Doing the *: Performing the Radical in Antisexist and Antiracist Work

The essay summarizes excerpts from the 6th Biennial Seneca Falls Dialogue’s (SFD) session, “Doing the *: Performing the Radical in Antisexist and Antiracist Work.” In this dialogue, students read, displayed, or performed excerpts from feminist manifestos that they authored in a feminist theory or women and gender studies course at The College at Brockport. The manifesto assignment asked students to select a contemporary feminist issue, and using text or text with performance, expose and analyze the issue drawing from “The Combahee River Collective” joined with “Trans *: A Quick and Quirky Account of Gender Variability.”” Prompted by the 6th Biennial SFD theme, “Race and Intersecting Feminist Futures, “we selected the Combahee River Collective and Trans * as our main theoretical frame because of ways these writings disrupt white heteronormativity and ways that they integrate an intersectional lens as means to critique gender and racial inequalities

Adventure in the Age of COVID-19: Embracing Microadventures and Locavism in a Post-Pandemic World

Unprecedented mobility restrictions due to COVID-19 have frozen the adventure travel and tourism industry. These restrictions have forced many to embrace ‘hyperlocal’ approaches to adventure and provided an opportunity to reimagine our adventure travel philosophies and practices. Despite claims that traditional adventure travel could address some of the “world’s most pressing challenges”, it has largely failed to realize its potential to provide a range of social, economic, and environmental benefits. Conversely, microadventure, which espouses adventures in nearby nature that are low-carbon and human-scaled, is an enticing alternative for both current and post-pandemic conditions. This essay first critiques pre-pandemic adventure travel and describes the hazards of this approach in age of COVID-19. It then explores creative ‘lockdown’ microadventures; envisions what post-pandemic adventure may look like; and explains why we not only need to embrace microadventures in a post-pandemic world, but also why we may prefer them to traditional adventure travel. Published in the Leisure Science Special Issue: Leisure in the Time of COVID-19, a Rapid Response

The Effect of Gibberellin on Millett

We are testing the effects of gibberellic acid on millet plants to determine if the mutation that caused them to be dwarf plants are gibberellin deficient or if the gibberellin response system is affected. In order to determine this, we will apply gibberellin solution to the millet plants and observe their growth or lack of growth. The dwarf mutant millet plants that are gibberellin would show growth like those with no mutation, and the millet plants that have a mutation in the gibberellin response system would not demonstrate any growth since they would be unable to process the gibberellin. The plants are measured weekly, and the data will determine the significance on the gibberellin application

Effect of improved atmospheric opacities in modelling sub-Neptunes

Aims. We investigate the impact of updated atmospheric mean opacity input values on modelled transit radius and the distribution of interior layer mass fractions. Methods. We developed and applied a coupled interior-atmosphere model. Our straightforward semi-grey calculation of atmospheric temperature enables us to perform thousands of model realisations in a Monte Carlo approach to address potential degeneracies in interior and atmospheric mass fraction. Our main constraints are planetary mass and radius from which our model infers distributions of the internal structure of exoplanetary classes ranging from Super-Earth to Mini-Neptune. We varied the relative masses of gas, envelope, mantle, and core layers subject to constraints on the bulk density from observations, and investigated the effect of updating atmospheric mean opacities. Results. First, we validate our model output with observed temperature profiles for modern Neptune. We can reproduce the basic features in the middle atmosphere but not the temperature inversion in the upper layers, which is likely because our model lacks aerosol heating. Calculated interiors are generally consistent with modern Neptune. Second, we compare with the well-studied object GJ 1214 b and obtain results that are broadly consistent with previous findings; they suggest correlations between modelled gas, water, and core mass fractions, although these are generally weak. Updating the opacities leads to a change on the order of a few percent in the modelled transit radius. This is comparable in magnitude to the planned accuracy of the PLATO data for planetary radius, suggesting that the opacity update in the model is important to implement

Machine learning inference of the interior structure of low-mass exoplanets

We explore the application of machine learning based on mixture density neural networks (MDNs) to the interior characterization of low-mass exoplanets up to 25 Earth masses constrained by mass, radius, and fluid Love number $k_2$. We create a dataset of 900$\:$000 synthetic planets, consisting of an iron-rich core, a silicate mantle, a high-pressure ice shell, and a gaseous H/He envelope, to train a MDN using planetary mass and radius as inputs to the network. For this layered structure, we show that the MDN is able to infer the distribution of possible thicknesses of each planetary layer from mass and radius of the planet. This approach obviates the time-consuming task of calculating such distributions with a dedicated set of forward models for each individual planet. While gas-rich planets may be characterized by compositional gradients rather than distinct layers, the method presented here can be easily extended to any interior structure model. The fluid Love number $k_2$ bears constraints on the mass distribution in the planets' interior and will be measured for an increasing number of exoplanets in the future. Adding $k_2$as an input to the MDN significantly decreases the degeneracy of the possible interior structures.Comment: 14 pages, 7 figures, accepted for publication in Ap

Abundance of water oceans on high-density exoplanets from coupled interior-atmosphere modeling

Liquid water is generally assumed to be the an essential factor for the emergence of life, and so a major goal in exoplanet science is the search for planets with water oceans. On terrestrial planets, the silicate mantle is a large source of water, which can be outgassed into the atmosphere via volcanism. Outgassing is subject to a series of feedback processes between atmosphere and interior, which continually shape both atmospheric composition, pressure, and temperature, as well as interior dynamics [1,2]. We present the results of an extensive parameter study, where we use a newly developed 1D numerical model to simulate the coupled evolution of the atmosphere and interior of terrestrial exoplanets up to 5 Earth masses around Sun-like stars, with internal structures ranging from Moon-to Mercury-like. The model accounts for the main mechanisms controlling the global-scale, long-term evolution of stagnant-lid rocky planets (i.e. bodies without plate tectonics), and it includes a large number of atmosphere-interior feedback processes, such as a CO2 weathering cycle, volcanic outgassing, a water cycle between ocean and atmosphere, greenhouse heating, as well as the influence of a potential primordial H2 atmosphere, which can be lost through escape processes.We find that a significant majority of high-density exoplanets(i.e. Mercury-like planets with large metallic cores) are able to outgas and sustain water on their surface. In contrast, most planets with intermediate, Earth-like densities either transition into a runaway greenhouse regime due to strong CO2 outgassing,or retain part of their primordial atmosphere, which prevents water from being outgassed. This suggests that high-density planets could be the most promising targets when searching for suitable candidates for hosting liquid water. [1] Tosi, N. et al. The habitability of a stagnant-lid earth. A&A605, A71 (2017). [2] Noack, L., Rivoldini, A. & Van Hoolst, T. Volcanism and outgassing of stagnant-lid planets: Implications for the habitable zone. Physics of the Earth and Planetary Interiors 269, 40-57 (2017)

Water oceans on high-density, stagnant-lid exoplanets from coupled interior-atmosphere modeling

Liquid water is generally assumed to be the most important factor for the emergence of life, and so a major goal in exoplanet science is the search for planets with water oceans. On terrestrial planets, the silicate mantle is a large source of water, which can be outgassed into the atmosphere via volcanism. Outgassing is subject to a series of feedback processes between atmosphere and interior, which continually shape both atmospheric composition, pressure, and temperature, as well as interior dynamics. We present the results of an extensive parameter study, where we use a newly developed 1D numerical model to simulate the coupled evolution of the atmosphere and interior of terrestrial exoplanets up to 5 Earth masses around Sun-like stars, with internal structures ranging from Moon- to Mercury-like. The model accounts for the main mechanisms controlling the global-scale, long-term evolution of stagnant-lid rocky planets (i.e. bodies without plate tectonics), and it includes a large number of atmosphere-interior feedback processes, such as a CO2 weathering cycle, volcanic outgassing, a water cycle between ocean and atmosphere, greenhouse heating, as well as the influence of a potential primordial H2 atmosphere, which can be lost through escape processes. We find that a significant majority of high-density exoplanets (i.e. Mercury-like planets with large cores) are able to outgas and sustain water on their surface. In contrast, most planets with intermediate, Earth-like densities either transition into a runaway greenhouse regime due to strong CO2 outgassing, or retain part of their primordial atmosphere, which prevents water from being outgassed. This suggests that high-density planets could be the most promising targets when searching for suitable candidates for hosting liquid water

Water oceans on high-density exoplanets from coupled interior-atmosphere modeling

Liquid water is generally assumed to be the most important factor for the emergence of life, and so a major goal in exoplanet science is the search for planets with water oceans. On terrestrial planets, the silicate mantle is a large source of water, which can be outgassed into the atmosphere via volcanism. Outgassing is subject to a series of feedback processes between atmosphere and interior, which continually shape both atmospheric composition, pressure, and temperature, as well as interior dynamics. We present the results of an extensive parameter study, where we use a newly developed 1D numerical model to simulate the coupled evolution of the atmosphere and interior of terrestrial exoplanets up to 5 Earth masses around Sun-like stars, with internal structures ranging from Moon- to Mercury-like. The model accounts for the main mechanisms controlling the global-scale, long-term evolution of stagnant-lid rocky planets (i.e. bodies without plate tectonics), and it includes a large number of atmosphere-interior feedback processes, such as a CO2 weathering cycle, volcanic outgassing, a water cycle between ocean and atmosphere, greenhouse heating, as well as the influence of a potential primordial H2 atmosphere, which can be lost through escape processes. We find that a significant majority of high-density exoplanets (i.e. Mercury-like planets with large cores) are able to outgas and sustain water on their surface. In contrast, most planets with intermediate, Earth-like densities either transition into a runaway greenhouse regime due to strong CO2 outgassing, or retain part of their primordial atmosphere, which prevents water from being outgassed. This suggests that high-density planets could be the most promising targets when searching for suitable candidates for hosting liquid water

Redox state and interior structure control on the long-term habitability of stagnant-lid planets

A major goal in exoplanet science is the search for planets with the right conditions to support liquid water (1). The habitability of a planet depends strongly on the composition of its atmosphere. Meanwhile, the interior and atmosphere of rocky planets are intricately linked through feedback processes and consequently evolve as a coupled system. In particular, volcanic outgassing of volatile species from the planet's silicate mantle shapes the atmospheric composition, temperature, and pressure, but the exact composition of outgassed species not only depends on the volatile content and redox state of the mantle, but also on the current state of the atmosphere (2, 3). This means that the interior dynamics of planets can not be neglected, especially since much of the surface water on terrestrial planets originates from the planetary mantle. In an extensive parameter study of rocky exoplanets, we investigated the emergence of habitable surface conditions for a wide range of initial conditions, including the planet mass, interior structure, volatile content and redox state, as well as the distance of the planet to its host star. The model accounts for the main mechanisms controlling the global-scale, long-term evolution of stagnant-lid rocky planets (i.e. bodies without plate tectonics), and it includes a large number of atmosphere-interior feedback processes, such as a CO2 weathering cycle, volcanic outgassing, a water cycle between ocean and atmosphere, greenhouse heating, as well as escape processes of H2. We find that only a narrow range of the mantle redox state around the iron-wüstite buffer allows forming atmospheres that lead to long-term habitable conditions. At more oxidizing conditions, most planets instead end up in a runaway greenhouse state (akin to Venus) due to strong CO2 outgassing. On the other hand, on planets with more reducing mantles, the amount of outgassed greenhouse gasses is often too low to keep the surface above the freezing point of water. References: (1) Noack, L., Snellen, I. & Rauer, H. Water in Extrasolar Planets and Implications for Habitability. Space Sci Rev 212, 877-898 (2017). (2) Ortenzi, G. et al. Mantle redox state drives outgassing chemistry and atmospheric composition of rocky planets. Sci Rep 10, 10907 (2020). (3) Gaillard, F. & Scaillet, B. A theoretical framework for volcanic degassing chemistry in a comparative planetology perspective and implications for planetary atmospheres. Earth and Planetary Science Letters 403, 307-316 (2014)