22 citations · 98 across the 22 of their papers we have counts for
22 papers
Fitting Moving Objects in Up-The-Ramp Data with Applications to the Roman Space Telescope and JWST
Timothy D. Brandt
A moving object breaks the fundamental property of constant per-pixel count rates in an astronomical image read out up-the-ramp. In this paper, we show how to fit a moving object's…
Spatially-Resolved Spectra of Diffuse Galactic Light using 10.8 M DESI Sky Fibers
Andrew K. Saydjari, Bruce T. Draine, Timothy D. Brandt +49
Using 10.8 million ``blank'' sky spectra from the DESI Year 3 dataset, we measure the diffuse galactic light (DGL) spectrum in the optical at spectral resolution by c…
A New Sirius-like System at Only 21 Parsecs: An Elusive White Dwarf Companion to the Nearby K-dwarf HD 38230
Alexander Venner, Logan A. Pearce, Qier An +6
White dwarfs are among the rarest and faintest stars found in the solar neighbourhood and are therefore persistently challenging to detect. Whereas the \textit{Gaia} mission has va…
The Architecture of the 14 Herculis System Suggests Primordial Ejection of a Massive Planet
Tiger Lu, Sarah C. Millholland, Malena Rice +6
The 14 Herculis system hosts two super-Jupiters on eccentric, significantly misaligned orbits. This orbital architecture represents a dynamical puzzle that demands explanation. In…
A carbon-rich atmosphere on a windy pulsar planet
Michael Zhang, Maya Beleznay, Timothy D. Brandt +17
A handful of enigmatic Jupiter-mass objects have been discovered orbiting pulsars. One such object, PSR\,J2322-2650b, uniquely resembles a hot Jupiter exoplanet due to its minimum…
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…
The Roman Space Telescope as a Planetary Defense Asset
Bryan J. Holler, Richard G. Cosentino, William C. Schultz +5
NASA's Nancy Grace Roman Space Telescope, slated to launch in October 2026, will serve a critical role in the characterization and threat assessment of near-Earth Objects (NEOs), t…
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…
JWST Coronagraphic Images of 14 Her c: a Cold Giant Planet in a Dynamically Hot, Multi-planet System
Daniella C. Bardalez Gagliuffi, William O. Balmer, Laurent Pueyo +16
Most observed multi-planet systems are coplanar, in a dynamically "cold" configuration of concentric orbits like our own Solar System. With the James Webb Space Telescope (JWST) we…
Effects of Jump Detection and Ramp Fitting Algorithms on NIRISS/SOSS Exoplanet Time-Series Observations
Aarynn Carter, Néstor Espinoza, Loïc Albert +4
Jump detection and ramp fitting are fundamental steps when elevating JWST data products from up-the-ramp measurements to integration level count rate images. Occurring at an early…
HD 28185 Revisited: An Outer Planet, Instead of a Brown Dwarf, On a Saturn-like Orbit
Alexander Venner, Qier An, Chelsea X. Huang +3
As exoplanet surveys reach ever-higher sensitivities and durations, planets analogous to the solar system giant planets are increasingly within reach. HD 28185 is a Sun-like star k…
Astrometry as a Tool for Discovering and Weighing Faint Companions to Nearby Stars
Timothy D. Brandt
This tutorial covers the use of absolute astrometry, in particular from the combination of the Hipparcos and Gaia missions, to identify faint companions to nearby stars and to meas…
JWST/NIRCam 4-5 m Imaging of the Giant Planet AF Lep b
Kyle Franson, William O. Balmer, Brendan P. Bowler +23
With a dynamical mass of , the recently discovered giant planet AF Lep b is the lowest-mass imaged planet with a direct mass measurement. Its youth and spectra…
Accurate and Model Independent Radius Determination of Single FGK and M Dwarfs Using Gaia DR3 Data
Rocio Kiman, Timothy D. Brandt, Jacqueline K. Faherty +1
Measuring fundamental stellar parameters is key to fully comprehending the evolution of stars. However, current theoretical models over-predict effective temperatures, and under-pr…
Gliese 12 b: A temperate Earth-sized planet at 12 pc ideal for atmospheric transmission spectroscopy
M. Kuzuhara, A. Fukui, J. H. Livingston +103
Recent discoveries of Earth-sized planets transiting nearby M dwarfs have made it possible to characterize the atmospheres of terrestrial planets via follow-up spectroscopic observ…
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…
Likelihood-Based Jump Detection and Cosmic Ray Rejection for Detectors Read Out Up-the-Ramp
Timothy D. Brandt
This paper implements likelihood-based jump detection for detectors read out up-the-ramp, using the entire set of reads to compute likelihoods. The approach compares the valu…
Direct-imaging Discovery of a Substellar Companion Orbiting the Accelerating Variable Star, HIP 39017
Taylor L. Tobin, Thayne Currie, Yiting Li +23
We present the direct-imaging discovery of a substellar companion (a massive planet or low-mass brown dwarf) to the young, Doradus-type variable star, HIP 39017 (HD 65526). The…
Revised Architecture and Two New Super-Earths in the HD 134606 Planetary System
Zhexing Li, Stephen R. Kane, Timothy D. Brandt +15
Multi-planet systems exhibit a diversity of architectures that diverge from the solar system and contribute to the topic of exoplanet demographics. Radial velocity (RV) surveys for…
Two long-period giant planets around two giant stars: HD 112570 and HD 154391
Guang-Yao Xiao, Huan-Yu Teng, Jianzhao Zhou +24
We present the discoveries of two giant planets orbiting the red giant branch (RGB) star HD 112570 and the red clump (RC) star HD 154391, based on the radial velocity (RV) measurem…
Optimal Fitting and Debiasing for Detectors Read Out Up-the-Ramp
Timothy D. Brandt
This paper derives the optimal fit to a pixel's count rate in the case of an ideal detector read out nondestructively in the presence of both read and photon noise. The approach is…