399 citations · 8.4k across the 106 of their papers we have counts for
43 papers · 1 filter
Debris Rings from Extrasolar Irregular Satellites
Kevin T. Hayakawa, Bradley M. S. Hansen
Irregular satellites are the minor bodies found orbiting all four Solar System giant planets, with large semi-major axes, eccentricities, and inclinations. Previous studies have de…
Halting Migration in Magnetospherically Sculpted Protoplanetary Disks
Tze Yeung Mathew Yu, Brad Hansen, Yasuhiro Hasegawa
We present a physically motivated model for the manner in which a stellar magnetic field sculpts the inner edge of a protoplanetary disk, and examine the consequence for the migrat…
Consequences of dynamically unstable moons in extrasolar systems
Bradley M. S. Hansen
Moons orbiting rocky exoplanets in compact orbits about other stars experience an accelerated tidal evolution, and can either merge with their parent planet or reach the limit of d…
An Exomoon Survey of 70 Cool Giant Exoplanets and the New Candidate Kepler-1708 b-i
David Kipping, Steve Bryson, Chris Burke +6
Exomoons represent a crucial missing puzzle piece in our efforts to understand extrasolar planetary systems. To address this deficiency, we here describe an exomoon survey of 70 co…
The Stationary Points of the Hierarchical Three Body Problem
Bradley M. S. Hansen, Smadar Naoz
We study the stationary points of the hierarchical three body problem in the planetary limit (m_2, m_3 << m_1) at both the quadrupole and octupole orders. We demonstrate that the e…
Close-in giant-planet formation via in-situ gas accretion and their natal disk properties
Yasuhiro Hasegawa, Tze Yeung Mathew Yu, Bradley M. S. Hansen
The origin of close-in Jovian planets is still elusive. We examine the in-situ gas accretion scenario as a formation mechanism of these planets. We reconstruct natal disk propertie…
Accounting for Multiplicity in Calculating Eta Earth
Jon K. Zink, Bradley M. S. Hansen
Using the updated exoplanet population parameters of our previous study, which includes the planetary radius updates from Gaia DR2 and an inferred multiplicity distribution, we pro…
The Chaotic Nature of TRAPPIST-1 Planetary Spin States
Alec M. Vinson, Daniel Tamayo, Brad M. S. Hansen
The TRAPPIST-1 system has 7 known terrestrial planets arranged compactly in a mean motion resonant chain around an ultra-cool central star, some within the estimated habitable zone…
The Heavy-element Content Trend of Planets: A Tracer of their Formation Sites
Yasuhiro Hasegawa, Bradley M. S. Hansen, Gautam Vasisht
Identification of the main planet formation site is fundamental to understanding how planets form and migrate to the current locations. We consider the heavy-element content trend…
Spitzer transit follow-up of planet candidates from the K2 mission
John H. Livingston, Ian J. M. Crossfield, Michael W. Werner +21
We present precision 4.5 m Spitzer transit photometry of eight planet candidates discovered by the K2 mission: K2-52 b, K2-53 b, EPIC 205084841.01, K2-289 b, K2-174 b, K2-87 b,…
Accounting for Incompleteness due to Transit Multiplicity in Kepler Planet Occurrence Rates
Jon K. Zink, Jessie L. Christiansen, Bradley M. S. Hansen
We investigate the role that planet detection order plays in the Kepler planet detection pipeline. The Kepler pipeline typically detects planets in order of descending signal stren…
A dynamical context for the origin of Phobos and Deimos
Bradley M. S. Hansen
We show that a model in which Mars grows near Earth and Venus but is then scattered out of the terrestrial region yields a natural pathway to explain the low masses of the Martian…
Ejection of material --"Jurads" -- from post main sequence planetary systems
Brad Hansen, Ben Zuckerman
We show that the rate of pollution of white dwarfs by asteroidal material implies a concomitant rate of material ejection that can contribute significantly to the population of int…
Constraining Planetary Migration and Tidal Dissipation with Coeval Hot Jupiters
Christopher E. O'Connor, Bradley M. S. Hansen
We investigate the constraints on the formation of, and tidal dissipation processes in, hot Jupiters (HJs) that can be inferred based on reliable knowledge of the age of a system o…
Three's Company: An additional non-transiting super-Earth in the bright HD 3167 system, and masses for all three planets
Jessie L. Christiansen, Andrew Vanderburg, Jennifer Burt +55
HD 3167 is a bright (V = 8.9), nearby K0 star observed by the NASA K2 mission (EPIC 220383386), hosting two small, short-period transiting planets. Here we present the results of a…
K2-66b and K2-106b: Two extremely hot sub-Neptune-size planets with high densities
Evan Sinukoff, Andrew W. Howard, Erik A. Petigura +20
We report precise mass and density measurements of two extremely hot sub-Neptune-size planets from the K2 mission using radial velocities, K2 photometry, and adaptive optics imagin…
On the Spin States of Habitable Zone Exoplanets Around M Dwarfs: The Effect of a Near-Resonant Companion
Alec M. Vinson, Brad M. S. Hansen
One longstanding problem for the potential habitability of planets within M dwarf systems is their likelihood to be tidally locked in a synchronously rotating spin state. This prob…
Mass Constraints of the WASP-47 Planetary System from Radial Velocities
Evan Sinukoff, Andrew W. Howard, Erik A. Petigura +19
We report precise radial velocity (RV) measurements of WASP-47, a G star that hosts three transiting planets in close proximity (a hot Jupiter, a super-Earth and a Neptune-sized pl…
Perturbation of Compact Planetary Systems by Distant Giant Planets
Bradley M. S. Hansen
We examine the effect of secular perturbations by giant planets on systems of multiple, lower mass planets orbiting Sun-like stars. We simulate the effects of forcing both eccentri…
197 Candidates and 104 Validated Planets in K2's First Five Fields
Ian J. M. Crossfield, David R. Ciardi, Erik A. Petigura +41
We present 197 planet candidates discovered using data from the first year of the NASA K2 mission (Campaigns 0-4), along with the results of an intensive program of photometric ana…
Friends of Hot Jupiters. IV. Stellar companions beyond 50 AU might facilitate giant planet formation, but most are unlikely to cause Kozai-Lidov migration
Henry Ngo, Heather A. Knutson, Sasha Hinkley +11
Stellar companions can influence the formation and evolution of planetary systems, but there are currently few observational constraints on the properties of planet-hosting binary…
Eleven Multi-planet Systems from K2 Campaigns 1 & 2 and the Masses of Two Hot Super-Earths
Evan Sinukoff, Andrew W. Howard, Erik A. Petigura +14
We present a catalog of 11 multi-planet systems from Campaigns 1 and 2 of the K2 mission. We report the sizes and orbits of 26 planets split between seven 2-planet systems and four…
Two Transiting Low Density Sub-Saturns from K2
Erik A. Petigura, Andrew W. Howard, Eric D. Lopez +11
We report the discovery and confirmation of two sub-Saturn planets orbiting a bright (V = 11.3), metal-rich ([Fe/H] = 0.42 0.04 dex) G3 dwarf in the K2 Campaign 2 field. The…
Two Transiting Earth-size Planets Near Resonance Orbiting a Nearby Cool Star
Erik A. Petigura, Joshua E. Schlieder, Ian J. M. Crossfield +11
Discoveries from the prime Kepler mission demonstrated that small planets (< 3 Earth-radii) are common outcomes of planet formation. While Kepler detected many such planets, all bu…