Context. Providing a detailed picture of the Sagittarius stream offers important constraints on the build-up of the Galactic halo as well as its gravitational potential at large radii. While several attempts have been made to model the structure of the Sagittarius stream, no model has yet been able to match all the features observed for the stream.
Context. Detailed shape modeling is a fundamental task in the context of small body exploration aimed at supporting scientific research and mission operations. The neural implicit method (NIM) is a novel deep learning technique that models the shapes of small bodies from multi-view optical images.
Using the Moon as a case study, we explore the effects of surface roughness at a small scale on the temperature of airless planetary bodies. Roughness can significantly influence temperature through a phenomenon known as ‘self-heating,’ in which indirect light plays a crucial role. Solar radiation can be locally reflected and scattered, causing this indirect light to reach areas of the surface that are typically not directly illuminated.
The quiet Sun corona and coronal holes, as seen in the extreme ultraviolet (EUV), host a variety of phenomena that operate over a range of spatial and temporal scales. Dynamic brightenings and jets of at most a few megameters appear to evolve on minute timescales. Coronal structures larger than tens of Mm evolve on much longer, hour timescales.
Context. As the most massive nodes of the cosmic web, galaxy clusters represent the best probes of structure formation. Over time, they grow by accreting and disrupting satellite galaxies, adding those stars to the brightest cluster galaxy (BCG) and the intra-cluster light (ICL). However, the formation pathways of galaxy clusters can vary significantly. Aims. To inform upcoming large surveys, we aim to identify observables that can distinguish galaxy cluster formation pathways. Methods.
This article describes condensation of the elements and use of condensation temperatures to plot and interpret Earth’s apparent volatility trend. Major points covered include the following. (1) Updated 50% condensation temperatures (T50) for all naturally occurring elements, Tc, and Pu are tabulated at 10−2 to 10−8 bar total pressure for solar composition material.
Aims. The objective of this work is to study the influence of a highly non-isothermal porous dust layer on the formation of a comet’s inner coma. We studied the water gas activity of comet 67P/Churyumov-Gerasimenko to find a link between the gas properties around the comet and the properties of the dust surface crust. The effects on the radiative transfer spectral lines were studied and compared with MIRO remote sensing observations. Methods.
Space Weather effects produced by Solar Energetic Particles (SEPs) present a direct radiation hazard to crew and spacecraft equipment, first in interplanetary space, and then, due to secondary effects, within the Earth’s magnetosphere and atmosphere. Being able to predict and/or forecast SEP events is of particular importance for the near-future planned manned missions to the Moon and Mars, as well as for our unimpeded daily living.
We report on a further analysis of the Airborne Infrared Spectrometer (AIR-Spec) observations from the 2019 July 2 total eclipse and present the identifications of three new coronal lines from Fe x, Si xi, and Si vi in AIR-Spec’s 1.87–1.99 μm band. The new lines were predicted to be observable but were not observed previously in the corona. The identifications are confirmed on the basis of observed and expected line wavelengths and radiances.
Jupiter’s auroral regions have previously been defined by broad‐scale auroral structures, but these are typically obscured by the wide array of temporal variability observed at timescales between minutes and days, making it difficult to understand the underlying magnetospheric biases driving these brightness differences.