75 citations · 1.3k across the 58 of their papers we have counts for
48 papers · 1 filter
A Search for helium in the atmospheres of three sub-Neptunes and a super-Earth around M-dwarfs
Kiyoe Kawauchi, Norio Narita, Yuichi Ito +26
Thousands of sub-Neptunes have been discovered mainly through space-based surveys such as Kepler and TESS. Their bulk compositions and internal structures are thought to reflect th…
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…
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…
The CARMENES search for exoplanets around M dwarfs. Revisiting the GJ 317, GJ 463, and GJ 3512 systems and two newly discovered planets orbiting GJ 9773 and GJ 508.2
J. C. Morales, I. Ribas, S. Reffert +33
Surveys for exoplanets indicate that the occurrence rate of gas giant planets orbiting late-type stars in orbits with periods shorter than 1000 days is lower than in the case of Su…
Atmospheric retrieval of Subaru/IRD high-resolution spectrum of the archetype T-type brown dwarf Gl 229 B
Yui Kawashima, Hajime Kawahara, Yui Kasagi +14
Brown dwarfs provide a unique opportunity to study atmospheres and their physical and chemical processes with high precision, especially in temperature ranges relevant to exoplanet…
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…
Two long-period giant planets around two giant stars: HD 112570 and HD 154391
Guang-Yao Xiao, Huan-Yu Teng, Jianzhao Zhou +24
We present the discoveries of two giant planets orbiting the red giant branch (RGB) star HD 112570 and the red clump (RC) star HD 154391, based on the radial velocity (RV) measurem…
Planetary companions orbiting the M dwarfs GJ 724 and GJ 3988. A CARMENES and IRD collaboration
P. Gorrini, J. Kemmer, S. Dreizler +36
We report the discovery of two exoplanets around the M dwarfs GJ 724 and GJ 3988 using the radial velocity (RV) method. We obtained a total of 153 3.5 m Calar Alto/CARMENES spectra…
Revisiting Planetary Systems in Okayama Planet Search Program: A new long-period planet, RV astrometry joint analysis, and multiplicity-metallicity trend around evolved stars
Huan-Yu Teng, Bun'ei Sato, Masayuki Kuzuhara +15
In this study, we revisit 32 planetary systems around evolved stars observed within the framework of the Okayama Planet Search Program and its collaborative framework of the EAPS-N…
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…
An Earth-sized Planet around an M5 Dwarf Star at 22 pc
Teruyuki Hirano, Fei Dai, John H. Livingston +46
We report on the discovery of an Earth-sized transiting planet () in a day orbit around K2-415 (EPIC 211414619), an M5V star at 22 pc. The pla…
A Close-in Planet Orbiting Giant Star HD 167768
Huan-Yu Teng, Bun'ei Sato, Masanobu Kunitomo +12
We report the detection of a giant planet orbiting a G-type giant star HD 167768 from radial velocity measurements using HIgh Dispersion Echelle Spectrograph (HIDES) at Okayama Ast…
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 Trio of Giant Planets Orbiting Evolved Star HD 184010
Huan-Yu Teng, Bun'ei Sato, Takuya Takarada +11
We report the discovery of a triple-giant-planet system around an evolved star HD 184010 (HR 7421, HIP 96016). This discovery is based on observations from Okayama Planet Search Pr…
Two temperate super-Earths transiting a nearby late-type M dwarf
L. Delrez, C. A. Murray, F. J. Pozuelos +82
In the age of JWST, temperate terrestrial exoplanets transiting nearby late-type M dwarfs provide unique opportunities for characterising their atmospheres, as well as searching fo…
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…
Regular Radial Velocity Variations in Nine G- and K-type Giant Stars: Eight Planets and One Planet Candidate
Huan-Yu Teng, Bun'ei Sato, Takuya Takarada +9
We report the detection of radial velocity variations in nine evolved G- and K-type giant stars. The observations were conducted at Okayama Astrophysical Observatory. Planets or pl…
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…