activity
20182022
most citedLimits on the Spin-Orbit Angle and Atmospheric Escape for the 22 Myr-old Planet AU Mic b

75 citations · 396 across the 11 of their papers we have counts for

collaborators

11 papers

astro-ph.IM2022★ 7 cited

Coronagraph Experiment on Dark-hole Control by Speckle Area Nulling Method

Masahito Oya, Jun Nishikawa, Masaaki Horie +7

In high-contrast imaging optical systems for direct observation of planets outside our solar system, adaptive optics with an accuracy of lambda/10,000 root mean square is required…

astro-ph.SR2021★ 30 cited

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

Hiroyuki Tako Ishikawa, Wako Aoki, Teruyuki Hirano +24

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 element…

astro-ph.EP2021★ 17 cited

TOI-2285b: A 1.7 Earth-radius Planet Near the Habitable Zone around a Nearby M Dwarf

Akihiko Fukui, Tadahiro Kimura, Teruyuki Hirano +60

We report the discovery of TOI-2285b, a sub-Neptune-sized planet transiting a nearby (42 pc) M dwarf with a period of 27.3 days. We identified the transit signal from the Transitin…

astro-ph.EP2021★ 74 cited

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

Stevanus K. Nugroho, Hajime Kawahara, Neale P. Gibson +23

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 anal…

astro-ph.EP2021★ 2 cited

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

Teruyuki Hirano, John H. Livingston, Akihiko Fukui +58

We present observations of two bright M dwarfs (TOI-1634 and TOI-1685: ) hosting ultra-short period (USP) planets, identified by the TESS mission. The two stars are simi…

astro-ph.EP2020★ 61 cited

Precision radial velocity measurements by the forward-modeling technique in the near-infrared

Teruyuki Hirano, Masayuki Kuzuhara, Takayuki Kotani +15

Precision radial velocity (RV) measurements in the near-infrared are a powerful tool to detect and characterize exoplanets around low-mass stars or young stars with higher magnetic…

astro-ph.EP2020★ 29 cited

Zodiacal Exoplanets in Time. XI. The Orbit and Radiation Environment of the Young M Dwarf-Hosted Planet K2-25b

E. Gaidos, T. Hirano, D. J. Wilson +20

M dwarf stars are high-priority targets for searches for Earth-size and potentially Earth-like planets, but their planetary systems may form and evolve in very different circumstel…

astro-ph.EP2020★ 75 cited

Limits on the Spin-Orbit Angle and Atmospheric Escape for the 22 Myr-old Planet AU Mic b

Teruyuki Hirano, Vigneshwaran Krishnamurthy, Eric Gaidos +19

We obtained spectra of the pre-main sequence star AU Microscopii during a transit of its Neptune-sized planet to investigate its orbit and atmosphere. We used the high-dispersion n…

astro-ph.EP2020★ 42 cited

Zodiacal Exoplanets in Time. X. The Orbit and Atmosphere of the Young "Neptune Desert"-Dwelling Planet K2-100b

E. Gaidos, T. Hirano, A. W. Mann +17

We obtained high-resolution infrared spectroscopy and short-cadence photometry of the 600-800 Myr Praesepe star K2-100 during transits of its 1.67-day planet. This Neptune-size obj…

astro-ph.EP2020★ 51 cited

Evidence for Spin-orbit Alignment in the TRAPPIST-1 System

Teruyuki Hirano, Eric Gaidos, Joshua N. Winn +21

In an effort to measure the Rossiter-McLaughlin effect for the TRAPPIST-1 system, we performed high-resolution spectroscopy during transits of planets e, f, and b. The spectra were…

astro-ph.IM2018★ 8 cited

Fiber mode scrambler for the Subaru infrared Doppler instrument (IRD)

Masato Ishizuka, Takayuki Kotani, Jun Nishikawa +4

We report the results of fiber mode scrambler experiments for the Infra-Red Doppler instrument (IRD) on the Subaru 8.2-m telescope. IRD is a fiber-fed, high precision radial veloci…