Publications (38)
Hydrogen airglow from an escaping ultrahot Jupiter atmosphere
Yapeng Zhang, Chenliang Huang, Aaron Householder +17
Intense high-energy irradiation of close-in gaseous exoplanets drives the rapid escape of their atmospheres, fundamentally shaping planetary demographics. While atmospheric loss is…
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…
TESS asteroseismology of the Kepler red giants
Dennis Stello, Nicholas Saunders, Sam Grunblatt +11
Red giant asteroseismology can provide valuable information for studying the Galaxy as demonstrated by space missions like CoRoT and Kepler. However, previous observations have bee…
TESS Giants Transiting Giants II: The hottest Jupiters orbiting evolved stars
Samuel K. Grunblatt, Nicholas Saunders, Meng Sun +42
Giant planets on short-period orbits are predicted to be inflated and eventually engulfed by their host stars. However, the detailed timescales and stages of these processes are no…
TESS Giants Transiting Giants III: An eccentric warm Jupiter supports a period-eccentricity relation for giant planets transiting evolved stars
Samuel K. Grunblatt, Nicholas Saunders, Ashley Chontos +27
The fate of planets around rapidly evolving stars is not well understood. Previous studies have suggested that relative to the main sequence population, planets transiting evolved…
The Occurrence Rate of Nearby Planetary Companions to Hot Jupiters
Lizhou Sha, Andrew M. Vanderburg, Chelsea X. Huang +33
The paper measures how often hot Jupiters have nearby transiting companion planets using TESS data, finding an occurrence rate of about 8%, which informs theories of hot‑Jupiter fo…
Machine Learning for the Zwicky Transient Facility
Ashish Mahabal, Umaa Rebbapragada, Richard Walters +47
The Zwicky Transient Facility is a large optical survey in multiple filters producing hundreds of thousands of transient alerts per night. We describe here various machine learning…
TESS asteroseismology of Hydri: a subgiant with a born-again dynamo
Travis S. Metcalfe, Jennifer L. van Saders, Daniel Huber +12
The solar-type subgiant Hyi has long been studied as an old analog of the Sun. Although the rotation period has never been measured directly, it was estimated to be near 27 da…
Age-Dating Red Giant Stars Associated with Galactic Disk and Halo Substructures
Samuel K. Grunblatt, Joel C. Zinn, Adrian M. Price-Whelan +12
The vast majority of Milky Way stellar halo stars were likely accreted from a small number (3) of relatively large dwarf galaxy accretion events. However, the timing of t…
Kepler's Discoveries Will Continue: 21 Important Scientific Opportunities with Kepler & K2 Archive Data
Geert Barentsen, Christina Hedges, Nicholas Saunders +4
NASA's Kepler Space Telescope has collected high-precision, high-cadence time series photometry on 781,590 unique postage-stamp targets across 21 different fields of view. These ob…
From Earths to Super-Earths: Five New Small Planets Transiting M Dwarf Stars
Jonathan Gomez Barrientos, Heather A. Knutson, Morgan Saidel +39
Earth-sized planets transiting M dwarf stars present one of the best opportunities with current facilities for studying the atmospheric and bulk compositions of terrestrial worlds.…
Systematics-insensitive Periodogram for finding periods in TESS observations of long-period rotators
Christina Hedges, Ruth Angus, Geert Barentsen +3
NASA's TESS mission \citep{tess} has produced high precision photometry of millions of stars to the community. The majority of TESS observations have a duration of 27 days…
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…
Four Small Planets Buried in K2 Systems: What Can We Learn for TESS?
Christina Hedges, Nicholas Saunders, Geert Barentsen +5
The Kepler, K2, and Transiting Exoplanet Survey Satellite (TESS) missions have provided a wealth of confirmed exoplanets, benefiting from a huge effort from the planet-hunting and…
A catalog of 29 open clusters and associations observed by the Kepler and K2 Missions
Ann Marie Cody, Geert Barentsen, Christina Hedges +5
Over the past nine years, the Kepler and K2 Missions have carried out high precision photometric monitoring of more than half a million stars. Among these targets are 29 clusters a…
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…
A Test of Substellar Evolutionary Models with High-Precision Ages from Asteroseismology and Gyrochronology for the Benchmark System HR 7672AB
Yaguang Li, Michael C. Liu, Trent J. Dupuy +35
We present high-precision measurements for HR~7672AB, composed of a Sun-like (G0V) star and an L~dwarf companion. Three nights of precise (70 cm/s) radial velocity (RV) asteroseism…
Additional Doppler Monitoring Corroborates HAT-P-11 c as a Planet
Samuel W. Yee, Erik A. Petigura, Howard Isaacson +15
In 2010, Bakos and collaborators discovered a Neptune-sized planet transiting the K-dwarf HAT-P-11 every five days. Later in 2018, Yee and collaborators reported an additional Jovi…
The Possible Tidal Demise of Kepler's First Planetary System
Shreyas Vissapragada, Ashley Chontos, Michael Greklek-McKeon +6
We present evidence of tidally-driven inspiral in the Kepler-1658 (KOI-4) system, which consists of a giant planet (1.1, 5.9) orbiting an evolved host s…
Giants Transiting Giants I: A Non-inflated Hot Jupiter Orbiting a Massive Subgiant
Nicholas Saunders, Samuel K. Grunblatt, Daniel Huber +27
While the population of confirmed exoplanets continues to grow, the sample of confirmed transiting planets around evolved stars is still limited. We present the discovery and confi…
Stellar Cruise Control: Weakened Magnetic Braking Leads to Sustained Rapid Rotation of Old Stars
Nicholas Saunders, Jennifer L. van Saders, Alexander J. Lyttle +8
Despite a growing sample of precisely measured stellar rotation periods and ages, the strength of magnetic braking and the degree of departure from standard (Skumanich-like) spindo…
The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
The Astropy Collaboration, Adrian M. Price-Whelan, Pey Lian Lim +133
The Astropy Project supports and fosters the development of open-source and openly-developed Python packages that provide commonly needed functionality to the astronomical communit…
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…
A Testbed for Tidal Migration: the 3D Architecture of an Eccentric Hot Jupiter HD 118203 b Accompanied by a Possibly Aligned Outer Giant Planet
Jingwen Zhang, Daniel Huber, Lauren M. Weiss +31
Characterizing outer companions to hot Jupiters plays a crucial role in deciphering their origins. We present the discovery of a long-period giant planet, HD 118203 c ($m_{c}=11.79…
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…
An unlikely survivor: a low-density hot Neptune orbiting a red giant star
Samuel Grunblatt, Nicholas Saunders, Daniel Huber +14
Hot Neptunes, gaseous planets smaller than Saturn ( 3-8 R) with orbital periods less than 10 days, are rare. Models predict this is due to high-energy stellar irradi…
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…
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…
The Pointing Limits of Transiting Exoplanet Light Curve Characterization with Pixel Level De-correlation
Nicholas Saunders, Rodrigo Luger, Rory Barnes
We present scope (Simulated CCD Observations for Photometric Experimentation), a Python package to create a forward model of telescope detectors and simulate stellar targets with m…
Extreme winds on the emerging dayside of an ultrahot Jupiter
Yapeng Zhang, Joost P. Wardenier, Aaron Householder +16
High-resolution spectroscopy provides a unique opportunity to directly probe atmospheric dynamics by resolving Doppler shifts of planetary signal as a function of orbital phases. U…
The TESS-Keck Survey XXI: 13 New Planets and Homogeneous Properties for 21 Subgiant Systems
Ashley Chontos, Daniel Huber, Samuel K. Grunblatt +67
We present a dedicated transit and radial velocity survey of planets orbiting subgiant stars observed by the TESS Mission. Using nights on Keck/HIRES, we confirm and cha…
K-dwarf Radius Inflation and a 10-Gyr Spin-down Clock Unveiled through Asteroseismology of HD 219134 from the Keck Planet Finder
Yaguang Li, Daniel Huber, J. M. Joel Ong +26
We present the first asteroseismic analysis of the K3\,V planet host HD~219134, based on four consecutive nights of radial velocities collected with the Keck Planet Finder. We appl…
TESS Giants Transiting Giants. VII. A Hot Saturn Orbiting an Oscillating Red Giant Star
Nicholas Saunders, Samuel K. Grunblatt, Daniel Huber +26
We present the discovery of TOI-7041 b (TIC 201175570 b), a hot Saturn transiting a red giant star with measurable stellar oscillations. We observe solar-like oscillations in TOI-7…
An update to the EVEREST K2 pipeline: Short cadence, saturated stars, and Kepler-like photometry down to Kp = 15
Rodrigo Luger, Ethan Kruse, Daniel Foreman-Mackey +2
We present an update to the EVEREST K2 pipeline that addresses various limitations in the previous version and improves the photometric precision of the de-trended light curves. We…
The far side of the Galactic bar/bulge revealed through semi-regular variables
Daniel R. Hey, Daniel Huber, Benjamin J. Shappee +8
The Galactic bulge and bar are critical to our understanding of the Milky Way. However, due to the lack of reliable stellar distances, the structure and kinematics of the bulge/bar…
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…
eleanor: An open-source tool for extracting light curves from the TESS Full-Frame Images
Adina D. Feinstein, Benjamin T. Montet, Daniel Foreman-Mackey +8
During its two year prime mission the Transiting Exoplanet Survey Satellite (TESS) will perform a time-series photometric survey covering over 80% of the sky. This survey comprises…
Discovery of a Jupiter Analog Misaligned to the Inner Planetary System in HD 73344
Jingwen Zhang, Lauren M. Weiss, Daniel Huber +6
We present the discovery of a Jupiter-like planet, HD 73344 d (, AU, ) based on…