natashabatalha/picaso: Release 2.1

Batalha, Natasha E.; M., Rooney, Caoimhe

doi:10.5281/zenodo.4206648

Cited by 10 publications

(4 citation statements)

References 0 publications

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“…Figure 4 shows low-resolving power (R ≡ λ/∆λ = 100) emission spectra for previously-shown thermal structure models (Figure 1) generated with the PICASO 1 (Batalha et al 2019;Batalha & Rooney 2020). As before, adopted models bracket the effective temperatures explored here (i.e., 350 K and 200 K) and assume log g of 4.…”

Section: Model Spectramentioning

confidence: 97%

Impacts of Water Latent Heat on the Thermal Structure of Ultra-Cool Objects: Brown Dwarfs and Free-Floating Planets

Tang,

Robinson,

Marley

et al. 2021

Preprint

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Brown dwarfs are essential targets for understanding planetary and sub-stellar atmospheres across a wide range of thermal and chemical conditions. As surveys continue to probe ever deeper, and as observing capabilities continue to improve, the number of known Y dwarfs -the coldest class of substellar objects, with effective temperatures below about 600 K -is rapidly growing. Critically, this class of ultra-cool objects has atmospheric conditions that overlap with Solar System worlds and, as a result, tools and ideas developed from studying Earth, Jupiter, Saturn and other nearby worlds are well-suited for application to sub-stellar atmospheres. To that end, we developed a one-dimensional (vertical) atmospheric structure model for ultra-cool objects that includes moist adiabatic convection, as this is an important process for many Solar System planets. Application of this model across a range of effective temperatures (350, 300, 250, 200 K), metallicities ([M/H] of 0.0, 0.5, 0.7, 1.5), and gravities (log g of 4.0, 4.5, 4.7, 5.0) demonstrates strong impacts of water latent heat release on simulated temperature-pressure profiles. At the highest metallicities, water vapor mixing ratios reach an Earth-like 3%, with associated major alterations to the thermal structure in the atmospheric regions where water condenses. Spectroscopic and photometric signatures of metallicity and moist convection should be readily detectable at near-and mid-infrared wavelengths, especially with James Webb Space Telescope observations, and can help indicate the formation history of an object.

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Section: Model Spectramentioning

confidence: 97%

Impacts of Water Latent Heat on the Thermal Structure of Ultra-Cool Objects: Brown Dwarfs and Free-Floating Planets

Tang,

Robinson,

Marley

et al. 2021

Preprint

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“…With the given prescription for atmospheric abundances and temperature-pressure profiles, we use the PICASO radiative transfer tool (Batalha et al 2019;Batalha & Rooney 2020) to compute the transmission spectra. Of importance for this analysis are the opacities of H 2 O, CH 4 and CO 2 , for which we use Polyansky et al (2018), Yurchenko & Tennyson (2014), and Huang et al (2014), respectively.…”

Section: Modeling Spectra and Retrieving Abundancesmentioning

confidence: 99%

Importance of Sample Selection in Exoplanet-atmosphere Population Studies

Batalha

Wolfgang²,

Teske

et al. 2022

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Understanding planet formation requires robust population studies, which are designed to reveal trends in planet properties. In this work we aim to determine if and how different methods for selecting populations of exoplanets for atmospheric characterization with JWST could influence population-level inferences. We generate three hypothetical surveys of super-Earths/sub-Neptunes, with each survey designed to span a similar radius-insolation flux space. The survey samples are constructed based on three different selection criteria (evenly spaced by eye, binned, and a quantitative selection function). Using an injection-recovery technique, we test how robustly individual-planet atmospheric parameters and population-level parameters can be retrieved. We find that all three survey designs result in equally suitable targets for individual atmospheric characterization, but not equally suitable targets for constraining population parameters. Only samples constructed with a quantitative method or that are sufficiently evenly spaced-by-eye result in robust population parameter constraints. Furthermore, we find that the sample with the best targets for individual atmospheric study does not necessarily result in the best-constrained population parameters. The method of sample selection must be considered. We also find that there may be large variability in population-level results with a sample that is small enough to fit in a single JWST cycle (∼12 planets), suggesting that the most successful population-level analyses will be multicycle. Lastly, we infer that our exploration of sample selection is limited by the small number of transiting planets with measured masses around bright stars. Our results can guide future development of programs that aim to determine underlying trends in exoplanet-atmospheric properties, and, by extension, formation and evolution processes.

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“…First, we will post a 5 Gb resampled version of the database on Zenodo, due to their file size limitations. The Zenodo database will be in the same format as the (Freedman et al 2014) database currently used by PICASO (Batalha et al 2019;Batalha & Rooney 2020) 29 . Second, the full unsampled database (MySQL format) will be available via an FTP-like portal.…”

Section: Supplementary Datamentioning

confidence: 99%

EXOPLINES: Molecular Absorption Cross-Section Database for Brown Dwarf and Giant Exoplanet Atmospheres

Gharib-Nezhad,

Iyer,

Line

et al. 2021

Preprint

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Stellar, substellar, and planetary atmosphere models are all highly sensitive to the input opacities. Generational differences between various state-of-the-art stellar/planetary models are primarily because of incomplete and outdated atomic/molecular line-lists. Here we present a database of precomputed absorption cross-sections for all isotopologues of key atmospheric molecules relevant to latetype stellar, brown dwarf, and planetary atmospheres: MgH, AlH, CaH, TiH, CrH, FeH, SiO, TiO, VO, and H 2 O. The pressure and temperature ranges of the computed opacities are between 10 −6 -3000 bar and 75-4000 K, and their spectral ranges are 0.25-330 µm for many cases where possible. For cases with no pressure-broadening data, we use collision theory to bridge the gap. We also probe the effect of absorption cross-sections calculated from different line lists in the context of Ultra-Hot Jupiter and M-dwarf atmospheres. Using 1-D self-consistent radiative-convective thermochemical equilibrium models, we report significant variations in the theoretical spectra and thermal profiles of substellar atmospheres. With a 2000 K representative Ultra-Hot Jupiter, we report variations of up to 320 and 80 ppm in transmission and thermal emission spectra, respectively. For a 3000 K M-dwarf, we find differences of up to 125% in the spectra. We find that the most significant differences arise due to the choice of TiO line-lists, primarily below 1µm. In sum, we present (1) a database of pre-computed molecular absorption cross-sections, and (2) quantify biases that arise when characterizing substellar/exoplanet atmospheres due to line list differences, therefore highlighting the importance of correct and complete opacities for eventual applications to high precision spectroscopy and photometry.

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natashabatalha/picaso: Release 2.1

Cited by 10 publications

References 0 publications

Impacts of Water Latent Heat on the Thermal Structure of Ultra-Cool Objects: Brown Dwarfs and Free-Floating Planets

Impacts of Water Latent Heat on the Thermal Structure of Ultra-Cool Objects: Brown Dwarfs and Free-Floating Planets

Importance of Sample Selection in Exoplanet-atmosphere Population Studies

EXOPLINES: Molecular Absorption Cross-Section Database for Brown Dwarf and Giant Exoplanet Atmospheres

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