activity
20232026
most citedThe Aligned Orbit of the Eccentric Proto Hot Jupiter TOI-3362b

29 citations · 87 across the 15 of their papers we have counts for

collaborators

16 papers

astro-ph.EP2026

The Discovery of K2-232c: Divergent Formation Histories for Hot and Warm Jupiters Based on Outer Companion Eccentricity

Jessica A. Ranshaw, Xian-Yu Wang, Jennifer A. Burt +6

Ever since their discovery, hot Jupiters have been one of the most studied types of exoplanets to exist thanks to their significant size, their proximity to their host star, and th…

astro-ph.EP2026

POSEIDON III: The Aligned Orbit of the Hot Neptune Around the Hot Star WASP-195

Juan I. Espinoza-Retamal, Joshua N. Winn, Rafael Brahm +33

Stellar obliquities provide important clues as to the formation and migration histories of planetary systems, but measurements remain scarce for Neptune-mass planets, especially th…

astro-ph.EP2026

POSEIDON II: The Anti-Aligned Orbit of the Warm Neptune TOI-1710 A b

Juan I. Espinoza-Retamal, Hareesh Bhaskar, Joshua N. Winn +7

We present an observation of the Rossiter-McLaughlin effect for the TOI-1710 system with the NEID spectrograph on the WIYN 3.5 m telescope. The system hosts a warm Neptune ($P\sim2…

astro-ph.EP2026

The Neptunian ridge planet WASP-156 b does not have a polar orbit

M. Lafarga, J. I. Espinoza-Retamal, H. M. Cegla +26

The population of short-period exo-Neptunes is thought to be shaped by an interplay between different dynamical mechanisms, such as orbital migration and tidal effects, and photoev…

astro-ph.EP2026

POSEIDON I: The Dynamical Origins of Transiting Neptunes

Juan I. Espinoza-Retamal, Joshua N. Winn, Rafael Brahm +17

We present the first results from the POSEIDON survey, aimed at constraining the dynamical origins of transiting Neptunes through stellar obliquity measurements. We report Rossiter…

astro-ph.EP2025

A Compact Multi-Planet System of Three Transiting Giant Planets Around TIC118798035

Rafael Brahm, Trifon Trifonov, Andrés Jordán +20

We report the discovery and characterization of three transiting giant planets in the TIC118798035 system. The three planets were identified as transiting candidates from data of t…

astro-ph.EP2025

High five from ASTEP: Three validated planets and two eclipsing binaries in a diverse set of long-period candidates

Erika Rea, Maximilian N. Günther, George Dransfield +44

We present the analysis of five long-period TESS Objects of Interest (TOIs), all orbiting Sun-like stars, with orbital periods exceeding one month. Initially identified by the Tran…

astro-ph.EP2025★ 2 cited

A Cold and Super-Puffy Planet on a Prograde Orbit

Juan I. Espinoza-Retamal, Rafael Brahm, Cristobal Petrovich +36

We report the discovery of TOI-4507 b, a transiting sub-Saturn with a density 0.2 g/cm on a 105-day prograde orbit around a 700 Myr old F star. The transits were detected u…

astro-ph.EP2025

Spectroscopic Characterization of LOFAR Radio-emitting M dwarfs

E. Koo, G. Stefansson, R. D. Kavanagh +20

Recent observations with the LOw Frequency ARray (LOFAR) have revealed 19 nearby M dwarfs showing bright circularly polarised radio emission. One of the possible sources of such em…

astro-ph.EP2025★ 2 cited

An Earth-Sized Planet in a 5.4h Orbit Around a Nearby K dwarf

Kaya Han Taş, Gudmundur Stefansson, Syarief N. M. Fariz +25

We present the discovery and confirmation of the ultra-short period (USP) planet TOI-2431 b orbiting a nearby ( pc) late K star ( = $4109 \pm 28 \, {\rm…

astro-ph.EP2025★ 1 cited

TOI-1259Ab: A Warm Jupiter Orbiting a K-dwarf White-Dwarf Binary is on a Well-aligned Orbit

Hugo Veldhuis, Juan I. Espinoza-Retamal, Gudmundur Stefansson +21

The evolution of one member of a stellar binary into a white dwarf has been proposed as a mechanism that triggers the formation of close-in gas giant planets. The star's asymmetric…

astro-ph.EP2024★ 16 cited

The Spin-Orbit Alignment of 8 Warm Gas Giant Systems

Juan I. Espinoza-Retamal, Andrés Jordán, Rafael Brahm +9

Essential information about the formation and evolution of planetary systems can be found in their architectures -- in particular, in stellar obliquity () -- as they serve as a…

astro-ph.EP2024

Gaia-4b and 5b: Radial Velocity Confirmation of Gaia Astrometric Orbital Solutions Reveal a Massive Planet and a Brown Dwarf Orbiting Low-mass Stars

Gudmundur Stefansson, Suvrath Mahadevan, Joshua Winn +31

Gaia astrometry of nearby stars is precise enough to detect the tiny displacements induced by substellar companions, but radial velocity data are needed for definitive confirmation…

astro-ph.EP2024★ 20 cited

HATS-38 b and WASP-139 b join a growing group of hot Neptunes on polar orbits

Juan I. Espinoza-Retamal, Guðmundur Stefánsson, Cristobal Petrovich +9

We constrain the sky-projected obliquities of two low-density hot Neptune planets, HATS-38 b and WASP-139 b, orbiting nearby G and K stars using Rossiter-McLaughlin (RM) observatio…

astro-ph.EP2023★ 17 cited

Prospects from TESS and Gaia to constrain the flatness of planetary systems

Juan I. Espinoza-Retamal, Wei Zhu, Cristobal Petrovich

The mutual inclination between planets orbiting the same star provides key information to understand the formation and evolution of multi-planet systems. In this work, we investiga…

astro-ph.EP2023★ 29 cited

The Aligned Orbit of the Eccentric Proto Hot Jupiter TOI-3362b

Juan I. Espinoza-Retamal, Rafael Brahm, Cristobal Petrovich +8

High-eccentricity tidal migration predicts the existence of highly eccentric proto-hot Jupiters on the "tidal circularization track," meaning that they might eventually become hot…