Jacob L. Bean
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View article: The JWST Rocky Worlds DDT Program Reveals GJ 3929b to Likely Be a Bare Rock
The JWST Rocky Worlds DDT Program Reveals GJ 3929b to Likely Be a Bare Rock Open
We report first results from the JWST Rocky Worlds Director’s Discretionary Time program. Two secondary eclipses of the terrestrial exoplanet GJ 3929b were recently observed using MIRI photometric imaging at 15 μ m. We present a reduction …
View article: A Stellar Magnesium to Silicon ratio in the atmosphere of an exoplanet
A Stellar Magnesium to Silicon ratio in the atmosphere of an exoplanet Open
The elemental compositions of exoplanets encode information about their formation environments and internal structures. While volatile ratios such as carbon-to-oxygen (C/O) are used to trace formation location, the rock-forming elements - …
View article: An Earthlike Density for the Temperate Earth-sized Planet GJ 12 b
An Earthlike Density for the Temperate Earth-sized Planet GJ 12 b Open
While JWST has provided us with the opportunity to probe the atmospheres of potentially habitable planets, observations of the TRAPPIST-1 system have shown us that active stars severely complicate efforts at studying their planets. GJ 12 b…
View article: Aligned Stellar Obliquities for Two Hot Jupiter-hosting M Dwarfs Revealed by MAROON-X: Implications for Hot Jupiter Formation
Aligned Stellar Obliquities for Two Hot Jupiter-hosting M Dwarfs Revealed by MAROON-X: Implications for Hot Jupiter Formation Open
Hot Jupiters (HJs) are 2–3× less common around M dwarfs than around AFGK stars, suggesting that HJs may form and/or migrate via distinct pathways around different types of stars. One source of insight into HJ formation mechanisms is to tra…
View article: Horizontal and vertical exoplanet thermal structure from a JWST spectroscopic eclipse map
Horizontal and vertical exoplanet thermal structure from a JWST spectroscopic eclipse map Open
View article: A carbon-rich atmosphere on a windy pulsar planet
A carbon-rich atmosphere on a windy pulsar planet Open
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 density of 1.8 g/cm^3 and its ~1900 K equilibrium temperatu…
View article: An Aligned Sub-Neptune Revealed with MAROON-X and a Tendency Toward Alignment for Small Planets
An Aligned Sub-Neptune Revealed with MAROON-X and a Tendency Toward Alignment for Small Planets Open
We present the Rossiter–McLaughlin measurement of the sub-Neptune TOI-1759A b with MAROON-X. A joint analysis with MuSCAT3 photometry and nine additional TESS transits produces a sky-projected obliquity of ∣ λ ∣ = 4° ± 18°. We also derive …
View article: Aligned Stellar Obliquities for Two Hot Jupiter-hosting M Dwarfs Revealed by MAROON-X: Implications for Hot Jupiter Formation
Aligned Stellar Obliquities for Two Hot Jupiter-hosting M Dwarfs Revealed by MAROON-X: Implications for Hot Jupiter Formation Open
Hot Jupiters (HJs) are $2-3\times$ less common around early M dwarfs than around AFGK stars, suggesting that HJs may form and/or migrate via distinct pathways around different types of stars. One source of insight into HJ formation mechani…
View article: The JWST Rocky Worlds DDT Program reveals GJ 3929b to likely be a bare rock
The JWST Rocky Worlds DDT Program reveals GJ 3929b to likely be a bare rock Open
We report first results from the JWST Rocky Worlds Director's Discretionary Time program. Two secondary eclipses of the terrestrial exoplanet GJ 3929b were recently observed using MIRI photometric imaging at 15 um. We present a reduction o…
View article: A Metal-poor Atmosphere with a Hot Interior for a Young Sub-Neptune Progenitor: JWST/NIRSpec Transmission Spectrum of V1298 Tau b
A Metal-poor Atmosphere with a Hot Interior for a Young Sub-Neptune Progenitor: JWST/NIRSpec Transmission Spectrum of V1298 Tau b Open
We present the JWST/NIRSpec G395H transmission spectrum of the young (10–30 Myr) transiting planet V1298 Tau b (9.85 ± 0.35 R ⊕ , T eq = 670 K). Combined Hubble Space Telescope and JWST observations reveal a haze-free, H/He-dominated atmos…
View article: Reproduction package for the paper "A metal-poor atmosphere with a hot interior for a young sub-Neptune progenitor: JWST/NIRSpec transmission spectrum of V1298 Tau b"
Reproduction package for the paper "A metal-poor atmosphere with a hot interior for a young sub-Neptune progenitor: JWST/NIRSpec transmission spectrum of V1298 Tau b" Open
Brief reproduction package for the paper entitled "A metal-poor atmosphere with a hot interior for a young sub-Neptune progenitor: JWST/NIRSpec transmission spectrum of V1298 Tau b"
View article: Insufficient evidence for DMS and DMDS in the atmosphere of K2-18 b
Insufficient evidence for DMS and DMDS in the atmosphere of K2-18 b Open
Context . Recent JWST observations of the temperate sub-Neptune K2-18 b have been interpreted as suggestive of a liquid water ocean with possible biological activity. Signatures of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) have …
View article: The Compositions of Rocky Planets in Close-in Orbits Tend to Be Earth-like
The Compositions of Rocky Planets in Close-in Orbits Tend to Be Earth-like Open
Hundreds of exoplanets between 1 and 1.8 times the size of Earth have been discovered on close-in orbits. However, these planets show such a diversity in densities that some appear to be made entirely of iron, while others appear to host g…
View article: The Roasting Marshmallows Program with IGRINS on Gemini South III: Seeing deeper into the metal depleted atmosphere of a gas-giant on the cusp of the hot to ultra-hot Jupiter transition
The Roasting Marshmallows Program with IGRINS on Gemini South III: Seeing deeper into the metal depleted atmosphere of a gas-giant on the cusp of the hot to ultra-hot Jupiter transition Open
Ultra-hot Jupiters (dayside temperatures Tday>2200 K) are a class of gas-giant exoplanets that, due to extreme stellar irradiation, show a peculiar combination of thermochemical properties in the form of molecular dissociation, atomic i…
View article: The Roasting Marshmallows Program with IGRINS on Gemini South III: Seeing deeper into the metal depleted atmosphere of a gas-giant on the cusp of the hot to ultra-hot Jupiter transition
The Roasting Marshmallows Program with IGRINS on Gemini South III: Seeing deeper into the metal depleted atmosphere of a gas-giant on the cusp of the hot to ultra-hot Jupiter transition Open
Ultra-hot Jupiters are a class of gas-giant exoplanets that show a peculiar combination of thermochemical properties in the form of molecular dissociation, atomic ionization, and inverted thermal structures. Atmospheric characterization of…
View article: An Aligned Sub-Neptune Revealed with MAROON-X and a Tendency Towards Alignment for Small Planets
An Aligned Sub-Neptune Revealed with MAROON-X and a Tendency Towards Alignment for Small Planets Open
We present the Rossiter-McLaughlin measurement of the sub-Neptune TOI-1759A b with MAROON-X. A joint analysis with MuSCAT3 photometry and nine additional TESS transits produces a sky-projected obliquity of $|λ|$= $4^\circ\pm18^{\circ}$. We…
View article: An Earth-like Density for the Temperate Earth-sized Planet GJ 12b
An Earth-like Density for the Temperate Earth-sized Planet GJ 12b Open
While JWST has provided us with the opportunity to probe the atmospheres of potentially-habitable planets, observations of the TRAPPIST-1 system have shown us that active stars severely complicate efforts at studying their planets. GJ 12b …
View article: Population-level Hypothesis Testing with Rocky Planet Emission Data: A Tentative Trend in the Brightness Temperatures of M-Earths
Population-level Hypothesis Testing with Rocky Planet Emission Data: A Tentative Trend in the Brightness Temperatures of M-Earths Open
Determining which rocky exoplanets have atmospheres, and why, is a key goal for the James Webb Space Telescope. So far, emission observations of individual rocky exoplanets orbiting M stars (M-Earths) have not provided definitive evidence …
View article: A Dark, Bare Rock for TOI-1685 b from a JWST NIRSpec G395H Phase Curve
A Dark, Bare Rock for TOI-1685 b from a JWST NIRSpec G395H Phase Curve Open
We report JWST NIRSpec/G395H observations of TOI-1685 b, a hot rocky super-Earth orbiting an M2.5V star, during a full orbit. We obtain transmission and emission spectra of the planet and characterize the properties of the phase curve, inc…
View article: The Radiative Effects of Photochemical Hazes on the Atmospheric Circulation and Phase Curves of Sub-Neptunes
The Radiative Effects of Photochemical Hazes on the Atmospheric Circulation and Phase Curves of Sub-Neptunes Open
Measuring the atmospheric composition of hazy sub-Neptunes like GJ 1214b through transmission spectroscopy is difficult because of the degeneracy between mean molecular weight (MMW) and haziness. It has been proposed that phase-curve obser…
View article: TOI-421 b: A Hot Sub-Neptune with a Haze-free, Low Mean Molecular Weight Atmosphere
TOI-421 b: A Hot Sub-Neptune with a Haze-free, Low Mean Molecular Weight Atmosphere Open
Common features of sub-Neptune atmospheres observed to date include signatures of aerosols at moderate equilibrium temperatures (∼500–800 K) and a prevalence of high mean molecular weight atmospheres, perhaps indicating novel classes of pl…
View article: An Analysis of Spitzer Phase Curves for WASP-121b and WASP-77Ab
An Analysis of Spitzer Phase Curves for WASP-121b and WASP-77Ab Open
We present analyses of Spitzer InfraRed Array Camera (IRAC) 3.6 μ m and 4.5 μ m phase-curve observations of hot Jupiters WASP-77Ab and WASP-121b. For WASP-121b, we find amplitudes of 1771 ± 95 ppm (3.6 μ m) and 2048 ± 109 ppm (4.5 μ m), an…
View article: Calibrating the Instrumental Drift in MAROON-X Using an Ensemble Analysis
Calibrating the Instrumental Drift in MAROON-X Using an Ensemble Analysis Open
MAROON-X is a state-of-the-art extreme-precision radial velocity spectrograph deployed on the 8.1 m Gemini-N telescope on Maunakea, Hawai’i. Using a stabilized Fabry–Pérot etalon for wavelength and drift calibration, MAROON-X has achieved …
View article: The radiative effects of photochemical hazes on the atmospheric circulation and phase curves of sub-Neptunes
The radiative effects of photochemical hazes on the atmospheric circulation and phase curves of sub-Neptunes Open
Measuring the atmospheric composition of hazy sub-Neptunes like GJ~1214b through transmission spectroscopy is difficult because of the degeneracy between mean molecular weight and haziness. It has been proposed that phase curve observation…
View article: Clouds and Hazes in GJ 1214 b’s Metal-rich Atmosphere
Clouds and Hazes in GJ 1214 b’s Metal-rich Atmosphere Open
The sub-Neptune GJ 1214 b has an infamously flat transmission spectrum, likely due to thick aerosols in its atmosphere. A recent JWST/MIRI spectroscopic phase curve of GJ 1214 b added to this picture, suggesting a highly reflective and met…
View article: Constraining Atmospheric Composition from the Outflow: Helium Observations Reveal the Fundamental Properties of Two Planets Straddling the Radius Gap
Constraining Atmospheric Composition from the Outflow: Helium Observations Reveal the Fundamental Properties of Two Planets Straddling the Radius Gap Open
TOI-836 is a ∼2–3 Gyr K dwarf with an inner super Earth ( R = 1.7 R ⊕ , P = 3.8 days) and an outer mini-Neptune ( R = 2.6 R ⊕ , P = 8.6 days). JWST/NIRSpec 2.8–5.2 μ m transmission spectra are flat for both planets. We present Keck/NIRSPEC…
View article: Four Sub-Earth Planets Orbiting Barnard’s Star from MAROON-X and ESPRESSO
Four Sub-Earth Planets Orbiting Barnard’s Star from MAROON-X and ESPRESSO Open
Barnard’s Star is an old, single M dwarf star that comprises the second-closest extrasolar system. It has a long history of claimed planet detections from both radial velocities and astrometry. However, none of these claimed detections hav…
View article: Four sub-Earth planets orbiting Barnard's Star from MAROON-X and ESPRESSO
Four sub-Earth planets orbiting Barnard's Star from MAROON-X and ESPRESSO Open
Barnard's Star is an old, single M dwarf star that comprises the second-closest extrasolar system. It has a long history of claimed planet detections from both radial velocities and astrometry. However, none of these claimed detections hav…
View article: Calibrating the Instrumental Drift in MAROON-X using an Ensemble Analysis
Calibrating the Instrumental Drift in MAROON-X using an Ensemble Analysis Open
MAROON-X is a state-of-the-art extreme precision radial velocity spectrograph deployed on the 8.1-meter Gemini-N telescope on Maunakea, Hawai'i. Using a stabilized Fabry-Pérot etalon for wavelength and drift calibration, MAROON-X has achie…
View article: Peering into the Black Box: Forward Modeling of the Uncertainty Budget of High-resolution Spectroscopy of Exoplanet Atmospheres
Peering into the Black Box: Forward Modeling of the Uncertainty Budget of High-resolution Spectroscopy of Exoplanet Atmospheres Open
Ground-based high-resolution cross-correlation spectroscopy (HRCCS; R ≳ 15,000) is a powerful complement to space-based studies of exoplanet atmospheres. By resolving individual spectral lines, HRCCS can precisely measure chemical abundanc…