (SCExAO) system and its instrument modules, as well as the upcoming 3000-actuator upgrade of the Nasmyth AO system.

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arXiv2022

Direct Imaging Discovery and Dynamical Mass of a Substellar Companion Orbiting an Accelerating Hyades Sun-like Star with SCExAO/CHARIS

We present the direct-imaging discovery of a substellar companion in orbit around a Sun-like star member of the Hyades open cluster. So far, no other substellar companions have been unambiguously confirmed via direct imaging around main-sequence stars in Hyades. The star HIP 21152 is an accelerating star as identified by the astrometry from the Gaia and Hipparcos satellites. We have detected the companion, HIP 21152 B, in multi-epoch using the high-contrast imaging from SCExAO/CHARIS and Keck/NIRC2. We have also obtained the stellar radial-velocity data from the Okayama 188cm telescope. The CHARIS spectroscopy reveals that HIP 21152 B's spectrum is consistent with the L/T transition, best fit by an early T dwarf. Our orbit modeling determines the semi-major axis and the dynamical mass of HIP 21152 B to be 17.5$^{+7.2}_{-3.8}$ au and 27.8$^{+8.4}_{-5.4}$ $M_{\rm{Jup}}$, respectively. The mass ratio of HIP 21152 B relative to its host is $\approx$2\%, near the planet/brown dwarf boundary suggested from recent surveys. Mass estimates inferred from luminosity evolution models are slightly higher (33--42 $M_{\rm{Jup}}$). With a dynamical mass and a well-constrained age due to the system's Hyades membership, HIP 21152 B will become a critical benchmark in understanding the formation, evolution, and atmosphere of a substellar object as a function of mass and age. Our discovery is yet another key proof-of-concept for using precision astrometry to select direct imaging targets.

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arXiv2022

A Super-Earth Orbiting Near the Inner Edge of the Habitable Zone around the M4.5-dwarf Ross 508

We report the near-infrared radial-velocity (RV) discovery of a super-Earth planet on a 10.77-day orbit around the M4.5 dwarf Ross 508 ($J_\mathrm{mag}=9.1$). Using precision RVs from the Subaru Telescope IRD (InfraRed Doppler) instrument, we derive a semi-amplitude of $3.92^{+0.60}_{-0.58}$ ${\rm m\,s}^{-1}$, corresponding to a planet with a minimum mass $m \sin i = 4.00^{+0.53}_{-0.55}\ M_{\oplus}$. We find no evidence of significant signals at the detected period in spectroscopic stellar activity indicators or MEarth photometry. The planet, Ross 508 b, has a semimajor-axis of $0.05366^{+0.00056}_{-0.00049}$ au. This gives an orbit-averaged insolation of $\approx$1.4 times the Earth's value, placing Ross 508 b near the inner edge of its star's habitable zone. We have explored the possibility that the planet has a high eccentricity and its host is accompanied by an additional unconfirmed companion on a wide orbit. Our discovery demonstrates that the near-infrared RV search can play a crucial role to find a low-mass planet around cool M dwarfs like Ross 508.

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arXiv2022

Images of Embedded Jovian Planet Formation At A Wide Separation Around AB Aurigae

Direct images of protoplanets embedded in disks around infant stars provide the key to understanding the formation of gas giant planets like Jupiter. Using the Subaru Telescope and Hubble Space Telescope, we find evidence for a jovian protoplanet around AB Aurigae orbiting at a wide projected separation (93 au), likely responsible for multiple planet-induced features in the disk. Its emission is reproducible as reprocessed radiation from an embedded protoplanet. We also identify two structures located at 430-580 au that are candidate sites of planet formation. These data reveal planet formation in the embedded phase and a protoplanet discovery at wide, > 50 au separations characteristic of most imaged exoplanets. With at least one clump-like protoplanet and multiple spiral arms, the AB Aur system may also provide the evidence for a long-considered alternative to the canonical model for Jupiter's formation: disk (gravitational) instability.

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arXiv2022

TOI-1696: a nearby M4 dwarf with a $3R_\oplus$ planet in the Neptunian desert

We present the discovery and validation of a temperate sub-Neptune around the nearby mid-M dwarf TIC 470381900 (TOI-1696), with a radius of $3.09 \pm 0.11 \,R_\oplus$ and an orbital period of $2.5 \,\rm{days}$, using a combination of TESS and follow-up observations using ground-based telescopes. Joint analysis of multi-band photometry from TESS, MuSCAT, MuSCAT3, Sinistro, and KeplerCam confirmed the transit signal to be achromatic as well as refined the orbital ephemeris. High-resolution imaging with Gemini/'Alopeke and high-resolution spectroscopy with the Subaru/IRD confirmed that there are no stellar companions or background sources to the star. The spectroscopic observations with IRD and IRTF/SpeX were used to determine the stellar parameters, and found the host star is an M4 dwarf with an effective temperature of $T_{eff} = 3185 \pm 76\,\rm{K}$ and a metallicity of [Fe/H] $=0.336 \pm 0.060 \,\rm{dex}$. The radial velocities measured from IRD set a $2$-$σ$ upper limit on the planetary mass to be $48.8 \,M_\oplus$. The large radius ratio ($R_p/R_\star \sim 0.1$) and the relatively bright NIR magnitude ($J=12.2 \,\rm{mag}$) make this planet an attractive target for further followup observations. TOI-1696b is one of the planets belonging to the Neptunian desert with the highest transmission spectroscopy metric discovered to date, making it an interesting candidate for atmospheric characterizations with JWST.

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arXiv2021

Silicon and Strontium abundances of very metal-poor stars determined from near-infrared spectra

Silicon and Strontium are key elements to explore the nucleosynthesis and chemical evolution of the Galaxy by measurements of very metal-poor stars. There are, however, only a few useful spectral lines of these elements in the optical range that are measurable for such low-metallicity stars. Here we report on abundances of these two elements determined from near-infrared high-resolution spectra obtained with the Subaru Telescope Infrared Doppler instrument (IRD). Si abundances are determined for as many as 26 Si lines for six very and extremely metal-poor stars (-4.0<[Fe/H]<-1.5), which significantly improves the reliability of the abundance measurements. All six stars, including three carbon-enhanced objects, show over-abundances of Si ([Si/Fe]~+0.5). Two stars with [Fe/H]~-1.5 have relatively small over-abundances. The [Mg/Si] ratios agree with the solar value, except for one metal-poor star with carbon excess. Strontium abundances are determined from the triplet lines for four stars, including two for the first time. The consistency of the Sr abundances determined from near-infrared and optical spectra require further examination from additional observations.

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arXiv2021

Elemental abundances of nearby M dwarfs based on high-resolution near-infrared spectra obtained by the Subaru/IRD survey: Proof of concept

Detailed chemical analyses of M dwarfs are scarce but necessary to constrain the formation environment and internal structure of planets being found around them. We present elemental abundances of 13 M dwarfs (2900 < Teff < 3500 K) observed in the Subaru/IRD planet search project. They are mid-to-late M dwarfs whose abundance of individual elements has not been well studied. We use the high-resolution (~70,000) near-infrared (970-1750 nm) spectra to measure the abundances of Na, Mg, Si, K, Ca, Ti, V, Cr, Mn, Fe, and Sr by the line-by-line analysis based on model atmospheres, with typical errors ranging from 0.2 dex for [Fe/H] to 0.3-0.4 dex for other [X/H]. We measure radial velocities from the spectra and combine them with Gaia astrometry to calculate the Galactocentric space velocities UVW. The resulting [Fe/H] values agree with previous estimates based on medium-resolution K-band spectroscopy, showing a wide distribution of metallicity (-0.6 < [Fe/H] < +0.4). The abundance ratios of individual elements [X/Fe] are generally aligned with the solar values in all targets. While the [X/Fe] distributions are comparable to those of nearby FGK stars, most of which belong to the thin disk population, the most metal-poor object, GJ 699, could be a thick disk star. The UVW velocities also support this. The results raise the prospect that near-infrared spectra of M dwarfs obtained in the planet search projects can be used to grasp the trend of elemental abundances and Galactic stellar population of nearby M dwarfs.

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arXiv2021

Full characterization of the instrumental polarization effects of the spectropolarimetric mode of SCExAO-CHARIS

SCExAO at the Subaru telescope is a visible and near-infrared high-contrast imaging instrument employing extreme adaptive optics and coronagraphy. The instrument feeds the near-infrared light (JHK) to the integral-field spectrograph CHARIS. The spectropolarimetric capability of CHARIS is enabled by a Wollaston prism and is unique among high-contrast imagers. We present a detailed Mueller matrix model describing the instrumental polarization effects of the complete optical path, thus the telescope and instrument. From measurements with the internal light source, we find that the image derotator (K-mirror) produces strongly wavelength-dependent crosstalk, in the worst case converting ~95% of the incident linear polarization to circularly polarized light that cannot be measured. Observations of an unpolarized star show that the magnitude of the instrumental polarization of the telescope varies with wavelength between 0.5% and 1%, and that its angle is exactly equal to the altitude angle of the telescope. Using physical models of the fold mirror of the telescope, the half-wave plate, and the derotator, we simultaneously fit the instrumental polarization effects in the 22 wavelength bins. Over the full wavelength range, our model currently reaches a total polarimetric accuracy between 0.08% and 0.24% in the degree of linear polarization. We propose additional calibration measurements to improve the polarimetric accuracy to <0.1% and plan to integrate the complete Mueller matrix model into the existing CHARIS post-processing pipeline. Our calibrations of CHARIS' spectropolarimetric mode will enable unique quantitative polarimetric studies of circumstellar disks and planetary and brown dwarf companions.

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arXiv2021

Two Bright M Dwarfs Hosting Ultra-Short-Period Super-Earths with Earth-like Compositions

We present observations of two bright M dwarfs (TOI-1634 and TOI-1685: $J=9.5-9.6$) hosting ultra-short period (USP) planets, identified by the TESS mission. The two stars are similar in temperature, mass, and radius ($T_\mathrm{eff}\,\approx\,3500$ K, $M_\star\,\approx\,0.45-0.46\,M_\odot$, and $R_\star\approx 0.45-0.46\,R_\odot$), and the planets are both super-Earth-sized ($1.25\,R_\oplus<R_p<2.0\,R_\oplus$). For both systems, light curves from the ground-based photometry exhibit planetary transits, whose depths are consistent with those by the TESS photometry. We also refine the transit ephemerides based on the ground-based photometry, finding the orbital periods of $P=0.9893436\pm0.0000020$ day and $P=0.6691416\pm0.0000019$ day for TOI-1634b and TOI-1685b, respectively. Through intensive radial velocity (RV) observations using IRD on the Subaru 8.2m telescope, we confirm the planetary nature of the TOIs, and measure their masses: $10.14\pm0.95\,M_\oplus$ and $3.43\pm0.93\,M_\oplus$ for TOI-1634b and TOI-1685b, respectively, when the observed RVs are fitted with a single-planet circular-orbit model. Combining those with the planet radii of $R_p=1.749\pm 0.079\,R_\oplus$ (TOI-1634b) and $1.459\pm0.065\,R_\oplus$ (TOI-1685b), we find that both USP planets have mean densities consistent with an Earth-like internal composition, which is typical for small USP planets. TOI-1634b is currently the most massive USP planet in this category, and it resides near the radius valley, which makes it a benchmark planet in the context of discussing the size limit of rocky planet cores as well as testing the formation scenarios for USP planets. Excess scatter in the RV residuals for TOI-1685 suggests the presence of a possible secondary planet or unknown activity/instrumental noise in the RV data, but further observations are required to check those possibilities.

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arXiv2021

Non-detection of Helium in the upper atmospheres of TRAPPIST-1b, e and f

We obtained high-resolution spectra of the ultra-cool M-dwarf TRAPPIST-1 during the transit of its planet `b' using two high dispersion near-infrared spectrographs, IRD instrument on the Subaru 8.2m telescope and HPF instrument on the 10m Hobby-Eberly Telescope. These spectroscopic observations are complemented by a photometric transit observation for planet `b' using the APO/ARCTIC, which assisted us to capture the correct transit times for our transit spectroscopy. Using the data obtained by the new IRD and HPF observations, as well as the prior transit observations of planets `b', `e' and `f' from IRD, we attempt to constrain the atmospheric escape of the planet using the He I triplet 10830 Å absorption line. We do not detect evidence for any primordial extended H-He atmospheres in all three planets. To limit any planet related absorption, we place an upper limit on the equivalent widths of <7.754 mÅ for planet `b', <10.458 mÅ for planet `e', and <4.143 mÅ for planet `f' at 95% confidence from the IRD data, and <3.467 mÅ for planet `b' at 95% confidence from HPF data. Using these limits along with a solar-like composition isothermal Parker wind model, we attempt to constrain the mass-loss rates for the three planets. For TRAPPIST-1b, our models exclude the highest possible energy-limited rate for a wind temperature <5000 K. This non-detection of extended atmospheres having low mean-molecular weight in all three planets aids in further constraining their atmospheric composition by steering the focus towards the search of high molecular weight species in their atmospheres.

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arXiv2021

First Detection of Hydroxyl Radical Emission from an Exoplanet Atmosphere: High-dispersion Characterization of WASP-33b using Subaru/IRD

We report the first detection of a hydroxyl radical (OH) emission signature in the planetary atmosphere outside the solar system, in this case, in the day-side of WASP-33b. We analyze high-resolution near-infrared emission spectra of WASP-33b taken using the InfraRed Doppler spectrograph on the 8.2-m Subaru telescope. The telluric and stellar lines are removed using a de-trending algorithm, SysRem. The residuals are then cross-correlated with OH and H$_{2}$O planetary spectrum templates produced using several different line-lists. We check and confirm the accuracy of OH line-lists by cross-correlating with the spectrum of GJ 436. As a result, we detect the emission signature of OH at $K_\mathrm{p}$ of 230.9$^{+6.9}_{-7.4}$ km s$^{-1}$ and $v_{\mathrm{sys}}$ of $-$0.3$^{+5.3}_{-5.6}$ km s$^{-1}$ with S/N of 5.4 and significance of 5.5$σ$. Additionally, we marginally detect H$_{2}$O emission in the H-band with S/N of 4.0 and significance of 5.2$σ$ using the POKAZATEL line-list. However, no significant signal is detected using the HITEMP 2010, which might be due to differences in line positions and strengths, as well as the incompleteness of the line-lists. Nonetheless, this marginal detection is consistent with the prediction that H$_{2}$O is mostly thermally dissociated in the upper atmosphere of the ultra-hot Jupiters. Therefore, along with CO, OH is expected to be one of the most abundant O-bearing molecules in the day-side atmosphere of ultra-hot Jupiters and should be considered when studying their atmosphere.

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arXiv2020

Calibration of the instrumental polarization effects of SCExAO-CHARIS' spectropolarimetric mode

SCExAO at the Subaru telescope is a visible and near-infrared high-contrast imaging instrument employing extreme adaptive optics and coronagraphy. The instrument feeds the near-infrared light (JHK) to the integral field spectrograph CHARIS. Recently, a Wollaston prism was added to CHARIS' optical path, giving CHARIS a spectropolarimetric capability that is unique among high-contrast imaging instruments. We present a detailed Mueller matrix model describing the instrumental polarization effects of the complete optical path, thus the telescope and instrument. The 22 wavelength bins of CHARIS provide a unique opportunity to investigate in detail the wavelength dependence of the instrumental polarization effects. From measurements with the internal light source, we find that the image derotator (K-mirror) produces strong wavelength-dependent crosstalk, in the worst case converting ~95% of the incident linear polarization to circularly polarized light that cannot be measured. Theoretical calculations show that the magnitude of the instrumental polarization of the telescope varies with wavelength between approximately 0.5% and 0.7%, and that its angle is exactly equal to the altitude angle of the telescope. We plan to more accurately determine the instrumental polarization of the telescope with observations of a polarization standard star, and fit more comprehensive physical models to all experimental data. In addition, we plan to integrate the complete Mueller matrix model into the existing CHARIS post-processing pipeline, with the aim to achieve a polarimetric accuracy of <0.1% in the degree of linear polarization. Our calibrations of CHARIS' spectropolarimetric mode will enable unique quantitative polarimetric studies of circumstellar disks and planetary and brown dwarf companions.

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arXiv2020

High-contrast H$α$ imaging with Subaru/SCExAO+VAMPIRES

We present current status of H$α$ high-contrast imaging observations with Subaru/SCExAO+VAMPIRES. Our adaptive optics correction at optical wavelengths in combination with (double) spectral differential imaging (SDI) and angular differential imaging (ADI) was capable of detecting a ring-like feature around omi Cet and the H$α$ counterpart of jet around RY Tau. We tested the post-processing by changing the order of ADI and SDI and both of the contrast limits achieved $\sim10^{-3}-5\times10^{-4}$ at $0.3^{\prime\prime}$, which is comparable to other H$α$ high-contrast imaging instruments in the southern hemisphere such as VLT/SPHERE, VLT/MUSE, and MagAO. Subaru/VAMPIRES provides great opportunities for H$α$ high-contrast imaging for northern hemisphere targets.

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