Corey Beard

The TESS-Keck Survey. XI. Mass Measurements for Four Transiting sub-Neptunes orbiting K dwarf TOI-1246

Emma V. Turtelboom, Lauren M. Weiss, Courtney D. Dressing +78

Multi-planet systems are valuable arenas for investigating exoplanet architectures and comparing planetary siblings. TOI-1246 is one such system, with a moderately bright K dwarf (…

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…

TESS-Keck Survey XIV: Two giant exoplanets from the Distant Giants Survey

Judah E. Van Zandt, Erik A. Petigura, Mason MacDougall +42

We present the Distant Giants Survey, a three-year radial velocity (RV) campaign to measure P(DG|CS), the conditional occurrence of distant giant planets (DG; M_p ~ 0.3 - 13 M_J, P…

TOI-3714 b and TOI-3629 b: Two gas giants transiting M dwarfs confirmed with HPF and NEID

Caleb I. CaÃ±as, Shubham Kanodia, Chad F. Bender +36

We confirm the planetary nature of two gas giants discovered by TESS to transit M dwarfs. TOI-3714 ( $V = 15.24, J = 11.74$ ) is an M2 dwarf hosting a hot Jupiter ($M_p=0.70 \pm 0.03~\ma…

Utilizing Photometry from Multiple Sources to Mitigate Stellar Variability in Precise Radial Velocities: A Case Study of Kepler-21

Corey Beard, Paul Robertson, Mark R. Giovinazzi +26

We present a new analysis of Kepler-21, the brightest (V = 8.5) Kepler system with a known transiting exoplanet, Kepler-21 b. Kepler-21 b is a radius valley planet ($R = 1.6\pm 0.2…

TOI-1235 b: a keystone super-Earth for testing radius valley emergence models around early M dwarfs

Ryan Cloutier, Joseph E. Rodriguez, Jonathan Irwin +85

Small planets on close-in orbits tend to exhibit envelope mass fractions of either effectively zero or up to a few percent depending on their size and orbital period. Models of the…

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…

TKS V. Twin sub-Neptunes Transiting the Nearby G Star HD 63935

Nicholas Scarsdale, Joseph M. Akana Murphy, Natalie M. Batalha +56

We present the discovery of two nearly identically-sized sub-Neptune transiting planets orbiting HD 63935, a bright ( $V = 8.6$ mag), sun-like ( $T_{e f f} = 5560 K$ ) star at 49 pc. TESS id…

A warm Jupiter transiting an M dwarf: A TESS single transit event confirmed with the Habitable-zone Planet Finder

Caleb I. CaÃ±as, Gudmundur Stefansson, Shubham Kanodia +30

We confirm the planetary nature of a warm Jupiter transiting the early M dwarf TOI-1899, using a combination of available TESS photometry; high-precision, near-infrared spectroscop…

The unusual M-dwarf Warm Jupiter TOI-1899~b: Refinement of orbital and planetary parameters

Andrea S. J. Lin, Jessica E. Libby-Roberts, Jaime A. Alvarado-Montes +31

TOI-1899 b is a rare exoplanet, a temperate Warm Jupiter orbiting an M-dwarf, first discovered by CaÃ±as et al. (2020) from a TESS single-transit event. Using new radial velocities…

Stellar Activity Manifesting at a One Year Alias Explains Barnard b as a False Positive

Jack Lubin, Paul Robertson, Gudmundur Stefansson +17

Barnard's star is among the most studied stars given its proximity to the Sun. It is often considered $t h e$ Radial Velocity (RV) standard for fully convective stars due to its RV s…

The HD 191939 Exoplanet System is Well-Aligned and Flat

Jack Lubin, Erik A. Petigura, Judah Van Zandt +25

We report the sky-projected spin-orbit angle $I^»$ for HD 191939 b, the innermost planet in a 6 planet system, using Keck/KPF to detect the Rossiter-McLaughlin (RM) effect. Planet b…

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…

$I ¨ $ Earth: a 3.14-day Earth-sized Planet from $K2$ 's Kitchen Served Warm by the SPECULOOS Team

Prajwal Niraula, Julien de Wit, Benjamin V. Rackham +25

We report on the discovery of a transiting Earth-sized (0.95 $R_{\oplus}$ ) planet around an M3.5 dwarf star at 57pc, K2-315b. The planet has a period of $\sim$ 3.14 days, i.e. ${\s…

The TESS-Keck Survey IV: A Retrograde, Polar Orbit for the Ultra-Low-Density, Hot Super-Neptune WASP-107b

Ryan A. Rubenzahl, Fei Dai, Andrew W. Howard +21

We measured the Rossiter-McLaughlin effect of WASP-107b during a single transit with Keck/HIRES. We found the sky-projected inclination of WASP-107b's orbit, relative to its host s…

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…

The TESS-Keck Survey. XIX. A Warm Transiting Sub-Saturn Mass Planet and a non-Transiting Saturn Mass Planet Orbiting a Solar Analog

Michelle L. Hill, Stephen R. Kane, Paul A. Dalba +45

The Transiting Exoplanet Survey Satellite (TESS) continues to dramatically increase the number of known transiting exoplanets, and is optimal for monitoring bright stars amenable t…

The TESS-Keck Survey. VI. Two Eccentric sub-Neptunes Orbiting HIP-97166

Mason G. MacDougall, Erik A. Petigura, Isabel Angelo +45

We report the discovery of HIP-97166b (TOI-1255b), a transiting sub-Neptune on a 10.3-day orbit around a K0 dwarf 68 pc from Earth. This planet was identified in a systematic searc…

TOI-532b: The Habitable-zone Planet Finder confirms a Large Super Neptune in the Neptune Desert orbiting a metal-rich M dwarf host

Shubham Kanodia, Gudmundur Stefansson, Caleb I. Canas +30

We confirm the planetary nature of TOI-532b, using a combination of precise near-infrared radial velocities with the Habitable-zone Planet Finder, TESS light curves, ground based p…

The multi-planet system TOI-421 -- A warm Neptune and a super puffy mini-Neptune transiting a G9 V star in a visual binary

Ilaria Carleo, Davide Gandolfi, Oscar BarragÃ¡n +110

We report the discovery of a warm Neptune and a hot sub-Neptune transiting TOI-421 (BD-14 1137, TIC 94986319), a bright (V=9.9) G9 dwarf star in a visual binary system observed by…

Jitter Across 15 Years: Leveraging Precise Photometry from Kepler and TESS to Extract Exoplanets from Radial Velocity Time Series

Corey Beard, Paul Robertson, Jack Lubin +24

Stellar activity contamination of radial velocity (RV) data is one of the top challenges plaguing the field of extreme precision RV (EPRV) science. Previous work has shown that pho…

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 $1.5$ R $_{\oplus}$ and $2.0$ R $_{\oplus}$ . One proposed explanation for this "radius gap" i…

The TESS-Keck Survey. XII. A Dense 1.8 R $_{\oplus}$ 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…

Overfitting Affects the Reliability of Radial Velocity Mass Estimates of the V1298 Tau Planets

Sarah Blunt, Adolfo Carvalho, Trevor J. David +23

Mass, radius, and age measurements of young (<100 Myr) planets have the power to shape our understanding of planet formation. However, young stars tend to be extremely variable in…

TOI-3984 A b and TOI-5293 A b: two temperate gas giants transiting mid-M dwarfs in wide binary systems

Caleb I. CaÃ±as, Shubham Kanodia, Jessica Libby-Roberts +30

We confirm the planetary nature of two gas giants discovered by TESS to transit M dwarfs with stellar companions at wide separations. TOI-3984 A ( $J = 11.93$ ) is an M4 dwarf hosting…

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.SR2023

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…

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…

The Kepler Giant Planet Search. I: A Decade of Kepler Planet-host Radial Velocities from W. M. Keck Observatory

Lauren M. Weiss, Howard Isaacson, Andrew W. Howard +17

Despite the importance of Jupiter and Saturn to Earth's formation and habitability, there has not yet been a comprehensive observational study of how giant exoplanets correlate wit…

The TESS-Keck Survey. XV. Precise Properties of 108 TESS Planets and Their Host Stars

Mason G. MacDougall, Erik A. Petigura, Gregory J. Gilbert +38

We present the stellar and planetary properties for 85 TESS Objects of Interest (TOIs) hosting 108 planet candidates which comprise the TESS-Keck Survey (TKS) sample. We combine ph…

The TESS-Keck Survey II: An Ultra-Short Period Rocky Planet and its Siblings Transiting the Galactic Thick-Disk Star TOI-561

Lauren M. Weiss, Fei Dai, Daniel Huber +61

We report the discovery of TOI-561, a multi-planet system in the galactic thick disk that contains a rocky, ultra-short period planet (USP). This bright ( $V = 10.2$ ) star hosts three…

The TESS-Keck Survey I: A Warm Sub-Saturn-mass Planet and a Caution about Stray Light in TESS Cameras

Paul A. Dalba, Arvind F. Gupta, Joseph E. Rodriguez +63

We report the detection of a Saturn-size exoplanet orbiting HD 332231 (TOI 1456) in light curves from the Transiting Exoplanet Survey Satellite (TESS). HD 332231, an F8 dwarf star…

The TESS-Keck Survey XXIV: Outer Giants may be More Prevalent in the Presence of Inner Small Planets

Judah Van Zandt, Erik A. Petigura, Jack Lubin +38

We present the results of the Distant Giants Survey, a three-year radial velocity (RV) campaign to search for wide-separation giant planets orbiting Sun-like stars known to host an…

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…

astro-ph.SR2022

An eccentric Brown Dwarf eclipsing an M dwarf

Caleb I. CaÃ±as, Suvrath Mahadevan, Chad F. Bender +16

We report the discovery of a $M = 67 \pm 2 M_{J}$ brown dwarf transiting the early M dwarf TOI-2119 on an eccentric orbit ( $e = 0.3362 \pm 0.0005$ ) at an orbital period of $7.2008…

TOI-561 b: A Low Density Ultra-Short Period "Rocky" Planet around a Metal-Poor Star

Casey Brinkman, Lauren M. Weiss, Fei Dai +22

TOI-561 is a galactic thick disk star hosting an ultra-short period (0.45 day orbit) planet with a radius of 1.37 R $_{\oplus}$ , making it one of the most metal-poor ([Fe/H] = -0.41…

TOI-3757 b: A low density gas giant orbiting a solar-metallicity M dwarf

Shubham Kanodia, Jessica Libby-Roberts, Caleb I. Canas +32

We present the discovery of a new Jovian-sized planet, TOI-3757 b, the lowest density planet orbiting an M dwarf (M0V). It orbits a solar-metallicity M dwarf discovered using TESS…

TOI-1670 c, a 40-day Orbital Period Warm Jupiter in a Compact System, is Well-aligned

Jack Lubin, Xian-Yu Wang, Malena Rice +21

We report the measurement of the sky-projected obliquity angle $I^»$ of the Warm Jovian exoplanet TOI-1670 c via the Rossiter-McLaughlin effect as part of the Stellar Obliquities in…

astro-ph.SR2022

Rotational modulation of spectroscopic Zeeman signatures in low-mass stars

Ryan C. Terrien, Allison Keen, Katy Oda +24

Accurate tracers of the stellar magnetic field and rotation are cornerstones for the study of M dwarfs and for reliable detection and characterization of their exoplanetary compani…

Discovery of a Nearby Habitable Zone Super-Earth Candidate Amenable to Direct Imaging

Corey Beard, Paul Robertson, Jack Lubin +31

We present the discovery of GJ 251 c, a candidate super-Earth orbiting in the Habitable Zone (HZ) of its M dwarf host star. Using high-precision Habitable-zone Planet Finder (HPF)…

A Larger Sample Confirms Small Planets Around Hot Stars Are Misaligned

Emma M. Louden, Songhu Wang, Joshua N. Winn +7

The distribution of stellar obliquities provides critical insight into the formation and evolution pathways of exoplanets. In the past decade, it was found that hot stars hosting h…

GJ 3929: High Precision Photometric and Doppler Characterization of an Exo-Venus and its Hot, Mini-Neptune-mass Companion

Corey Beard, Paul Robertson, Shubham Kanodia +31

We detail the follow up and characterization of a transiting exo-Venus identified by TESS, GJ 3929b, (TOI-2013b) and its non-transiting companion planet, GJ 3929c (TOI-2013c). GJ 3…

The Aligned Orbit of WASP-148b, the Only Known Hot Jupiter with a Nearby Warm Jupiter Companion, from NEID and HIRES

Xian-Yu Wang, Malena Rice, Songhu Wang +39

We present spectroscopic measurements of the Rossiter-McLaughlin effect for WASP-148b, the only known hot Jupiter with a nearby warm-Jupiter companion, from the WIYN/NEID and Keck/…

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…

The TESS-Keck Survey: Science Goals and Target Selection

Ashley Chontos, Joseph M. Akana Murphy, Mason G. MacDougall +28

Space-based transit missions such as Kepler and TESS have demonstrated that planets are ubiquitous. However, the success of these missions heavily depends on ground-based radial ve…

The TESS-Keck Survey. VIII. Confirmation of a Transiting Giant Planet on an Eccentric 261 day Orbit with the Automated Planet Finder Telescope

Paul A. Dalba, Stephen R. Kane, Diana Dragomir +72

We report the discovery of TOI-2180 b, a 2.8 $M_{J}$ giant planet orbiting a slightly evolved G5 host star. This planet transited only once in Cycle 2 of the primary Transiting…

TOI-2015b: A Warm Neptune with Transit Timing Variations Orbiting an Active mid M Dwarf

Sinclaire E. Jones, Gudmundur Stefansson, Kento Masuda +29

We report the discovery of a close-in ( $P_{orb} = 3.349 days$ ) warm Neptune with clear transit timing variations (TTVs) orbiting the nearby ($d=47.3\:\mathrm{pc}…

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…

TOI-1136 is a Young, Coplanar, Aligned Planetary System in a Pristine Resonant Chain

Fei Dai, Kento Masuda, Corey Beard +60

Convergent disk migration has long been suspected to be responsible for forming planetary systems with a chain of mean-motion resonances (MMR). Dynamical evolution over time could…

Hundreds of TESS exoplanets might be larger than we thought

Te Han, Paul Robertson, Timothy D. Brandt +5

The radius of a planet is a fundamental parameter that probes its composition and habitability. Precise radius measurements are typically derived from the fraction of starlight blo…

TESS-Keck Survey IX: Masses of Three Sub-Neptunes Orbiting HD 191939 and the Discovery of a Warm Jovian Plus a Distant Sub-Stellar Companion

Jack Lubin, Judah Van Zandt, Rae Holcomb +32

Exoplanet systems with multiple transiting planets are natural laboratories for testing planetary astrophysics. One such system is HD 191939 (TOI-1339), a bright (V=9) and Sun-like…

TKS III: A Stellar Obliquity Measurement of TOI-1726 c

Fei Dai, Arpita Roy, Benjamin Fulton +43

We report the measurement of a spectroscopic transit of TOI-1726 c, one of two planets transiting a G-type star with $V$ = 6.9 in the Ursa Major Moving Group ( $\sim$ 400 Myr). With…

The TESS-Keck Survey. XIII. An Eccentric Hot Neptune with a Similar-Mass Outer Companion around TOI-1272

Mason G. MacDougall, Erik A. Petigura, Tara Fetherolf +58

We report the discovery of an eccentric hot Neptune and a non-transiting outer planet around TOI-1272. We identified the eccentricity of the inner planet, with an orbital period of…

Stellar Obliquities in Long-period Exoplanet Systems (SOLES) I: The Spin-Orbit Alignment of K2-140 b

Malena Rice, Songhu Wang, Andrew W. Howard +8

Obliquity measurements for stars hosting relatively long-period giant planets with weak star-planet tidal interactions may play a key role in distinguishing between formation theor…

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 $\pm 0.065$ $R_{\oplus}$ ) 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 ( $\sim$ 3-8 R $_{\oplus}$ ) 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 $\pm$ 0.041 R $_{\oplus}$ ) ultra-short-period (USP) planet orbiting a nearby ( $\sim$ 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 BarragÃ¡n +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 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…

TKS X: Confirmation of TOI-1444b and a Comparative Analysis of the Ultra-short-period Planets with Hot Neptunes

Fei Dai, Andrew W. Howard, Natalie M. Batalha +48

We report the discovery of TOI-1444b, a 1.4- $R_{\oplus}$ super-Earth on a 0.47-day orbit around a Sun-like star discovered by {\it TESS}. Precise radial velocities from Keck/HIRES co…

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 $\sim$ $16$ nights on Keck/HIRES, we confirm and cha…

A close-in puffy Neptune with hidden friends: The enigma of TOI 620

Michael A. Reefe, Rafael Luque, Eric Gaidos +82

We present the validation of a transiting low-density exoplanet orbiting the M2.5 dwarf TOI 620 discovered by the NASA TESS mission. We utilize photometric data from both TESS and…

TOI 560 : Two Transiting Planets Orbiting a K Dwarf Validated with iSHELL, PFS and HIRES RVs

Mohammed El Mufti, Peter P. Plavchan, Howard Isaacson +92

We validate the presence of a two-planet system orbiting the 0.15--1.4 Gyr K4 dwarf TOI 560 (HD 73583). The system consists of an inner moderately eccentric transiting mini-Neptune…

TOI-1696 and TOI-2136: Constraining the Masses of Two Mini-Neptunes with HPF

Corey Beard, Paul Robertson, Shubham Kanodia +29

We present the validation of two planets orbiting M dwarfs, TOI-1696b and TOI-2136b. Both planets are mini-Neptunes orbiting nearby stars, making them promising prospects for atmos…

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…

A Mini-Neptune Orbiting the Metal-poor K Dwarf BD+29 2654

Fei Dai, Kevin C. Schlaufman, Henrique Reggiani +48

We report the discovery and Doppler mass measurement of a 7.4-day 2.3- $R_{\oplus}$ mini-Neptune around a metal-poor K dwarf BD+29 2654 (TOI-2018). Based on a high-resolution Keck/HIR…

astro-ph.EP2019

A sub-Neptune sized planet transiting the M2.5-dwarf G 9-40: Validation with the Habitable-zone Planet Finder

Gudmundur Stefansson, Caleb CaÃ±as, John Wisniewski +32

We validate the discovery of a 2 Earth radii sub-Neptune-size planet around the nearby high proper motion M2.5-dwarf G 9-40 (EPIC 212048748), using high-precision near-infrared (NI…