Eva-Maria Ahrer
A5008957090- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Atmospheric Ozone and Climate
- Astronomical Observations and Instrumentation
- Spectroscopy and Laser Applications
- Geophysics and Gravity Measurements
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Geology and Paleoclimatology Research
- Planetary Science and Exploration
- Gamma-ray bursts and supernovae
- Calibration and Measurement Techniques
- Conferences and Exhibitions Management
- High-pressure geophysics and materials
- Space Exploration and Technology
- Astronomical and nuclear sciences
- Career Development and Diversity
- Pulsars and Gravitational Waves Research
- Spacecraft Design and Technology
- Optical Polarization and Ellipsometry
- Spectroscopy Techniques in Biomedical and Chemical Research
- Leaf Properties and Growth Measurement
- Meteorological Phenomena and Simulations
Max Planck Institute for Astronomy
2024-2025
University of Warwick
2021-2024
University of Exeter
2024
University of Cambridge
2021
Transmission spectroscopy1-3 of exoplanets has revealed signatures water vapour, aerosols and alkali metals in a few dozen exoplanet atmospheres4,5. However, these previous inferences with the Hubble Spitzer Space Telescopes were hindered by observations' relatively narrow wavelength range spectral resolving power, which precluded unambiguous identification other chemical species-in particular primary carbon-bearing molecules6,7. Here we report broad-wavelength 0.5-5.5 µm atmospheric...
Measuring the abundances of carbon and oxygen in exoplanet atmospheres is considered a crucial avenue for unlocking formation evolution exoplanetary systems. Access to an exoplanet's chemical inventory requires high-precision observations, often inferred from individual molecular detections with low-resolution space-based high-resolution ground-based facilities. Here we report medium-resolution (R$\sim$600) transmission spectrum atmosphere between 3-5 $\mu$m covering multiple absorption...
Abstract Carbon dioxide (CO 2 ) is a key chemical species that found in wide range of planetary atmospheres. In the context exoplanets, CO an indicator metal enrichment (that is, elements heavier than helium, also called ‘metallicity’) 1–3 , and thus formation processes primary atmospheres hot gas giants 4–6 . It one most promising to detect secondary terrestrial exoplanets 7–9 Previous photometric measurements transiting planets with Spitzer Space Telescope have given hints presence but not...
Transmission spectroscopy provides insight into the atmospheric properties and consequently formation history, physics, chemistry of transiting exoplanets. However, obtaining precise inferences from transmission spectra requires simultaneously measuring strength shape multiple spectral absorption features a wide range chemical species. This has been challenging given precision wavelength coverage previous observatories. Here, we present spectrum Saturn-mass exoplanet WASP-39b obtained using...
Photochemistry is a fundamental process of planetary atmospheres that regulates the atmospheric composition and stability. However, no unambiguous photochemical products have been detected in exoplanet to date. Recent observations from JWST Transiting Exoplanet Early Release Science Program found spectral absorption feature at 4.05 $\mu$m arising SO$_2$ atmosphere WASP-39b. WASP-39b 1.27-Jupiter-radii, Saturn-mass (0.28 M$_J$) gas giant orbiting Sun-like star with an equilibrium temperature...
Abstract Measuring the metallicity and carbon-to-oxygen (C/O) ratio in exoplanet atmospheres is a fundamental step towards constraining dominant chemical processes at work and, if equilibrium, revealing planet formation histories. Transmission spectroscopy (for example, refs. 1,2 ) provides necessary means by abundances of oxygen- carbon-bearing species; however, this requires broad wavelength coverage, moderate spectral resolution high precision, which, together, are not achievable with...
Abstract Close-in giant exoplanets with temperatures greater than 2,000 K (‘ultra-hot Jupiters’) have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from Hubble Space Telescope (HST) and Spitzer 1–3 . However, previous studies yielded inconsistent results because small sizes spectral features limited information content data resulted in high sensitivity varying assumptions made treatment instrument systematics retrieval...
$\texttt{Eureka!}$ is a data reduction and analysis pipeline for exoplanet time-series observations, with particular focus on JWST data. Over the next 1-2 decades, will pursue four main science themes: Early Universe, Galaxies Time, Star Lifecycle, Other Worlds. Our providing astronomy community an open source tool of observations exoplanets in pursuit fourth these themes, The goal to provide end-to-end that starts uncalibrated FITS files ultimately yields precise spectra. has modular...
The recent inference of sulfur dioxide (SO2) in the atmosphere hot (approximately 1,100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations1-3 suggests that photochemistry is a key process high-temperature atmospheres4. This because low (<1 ppb) abundance SO2 under thermochemical equilibrium compared with produced H2O and H2S (1-10 ppm)4-9. However, was made single, small molecular feature transmission spectrum at 4.05 μm and, therefore, detection other absorption bands...
Abstract Hot Jupiters are among the best-studied exoplanets, but it is still poorly understood how their chemical composition and cloud properties vary with longitude. Theoretical models predict that clouds may condense on nightside molecular abundances can be driven out of equilibrium by zonal winds. Here we report a phase-resolved emission spectrum hot Jupiter WASP-43b measured from 5 μm to 12 JWST’s Mid-Infrared Instrument. The spectra reveal large day–night temperature contrast (with...
The newly operational JWST offers the potential to study atmospheres of distant worlds with precision that has not been achieved before. One first exoplanets observed by in summer 2022 was WASP-96 b, a hot-Saturn orbiting G8 star. As part Early Release Observations program, one transit b NIRISS/SOSS capture its transmission spectrum from 0.6-2.85 microns. In this work, we utilise four retrieval frameworks report precise and robust measurements b's atmospheric composition. We constrain...
Observing exoplanets through transmission spectroscopy supplies detailed information on their atmospheric composition, physics, and chemistry. Prior to JWST, these observations were limited a narrow wavelength range across the near-ultraviolet near-infrared, alongside broadband photometry at longer wavelengths. To understand more complex properties of exoplanet atmospheres, improved coverage resolution are necessary robustly quantify influence broader absorbing molecular species. Here we...
With sizable volatile envelopes but smaller radii than the solar system ice giants, sub-Neptunes have been revealed as one of most common types planet in galaxy. While spectroscopic characterization larger (2.5-4R$_\oplus$) has hydrogen-dominated atmospheres, (1.6--2.5R$_\oplus$) could either host thin, rapidly evaporating hydrogen-rich atmospheres or be stable metal-rich "water worlds" with high mean molecular weight and a fundamentally different formation evolutionary history. Here, we...
Even though sub-Neptunes likely represent the most common outcome of planet formation, their natures remain poorly understood. In particular, planets near 1.5-2.5$\,R_\oplus$ often have bulk densities that can be explained equally well with widely different compositions and interior structures, resulting in grossly divergent implications for formation. Here, we present full 0.6-5.2$\,\mu \mathrm{m}$ JWST NIRISS/SOSS+NIRSpec/G395H transmission spectrum 2.2$\,R_\oplus$ TOI-270d...
ABSTRACT We present an optical transmission spectrum for WASP-94A b, the first atmospheric characterization of this highly-inflated hot Jupiter. The planet has a reported radius $1.72^{+0.06}_{-0.05}$ RJup, mass only $0.456^{+0.032}_{-0.036}$ MJup, and equilibrium temperature 1508 ± 75 K. observed transit spectroscopically with EFOSC2 instrument on ESO New Technology Telescope (NTT) at La Silla, Chile: use NTT/EFOSC2 spectroscopy. achieved average transit-depth precision 128 ppm bin widths...
Abstract Carbon monoxide (CO) is predicted to be the dominant carbon-bearing molecule in giant planet atmospheres and, along with water, important for discerning oxygen and therefore carbon-to-oxygen ratio of these planets. The fundamental absorption mode CO has a broad, double-branched structure composed many individual lines from 4.3 5.1 μ m, which can now spectroscopically measured JWST. Here we present technique detecting rotational sub-band at medium resolution NIRSpec G395H instrument....
ABSTRACT Transport-induced quenching in hot Jupiter atmospheres is a process that determines the boundary between part of atmosphere at chemical equilibrium and thermochemical (but not photothermochemical) disequilibrium. The location this boundary, quench level, depends on interplay dynamical time-scales atmosphere, with occurring when these are equal. We explore sensitivity level position to an increase planet’s atmospheric metallicity using aerosol-free 3D general circulation model...
Sub-Neptunes are the most common type of planet in our galaxy. Interior structure models suggest that coldest sub-Neptunes could host liquid water oceans underneath their hydrogen envelopes - sometimes called 'hycean' planets. JWST transmission spectra $\sim$ 250 K sub-Neptune K2-18 b were recently used to report detections CH$_4$ and CO$_2$, alongside weaker evidence (CH$_3$)$_2$S (dimethyl sulfide, or DMS). Atmospheric CO$_2$ was interpreted as for a ocean, while DMS highlighted potential...
Abstract We present a transmission spectrum of the misaligned hot Jupiter WASP-15b from 2.8–5.2 microns observed with JWST’s NIRSpec/G395H grating. Our high signal to noise data, which has negligible red noise, reveals significant absorption by H2O (4.2σ) and CO2 (8.9σ). From independent data reduction atmospheric retrieval approaches, we infer that WASP-15b’s metallicity is super-solar (≳ 15 × solar) its C/O consistent solar, together imply planetesimal accretion. GCM simulations for...
Abstract The formation and migration history of a planet is expected to be imprinted in its atmosphere, particular carbon-to-oxygen (C/O) ratio metallicity. BOWIE-ALIGN programme performing comparative study JWST spectra four aligned misaligned hot Jupiters, with the aim characterising their atmospheres corroborating link between observables history. In this work, we present 2.8 − 5.2 micron transmission spectrum TrES-4 b, Jupiter an orbit rotation axis F-type host star. Using free chemistry...
Hot Jupiters are among the best-studied exoplanets, but it is still poorly understood how their chemical composition and cloud properties vary with longitude. Theoretical models predict that clouds may condense on nightside molecular abundances can be driven out of equilibrium by zonal winds. Here we report a phase-resolved emission spectrum hot Jupiter WASP-43b measured from 5-12 $μ$m JWST's Mid-Infrared Instrument (MIRI). The spectra reveal large day-night temperature contrast (with...
ABSTRACT We present a comprehensive analysis of 10 yr HARPS radial velocities (RVs) the K2V dwarf star HD 13808, which has previously been reported to host two unconfirmed planet candidates. use state-of-the-art nested sampling algorithm PolyChord compare wide variety stellar activity models, including simple models exploiting linear correlations between RVs and indicators, harmonic for signals, more sophisticated Gaussian process regression model. show that overly simplistic are not...
Carbon dioxide (CO2) is a key chemical species that found in wide range of planetary atmospheres. In the context exoplanets, CO2 an indicator metal enrichment (i.e., elements heavier than helium, also called "metallicity"), and thus formation processes primary atmospheres hot gas giants. It one most promising to detect secondary terrestrial exoplanets. Previous photometric measurements transiting planets with Spitzer Space Telescope have given hints presence but not yielded definitive...