Gregory J. Gilbert
A5056189875- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Planetary Science and Exploration
- Astronomical Observations and Instrumentation
- Scientific Research and Discoveries
- Radio Astronomy Observations and Technology
- Gamma-ray bursts and supernovae
- Methane Hydrates and Related Phenomena
- Space Satellite Systems and Control
- Spaceflight effects on biology
- Remote Sensing and LiDAR Applications
- Molecular spectroscopy and chirality
- Satellite Image Processing and Photogrammetry
University of California, Los Angeles
2022-2025
University of Chicago
2016-2022
ABSTRACT A gold standard for the study of M dwarfs is eclipsing binary CM Draconis. It rare because it bright (Jmag = 8.5) and contains twin fully convective stars on an almost perfectly edge-on orbit. Both masses radii were previously measured to better than 1 per cent precision, amongst best known. We use 15 sectors data from Transiting Exoplanet Survey Satellite (TESS) show that Draconis gift keeps giving. Our paper has three main components. First, we present updated parameters, with...
Abstract TOI-6255 b (GJ 4256) is an Earth-sized planet (1.079 ± 0.065 R ⊕ ) with orbital period of only 5.7 hr. With the newly commissioned Keck Planet Finder and CARMENES spectrographs, we determine planet’s mass to be 1.44 0.14 M . The just outside Roche limit, P orb / = 1.13 0.10. strong tidal force likely deforms into a triaxial ellipsoid long axis that ∼10% longer than short axis. Assuming reduced stellar quality factor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
Abstract Multiple planets undergoing disk migration may be captured into a chain of mean-motion resonances with the innermost planet parked near disk’s inner edge. Subsequent dynamical evolution disrupt these resonances, leading to nonresonant configurations typically observed among Kepler that are Gyr old. In this scenario, resonant expected more common in younger systems. This prediction can now tested, thanks recent discoveries young planets, particular those stellar clusters, by NASA’s...
We propose several descriptive measures to characterize the arrangements of planetary masses, periods, and mutual inclinations within exoplanetary systems. These are based in complexity theory capture global, system-level trends each architecture. Our approach considers all planets a system simultaneously, facilitating both intra-system inter-system analysis. find that on these measures, Kepler's high-multiplicity ($N\geq3$) systems can be explained if most belong single intrinsic...
NASA's Kepler mission identified over 4,000 extrasolar planets that transit (cross in front of) their host stars. This sample has revealed detailed features the demographics of planet sizes and orbital spacings. However, knowledge shapes-a key tracer planetary formation evolution-remains far more limited. We present measurements eccentricities for 1,646 planets, 92% which are smaller than Neptune. For all sizes, eccentricity distribution peaks at e = 0 falls monotonically toward zero 1. As...
ABSTRACT The characterization of a physically diverse set transiting exoplanets is an important and necessary step toward establishing the physical properties linked to production obscuring clouds or hazes. It those planets with identifiable spectroscopic features that can most effectively enhance our understanding atmospheric chemistry metallicity. newly commissioned LDSS-3C instrument on Magellan provides enhanced sensitivity suppressed fringing in red optical, thus advancing search for...
Abstract We present the Distant Giants Survey, a three-year radial velocity campaign to measure P(DG∣CS), conditional occurrence of distant giant planets (DG; M p ∼ 0.3–13 J , P > 1 yr) in systems hosting close-in small planet (CS; R < 10 ⊕ ). For past two years, we have monitored 47 Sun-like stars transiting detected by TESS. selection criteria used assemble our sample and report discovery planets, TOI-1669 b TOI-1694 c. find that <?CDATA $M\sin i=0.573\pm 0.074\,\,{M}_{{\rm{J}}}$?>...
Abstract We present the stellar and planetary properties for 85 TESS Objects of Interest (TOIs) hosting 108 planet candidates that compose TESS-Keck Survey (TKS) sample. combine photometry, high-resolution spectroscopy, Gaia parallaxes to measure precise accurate properties. then use these parameters as inputs a light-curve processing pipeline recover signals homogeneously fit their transit Among fits, we detect significant transit-timing variations among at least three multiplanet systems...
Grazing transits present a special problem for statistical studies of exoplanets. Even though grazing planetary orbits are rare (due to geometric selection effects), many low moderate signal-to-noise cases, significant fraction the posterior distribution is nonetheless consistent with geometry. A failure accurately model can therefore lead biased inferences even cases where planet not actually on trajectory. With recent advances in stellar characterization, limiting factor scientific...
Multiple planets undergoing disk migration may be captured into a chain of mean-motion resonances with the innermost planet parked near disk's inner edge. Subsequent dynamical evolution disrupt these resonances, leading to non-resonant configurations typically observed among {\it Kepler} that are Gyrs old. In this scenario, resonant expected more common in younger systems. This prediction can now tested, thanks recent discoveries young planets, particularly those stellar clusters, by NASA's...
Hundreds of exoplanets between 1-1.8 times the size Earth have been discovered on close in orbits. However, these planets show such a diversity densities that some appear to be made entirely iron, while others host gaseous envelopes. To test this composition, we update masses 5 rocky (HD 93963 A b, Kepler-10 Kepler-100 Kepler-407 and TOI-1444 b) present confirmation new planet (TOI-1011) using 187 high precision RVs from Gemini/MAROON-X Keck/KPF. Our updated suggest compositions closer than...
A gold standard for the study of M dwarfs is eclipsing binary CM Draconis. It rare because it bright ($J_{\rm mag}=8.5$) and contains twin fully convective stars on an almost perfectly edge-on orbit. Both masses radii were previously measured to better than $1\%$ precision, amongst best known. We use 15 sectors data from Transiting Exoplanet Survey Satellite (TESS) show that Draconis gift keeps giving. Our paper has three main components. First, we present updated parameters, with...
Abstract The transit technique is responsible for the majority of exoplanet discoveries to date. Characterizing these planets involves careful modeling their profiles. A common expressing duration using a density-like parameter, <?CDATA $\tilde{\rho }$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mrow> <mml:mi>ρ</mml:mi> </mml:mrow> <mml:mo>˜</mml:mo> </mml:mover> </mml:math> , often called “circular density.” Most notably,...
Second-order mean-motion resonances lead to an interesting phenomenon in the sculpting of period ratio distribution due their shape and width period-ratio/eccentricity space. As osculating periods librate resonance, time-averaged approaches exact commensurability. The second-order increases with increasing eccentricity, thus more eccentric systems have a stronger peak at commensurability when averaged over sufficient time. libration is short enough that this time-averaging behavior expected...
A planet's orbital eccentricity is fundamental to understanding the present dynamical state of a system and relic its formation history. There high scientific value in measuring eccentricities Kepler TESS planets given sheer size these samples diversity their planetary systems. However, lightcurves typically only permit robust determinations planet-to-star radius ratio $r$, period $P$, transit mid-point $t_0$. Three other properties, including impact parameter $b$, $e$, argument periastron...
TOI-6255~b (GJ 4256) is an Earth-sized planet (1.079$\pm0.065$ $R_\oplus$) with orbital period of only 5.7 hours. With the newly commissioned Keck Planet Finder (KPF) and CARMENES spectrographs, we determined planet's mass to be 1.44$\pm$0.14 $M_{\oplus}$. The just outside Roche limit, $P_{\rm orb}/P_{\rm Roche}$ = 1.13 $\pm0.10$. strong tidal force likely deforms into a triaxial ellipsoid long axis that $\sim$10\% longer than short axis. Assuming reduced stellar quality factor...
We present the stellar and planetary properties for 85 TESS Objects of Interest (TOIs) hosting 108 planet candidates which comprise TESS-Keck Survey (TKS) sample. combine photometry, high-resolution spectroscopy, Gaia parallaxes to measure precise accurate properties. then use these parameters as inputs a lightcurve processing pipeline recover signals homogeneously fit their transit Among fits, we detect significant transit-timing variations among at least three multi-planet systems...
A planet's orbital eccentricity is fundamental to understanding the present dynamical state of a system and relic its formation history. There high scientific value in measuring eccentricities Kepler TESS planets given sheer size these samples diversity their planetary systems. However, lightcurves typically only permit robust determinations planet-to-star radius ratio $r$, period $P$, transit mid-point $t_0$. Three other properties, including impact parameter $b$, $e$, argument periastron...
We present the Distant Giants Survey, a three-year radial velocity (RV) campaign to measure P(DG|CS), conditional occurrence of distant giant planets (DG; M_p ~ 0.3 - 13 M_J, P > 1 year) in systems hosting close-in small planet (CS; R_p < 10 R_E). For past two years, we have monitored 47 Sun-like stars transiting detected by TESS. selection criteria used assemble our sample and report discovery planets, TOI-1669 b TOI-1694 c. find that Msin i = 0.573 +/- 0.074 502 16 days, e 0.27,...