121 citations · 772 across the 28 of their papers we have counts for
28 papers
Orbits and Masses for 156 Companions from Combined Astrometry and Radial Velocities, and A Validation of Gaia Non-Single Star Solutions
Qier An, Timothy D. Brandt, G. Mirek Brandt +1
We combine absolute astrometry from Hipparcos and Gaia with archival radial velocities from the Keck/HIRES and ESO/HARPS spectrographs, as well as relative astrometry (when availab…
Discovery of the Binarity of Gliese 229B, and Constraints on the System's Properties
Samuel Whitebook, Timothy Brandt, Gregory Mirek Brandt +1
We present two epochs of radial velocities of the first imaged T dwarf Gliese 229B obtained with Keck/NIRSPEC. The two radial velocities are discrepant with one another, and with t…
Planet-Planet Scattering and ZLK Migration -- The Dynamical History of HAT-P-11
Tiger Lu, Qier An, Gongjie Li +4
The two planets of the HAT-P-11 system represent fascinating dynamical puzzles due to their significant eccentricities and orbital misalignments. In particular, HAT-P-11 b is on a…
Significant mutual inclinations between the stellar spin and the orbits of both planets in the HAT-P-11 system
Qier An, Tiger Lu, G. Mirek Brandt +2
Planet-star obliquity and planet-planet ]mutual inclination encode a planetary system's dynamical history, but both of their values are hard to measure for misaligned systems with…
Surveying Nearby Brown Dwarfs with HGCA: Direct Imaging Discovery of a Faint, High-Mass Brown Dwarf Orbiting HD 176535 A
Yiting Li, Timothy D. Brandt, G. Mirek Brandt +16
Brown dwarfs with well-measured masses, ages and luminosities provide direct benchmark tests of substellar formation and evolutionary models. We report the first results from a dir…
Automatic Spectroscopic Data Reduction using BANZAI
Curtis McCully, Matthew Daily, G. Mirek Brandt +3
Time domain astronomy has both increased the data volume and the urgency of data reduction in recent years. Spectra provide key insights into astrophysical phenomena but require co…
Direct Imaging and Astrometric Detection of a Gas Giant Planet Orbiting an Accelerating Star
Thayne Currie, G. Mirek Brandt, Timothy D. Brandt +31
Direct imaging of gas giant exoplanets provides key information on planetary atmospheres and the architectures of planetary systems. However, few planets have been detected in blin…
The McDonald Accelerating Stars Survey (MASS): Architecture of the Ancient Five-Planet Host System Kepler-444
Zhoujian Zhang, Brendan P. Bowler, Trent J. Dupuy +11
We present the latest and most precise characterization of the architecture for the ancient ( Gyr) Kepler-444 system, which is composed of a K0 primary star (Kepler-444…
Precise dynamical masses of new directly imaged companions from combining relative astrometry, radial velocities, and Hipparcos-Gaia eDR3 accelerations
E. L. Rickman, E. Matthews, W. Ceva +7
Aims. With an observing time span of more than 20 years, the CORALIE radial-velocity survey is able to detect long-term trends in data corresponding to companions with masses and s…
SCExAO and Keck Direct Imaging Discovery of a Low-Mass Companion Around the Accelerating F5 Star HIP 5319
Noah Swimmer, Thayne Currie, Sarah Steiger +26
We present the direct imaging discovery of a low-mass companion to the nearby accelerating F star, HIP 5319, using SCExAO coupled with the CHARIS, VAMPIRES, and MEC instruments in…
HD 83443c: A highly eccentric giant planet on a 22-year orbit
Adriana Errico, Robert A. Wittenmyer, Jonathan Horner +19
We report the discovery of a highly eccentric long-period Jovian planet orbiting the hot-Jupiter host HD\,83443. By combining radial velocity data from four instruments (AAT/UCLES,…
The Gliese 86 Binary System: A Warm Jupiter Formed in a Disk Truncated at 2 AU
Yunlin Zeng, Timothy D. Brandt, Gongjie Li +12
Gliese 86 is a nearby K dwarf hosting a giant planet on a 16-day orbit and an outer white dwarf companion on a century-long orbit. In this study we combine radial…
14 Her: a likely case of planet-planet scattering
Daniella C. Bardalez Gagliuffi, Jacqueline K. Faherty, Yiting Li +4
In this Letter, we measure the full orbital architecture of the two-planet system around the nearby K0 dwarf 14 Herculis. 14 Her (HD 145675, HIP 79248) is a middle-aged ($4.6^{+3.8…
Dynamical Mass of the Young Substellar Companion HD 984 B
Kyle Franson, Brendan P. Bowler, Timothy D. Brandt +5
Model-independent masses of substellar companions are critical tools to validate models of planet and brown dwarf cooling, test their input physics, and determine the formation and…
Limits on the Mass and Initial Entropy of 51 Eri b from Gaia EDR3 Astrometry
Trent J. Dupuy, G. Mirek Brandt, Timothy D. Brandt
51 Eri b is one of the only young planets consistent with a wide range of possible initial entropy states, including the cold-start scenario associated with some models of planet f…
Precise Masses and Orbits for Nine Radial Velocity Exoplanets
Yiting Li, Timothy D. Brandt, G. Mirek Brandt +6
Radial velocity (RV) surveys have discovered hundreds of exoplanetary systems but suffer from a fundamental degeneracy between planet mass and orbital inclination . In thi…
Improved Dynamical Masses for Six Brown Dwarf Companions Using Hipparcos and Gaia EDR3
G. Mirek Brandt, Trent J. Dupuy, Yiting Li +8
We present comprehensive orbital analyses and dynamical masses for the substellar companions Gl~229~B, Gl~758~B, HD~13724~B, HD~19467~B, HD~33632~Ab, and HD~72946~B. Our dynamical…
htof: A new open-source tool for analyzing Hipparcos, Gaia, and future astrometric missions
G. Mirek Brandt, Daniel Michalik, Timothy D. Brandt +3
We present htof, an open-source tool for interpreting and fitting the intermediate astrometric data (IAD) from both the 1997 and 2007 reductions of Hipparcos, the scanning-law of G…
A New Type of Exoplanet Direct Imaging Search: The SCExAO/CHARIS Survey of Accelerating Stars
Thayne Currie, Timothy Brandt, Masayuki Kuzuhara +12
We present first results from a new exoplanet direct imaging survey being carried out with the Subaru Coronagraphic Extreme Adaptive Optics project (SCExAO) coupled to the CHARIS i…
The First Dynamical Mass Measurement in the HR 8799 System
G. Mirek Brandt, Timothy D. Brandt, Trent J. Dupuy +2
HR 8799 hosts four directly imaged giant planets, but none has a mass measured from first principles. We present the first dynamical mass measurement in this planetary system, find…
The McDonald Accelerating Stars Survey (MASS): Discovery of a Long-Period Substellar Companion Orbiting the Old Solar Analog HD 47127
Brendan P. Bowler, Michael Endl, William D. Cochran +12
Brown dwarfs with well-determined ages, luminosities, and masses provide rare but valuable tests of low-temperature atmospheric and evolutionary models. We present the discovery an…
orvara: An Efficient Code to Fit Orbits using Radial Velocity, Absolute, and/or Relative Astrometry
Timothy D. Brandt, Trent J. Dupuy, Yiting Li +5
We present an open-source Python package, Orbits from Radial Velocity, Absolute, and/or Relative Astrometry (orvara), to fit Keplerian orbits to any combination of radial velocity,…
SCExAO/CHARIS Direct Imaging Discovery of a 20 au Separation, Low-Mass Ratio Brown Dwarf Companion to an Accelerating Sun-like Star
Thayne Currie, Timothy D. Brandt, Masayuki Kuzuhara +27
We present the direct imaging discovery of a substellar companion to the nearby Sun-like star, HD 33632 Aa, at a projected separation of 20 au, obtained with SCExAO/CHARIS i…
Precise Dynamical Masses and Orbital Fits for Pic b and Pic c
G. Mirek Brandt, Timothy D. Brandt, Trent J. Dupuy +2
We present a comprehensive orbital analysis to the exoplanets Pictoris b and c that resolves previously reported tensions between the dynamical and evolutionary mass constraint…