75 citations · 516 across the 23 of their papers we have counts for
24 papers
Near-infrared spectra of chemically peculiar stars and applications to kilonova spectra
Nanae Domoto, Masaomi Tanaka, Wako Aoki +11
Kilonova spectra provide information on rapid neutron-capture nucleosynthesis in neutron star mergers. However, it remains challenging to identify individual elements in kilonova s…
The mass of TOI-1883 b: A low density super-Neptune in the ridge regime transiting an early-M dwarf
Izuru Fukuda, Norio Narita, Akihiko Fukui +36
Recent large-scale transit surveys conducted by space telescopes such as Kepler and TESS have revealed a vast number of exoplanets, uncovering the diversity of their population. On…
Direct Imaging Explorations for Companions from the Subaru/IRD Strategic Program II; Discovery of a Brown-dwarf Companion around a Nearby mid-M~dwarf LSPM~J1446+4633
Taichi Uyama, Masayuki Kuzuhara, Charles Beichman +35
We report the discovery of a new directly-imaged brown dwarf companion with Keck/NIRC2+pyWFS around a nearby mid-type M~dwarf LSPM~J1446+4633 (hereafter J1446). The -band contr…
The mass of TOI-654 b: A short-period sub-Neptune transiting a mid-M dwarf
Kai Ikuta, Norio Narita, Takuya Takarada +40
Sub-Neptunes are small planets between the size of the Earth and Neptune. The orbital and bulk properties of transiting sub-Neptunes can provide clues for their formation and evolu…
Gliese 12 b: A temperate Earth-sized planet at 12 pc ideal for atmospheric transmission spectroscopy
M. Kuzuhara, A. Fukui, J. H. Livingston +103
Recent discoveries of Earth-sized planets transiting nearby M dwarfs have made it possible to characterize the atmospheres of terrestrial planets via follow-up spectroscopic observ…
The Discovery and Follow-up of Four Transiting Short-period Sub-Neptunes Orbiting M dwarfs
Y. Hori, A. Fukui, T. Hirano +100
Sub-Neptunes with are intermediate in size between rocky planets and Neptune-sized planets. The orbital properties and bulk compositions of transiting sub-Neptunes pr…
Transit Spectroscopy of K2-33b with Subaru/IRD: Spin-Orbit Alignment and Tentative Atmospheric Helium
Teruyuki Hirano, Eric Gaidos, Hiroki Harakawa +13
Exoplanets in their infancy are ideal targets to probe the formation and evolution history of planetary systems, including the planet migration and atmospheric evolution and dissip…
A spectroscopic thermometer: individual vibrational band spectroscopy with the example of OH in the atmosphere of WASP-33b
Sam O. M. Wright, Stevanus K. Nugroho, Matteo Brogi +26
Individual vibrational band spectroscopy presents an opportunity to examine exoplanet atmospheres in detail by distinguishing where the vibrational state populations of molecules d…
The mass determination of TOI-519 b: a close-in giant planet transiting a metal-rich mid-M dwarf
Taiki Kagetani, Norio Narita, Tadahiro Kimura +33
We report the mass determination of TOI-519 b, a transiting substellar object around a mid-M dwarf. We carried out radial velocity measurements using Subaru / InfraRed Doppler (IRD…
Absence of extended atmospheres in low-mass star radius-gap planets GJ 9827 b, GJ 9827 d and TOI-1235 b
Vigneshwaran Krishnamurthy, Teruyuki Hirano, Eric Gaidos +20
\textit{Kepler} showed a paucity of planets with radii of 1.5 - 2 around solar mass stars but this radius-gap has not been well studied for low-mass star plane…
Direct Imaging Explorations for Companions around Mid-Late M Stars from the Subaru/IRD Strategic Program
Taichi Uyama, Charles Beichman, Masayuki Kuzuhara +32
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…
Planet(esimal)s Around Stars with TESS (PAST) III: A Search for Triplet He I in the Atmospheres of Two 200 Myr-old Planets
Eric Gaidos, Teruyuki Hirano, Rena A. Lee +13
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 planets on 0.55- an…
A Super-Earth Orbiting Near the Inner Edge of the Habitable Zone around the M4.5-dwarf Ross 508
Hiroki Harakawa, Takuya Takarada, Yui Kasagi +46
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 (). Using precision RVs f…
TOI-1696: a nearby M4 dwarf with a planet in the Neptunian desert
Mayuko Mori, John H. Livingston, Jerome de Leon +59
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 and an orbita…
Validation and atmospheric exploration of the sub-Neptune TOI-2136b around a nearby M3 dwarf
K. Kawauchi, F. Murgas, E. Palle +51
The NASA space telescope is currently in the extended mission of its all-sky search for new transiting planets. Of the thousands of candidates that TESS is expected to deliv…
Silicon and Strontium abundances of very metal-poor stars determined from near-infrared spectra
Wako Aoki, Timothy C. Beers, Satoshi Honda +19
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…
Zodiacal Exoplanets in Time (ZEIT) XIII: Planet Orbits and Atmospheres in the V1298 Tau System, a Keystone in Studies of Early Planetary Evolution
E. Gaidos, T. Hirano, C. Beichman +16
Studies of planetary systems of stars in star-forming regions and young clusters open a window on the formative stages of planetary evolution. We obtained high-cadence high-resolut…
Zodiacal Exoplanets in Time (ZEIT) XII: A Directly-Imaged Planetary-Mass Companion to a Young Taurus M Dwarf Star
E. Gaidos, T. Hirano, A. L. Kraus +21
We report the discovery of a resolved (0".9) substellar companion to a member of the 1-5 Myr Taurus star-forming region. The host star (2M0437) is a single mid-M type ($T_{eff}\app…
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…
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…
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…
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…
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…
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…