activity
20172026
most citedAn extreme magneto-ionic environment associated with the fast radio burst source FRB 121102

510 citations · 1.5k across the 41 of their papers we have counts for

collaborators

43 papers

astro-ph.EP2026

"Mega-Earths" are likely an artifact of stellar activity

Casey L. Brinkman, Nicolas Cowan

Empirical relations and planet formation simulations suggest an upper mass limit for rocky planets of 10M, as cores above this will almost certainly undergo runawa…

astro-ph.EP2026

Radial velocity detection of the TRAPPIST-1 planetary system with SPIRou and NIRPS

Alexandrine L'Heureux, René Doyon, Charles Cadieux +57

The TRAPPIST-1 system is well-known for its seven transiting Earth-sized exoplanets. It has been extensively studied and characterized, notably with transit timing variations (TTVs…

astro-ph.EP2026

Revisiting the Exo-Mercury Candidate GJ 367 b with ESPRESSO and a Self-Consistent Tidal Distortion Model

Rena A. Lee, Fei Dai, Ellen M. Price +18

We report revised mass and radius measurements for GJ 367 b, an ultra-short-period (7.7 hr) sub-Earth in a multi-planet system orbiting a nearby (~9 pc) M dwarf host. Previous mass…

astro-ph.EP2025★ 1 cited

A Link Between Rocky Planet Density and Host Star Chemistry

Aida Behmard, Casey L. Brinkman, Soichiro Hattori +2

Planets and their host stars form from the same cloud of gas and dust, so we assume that their chemical compositions are linked. However, a clear correlation between rocky planet i…

astro-ph.EP2025

TOI-6324b: An Earth-Mass Ultra-Short-Period Planet Transiting a Nearby M Dwarf

Rena A. Lee, Fei Dai, Andrew W. Howard +71

We report the confirmation of TOI-6324 b, an Earth-sized (1.059 0.041 R) ultra-short-period (USP) planet orbiting a nearby (20 pc) M dwarf. Using the newly com…

astro-ph.EP2025

Planet Masses, Radii, and Orbits from NASA's K2 Mission

Andrew W. Howard, Evan Sinukoff, Sarah Blunt +50

We report the masses, sizes, and orbital properties of 86 planets orbiting 55 stars observed by NASA's K2 Mission with follow-up Doppler measurements by the HIRES spectrometer at t…

astro-ph.EP2024★ 1 cited

The Compositions of Rocky Planets in Close-in Orbits Tend to be Earth-Like

Casey L. Brinkman, Lauren M. Weiss, Daniel Huber +54

Hundreds of exoplanets between 1-1.8 times the size of the Earth have been discovered on close in orbits. However, these planets show such a diversity in densities that some appear…

astro-ph.EP2024

Revisiting the Relationship Between Rocky Exoplanet and Stellar Compositions: Reduced Evidence for a Super-Mercury Population

Casey L. Brinkman, Alex S. Polanski, Daniel Huber +3

Planets and the stars they orbit are born from the same cloud of gas and dust, and the primordial compositions of rocky exoplanets have been assumed to have iron and refractory abu…

astro-ph.EP2024★ 13 cited

TESS Giants Transiting Giants. VI. Newly Discovered Hot Jupiters Provide Evidence for Efficient Obliquity Damping after the Main Sequence

Nicholas Saunders, Samuel K. Grunblatt, Ashley Chontos +53

The degree of alignment between a star's spin axis and the orbital plane of its planets (the stellar obliquity) is related to interesting and poorly understood processes that occur…

astro-ph.EP2024

An Earth-sized Planet on the Verge of Tidal Disruption

Fei Dai, Andrew W. Howard, Samuel Halverson +95

TOI-6255~b (GJ 4256) is an Earth-sized planet (1.079 ) with an orbital period of only 5.7 hours. With the newly commissioned Keck Planet Finder (KPF) and CARMEN…

astro-ph.SR2024

The California Legacy Survey V. Chromospheric Activity Cycles in Main Sequence Stars

Howard Isaacson, Andrew W. Howard, Benjamin Fulton +31

We present optical spectroscopy of 710 solar neighborhood stars collected over twenty years to catalog chromospheric activity and search for stellar activity cycles. The California…

astro-ph.EP2024★ 53 cited

The TESS-Keck Survey XX: 15 New TESS Planets and a Uniform RV Analysis of all Survey Targets

Alex S. Polanski, Jack Lubin, Corey beard +69

The Transiting Exoplanet Survey Satellite (TESS) has discovered hundreds of new worlds, with TESS planet candidates now outnumbering the total number of confirmed planets from $\te…

astro-ph.EP2024

The TESS-Keck Survey. XXII. A sub-Neptune Orbiting TOI-1437

Daria Pidhorodetska, Emily A. Gilbert, Stephen R. Kane +40

Exoplanet discoveries have revealed a dramatic diversity of planet sizes across a vast array of orbital architectures. Sub-Neptunes are of particular interest; due to their absence…

astro-ph.EP2024★ 6 cited

Planet Hunters TESS V: a planetary system around a binary star, including a mini-Neptune in the habitable zone

Nora L. Eisner, Samuel K. Grunblatt, Oscar Barragán +61

We report on the discovery and validation of a transiting long-period mini-Neptune orbiting a bright (V = 9.0 mag) G dwarf (TOI 4633; R = 1.05 RSun, M = 1.10 MSun). The planet was…

astro-ph.EP2024

A Tale of Two Peas-In-A-Pod: The Kepler-323 and Kepler-104 Systems

C. Alexander Thomas, Lauren M. Weiss, Howard Isaacson +10

In order to understand the relationship between planet multiplicity, mass, and composition, we present newly measured masses of five planets in two planetary systems: Kepler-323 an…

astro-ph.EP2024

The TESS-Keck Survey. XII. A Dense 1.8 R Ultra-Short-Period Planet Possibly Clinging to a High-Mean-Molecular-Weight Atmosphere After the First Gyr

Ryan A. Rubenzahl, Fei Dai, Andrew W. Howard +39

The extreme environments of ultra-short-period planets (USPs) make excellent laboratories to study how exoplanets obtain, lose, retain, and/or regain gaseous atmospheres. We presen…

astro-ph.EP2024

The TESS-Keck Survey. XVIII. A sub-Neptune and spurious long-period signal in the TOI-1751 system

Anmol Desai, Emma V. Turtelboom, Caleb K. Harada +37

We present and confirm TOI-1751 b, a transiting sub-Neptune orbiting a slightly evolved, solar-type, metal-poor star ( K, , V = 9.3 ma…

astro-ph.EP2024

Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey. IV. Long-term Doppler Spectroscopy for 11 Stars Thought to Host Cool Giant Exoplanets

Paul A. Dalba, Stephen R. Kane, Howard Isaacson +29

Discovering and characterizing exoplanets at the outer edge of the transit method's sensitivity has proven challenging owing to geometric biases and the practical difficulties asso…

astro-ph.EP2023

The TESS-Keck Survey XVII: Precise Mass Measurements in a Young, High Multiplicity Transiting Planet System using Radial Velocities and Transit Timing Variations

Corey Beard, Paul Robertson, Fei Dai +41

We present a radial velocity (RV) analysis of TOI-1136, a bright TESS system with six confirmed transiting planets, and a seventh single-transiting planet candidate. All planets in…

astro-ph.EP2023★ 11 cited

TESS Giants Transiting Giants V -- Two hot Jupiters orbiting red-giant hosts

Filipe Pereira, Samuel K. Grunblatt, Angelica Psaridi +24

In this work we present the discovery and confirmation of two hot Jupiters orbiting red-giant stars, TOI-4377 b and TOI-4551 b, observed by TESS in the southern ecliptic hemisphere…

astro-ph.EP2023★ 15 cited

TOI-1801 b: A temperate mini-Neptune around a young M0.5 dwarf

M. Mallorquín, E. Goffo, E. Pallé +79

We report the discovery, mass, and radius determination of TOI-1801 b, a temperate mini-Neptune around a young M dwarf. TOI-1801 b was observed in TESS sectors 22 and 49, and the a…

astro-ph.EP2023

Investigating the Atmospheric Mass Loss of the Kepler-105 Planets Straddling the Radius Gap

Aaron Householder, Lauren M. Weiss, James E. Owen +21

An intriguing pattern among exoplanets is the lack of detected planets between approximately R and R. One proposed explanation for this "radius gap" i…

astro-ph.EP2023

The TESS-Keck Survey. XVI. Mass Measurements for 12 Planets in Eight Systems

Joseph M. Akana Murphy, Natalie M. Batalha, Nicholas Scarsdale +44

With JWST's successful deployment and unexpectedly high fuel reserves, measuring the masses of sub-Neptunes transiting bright, nearby stars will soon become the bottleneck for char…

astro-ph.SR2023★ 23 cited

A close-in giant planet escapes engulfment by its star

Marc Hon, Daniel Huber, Nicholas Z. Rui +39

When main-sequence stars expand into red giants, they are expected to engulf close-in planets. Until now, the absence of planets with short orbital periods around post-expansion, c…