Search Results (3)

Assessing the habitability of exoplanets (planets orbiting other stars) is of great importance in deciding which planets warrant further careful study. Planets in the habitable zones of stars like our Sun are sufficiently far away from the star so that the light rays from the star can be assumed to be parallel, leading to straightforward analytic models for stellar illumination of the planet’s surface. However, for planets in the close-in habitable zones of dim red dwarf stars, such as the potentially habitable planet orbiting our nearest stellar neighbor, Proxima Centauri, the analytic illumination models based on the parallel ray approximation do not hold, resulting in severe biases in the estimates of the planetary characteristics, thus impacting efforts to understand the planet’s atmosphere and climate. In this paper, we present our efforts to improve the instellation (stellar illumination) models for close-in orbiting planets and the significance of the implementation of these improved models into EXONEST, which is a Bayesian machine learning application for exoplanet characterization. The ultimate goal is to use these improved models and parameter estimates to model the climates of close-in orbiting exoplanets using planetary General Circulation Models (GCM). More specifically, we are working to apply our instellation corrections to the NASA ROCKE-3D GCM to study the climates of the potentially habitable planets in the Trappist-1 system. Full article

Volcanism powered by tidal forces inside celestial bodies can provide enough energy to keep important solvents for living systems in the liquid phase. A prerequisite to calculate such tidal interactions and consequences is depending on simulations for tidal accelerations in a multi-body system. Unfortunately, from measurements in many extrasolar planetary systems, only few physical and orbital parameters are well-known enough for investigated celestial bodies. For calculating tidal acceleration vectors under missing most orbital parameter exactly, a simulation method is developed that is only based on a few basic parameters, easily measurable even in extrasolar planetary systems. Such a method as the one presented here allows finding a relation between the tidal acceleration vectors and potential heating inside celestial objects. Using the values and results of our model approach to our solar system as a “gold standard” for feasibility allowed us to classify this heating in relation to different forms of volcanism. This “gold standard” approach gave us a classification measure for the relevance of tidal heating in other extrasolar systems with a reduced availability of exact physical parameters. We help to estimate conditions for the identification of potential candidates for further sophisticated investigations by more complex established methods such as viscoelastic multi-body theories. As a first example, we applied the procedures developed here to the extrasolar planetary system TRAPPIST-1 as an example to check our working hypothesis. Full article

Drawing from long-term ethnographic research with a global network of contemplative Christians, this paper discusses an emerging teaching role for North American monasteries as the numbers of avowed religious decline. Since the Trappist community of St. Joseph’s Abbey in Spencer, Massachusetts, first developed the Christian meditation technique called Centering Prayer in the 1970s, monks and nuns have increasingly become teachers, models, and stabilizers of non-monastic practitioners who attempt to transform their ways of being and thinking towards monastic-inspired sensibilities. Their guidance includes the use of face-to-face, literary, and virtual means to teach methods of contemplative intersubjectivity and a commitment to lives based on service, hospitality, and humility, as well as on study and formalized rites. The paper focuses on non-monastics’ strong attraction to monastic teachings on ambiguity as a source of creativity and wonder in uncertain times, as practiced through a combination of cataphatic and apophatic ritual, including Centering Prayer. The number of monastic postulants continues to falter, yet a much larger, “non-gathered” community of non-monastic oblates and neo-monastic contemplatives has grown increasingly reliant on monastics to help provide alternatives. The rising interdependence of monastics and non-monastics may become the basis of a transformation of Christian monasticism and a new concept of religious community. Full article