Search Publications
Nonequilibrium Ionization Effects on Synthetic Spectra in the AWSoM Solar Corona
Landi, E.; van der Holst, B.; Szente, J.
In this work, we combined AWSoM's nonequilibrium ionization (NEI) calculations from Szente et al. with the synthetic spectral computations of SPECTRUM to predict nonequilibrium line intensities across the entire domain of the AWSoM 3D global model. We find that the resulting spectra are strongly affected by nonequilibrium effects in the fast-wind …
Can Clay Mimic the High Reflectivity of Briny Water Below the Martian SPLD?
Caprarelli, Graziella; Pettinelli, Elena; Cosciotti, Barbara +6 more
It has recently been suggested that clay minerals, which are widespread on the Martian surface, could be the possible source of the basal bright reflections detected by MARSIS at Ultimi Scopuli, instead of briny water. This hypothesis is based on dielectric measurements on a wet Ca-Montorillonite (STx-1b) sample conducted at 230 K, which reported …
Expulsion of Counter Evershed Flows from Sunspot Penumbrae
Solanki, S. K.; Korpi-Lagg, A.; Castellanos Durán, J. S.
In addition to the Evershed flow directed from the umbra toward the outer boundary of a sunspot, under special circumstances a counter Evershed flow (CEF) in the opposite direction also occurs. We aim to characterize the proper motions and evolution of three CEFs observed by the Solar Optical Telescope on board the Japanese Hinode spacecraft and t…
Deep eROSITA observations of the magnificent seven isolated neutron stars
Schwope, Axel; Mancini Pires, Adriana; Kurpas, Jan
We report the initial results of deep eROSITA monitoring of the magnificent seven isolated neutron stars (INSs). Thanks to a combination of high count statistics and good energy resolution, the eROSITA datasets unveil the increasingly complex energy distribution of these presumably simple thermal emitters. For three targets, we report the detectio…
Temporal Variations in Vertical Cloud Structure of Jupiter's Great Red Spot, Its Surroundings and Oval BA From HST/WFC3 Imaging
Irwin, Patrick G. J.; Sánchez-Lavega, Agustín.; Anguiano-Arteaga, Asier +2 more
In this study, we present the evolution of the properties and vertical distribution of the hazes in Jupiter's Great Red Spot (GRS), its surroundings and Oval BA from 2015 to 2021. To retrieve the main atmospheric parameters, we model the spectral reflectivity of a number of dynamically and/or spectrally interesting regions with a radiative transfe…
A candidate magnetic helium-core white dwarf in the globular cluster NGC 6397
Bahramian, Arash; Maccarone, Thomas J.; Althaus, Leandro G. +5 more
We report a peculiar variable blue star in the globular cluster (GC) NGC 6397, using Hubble Space Telescope optical imaging. Its position in the colour-magnitude diagrams and its spectrum are consistent with this star being a helium-core white dwarf (He WD) in a binary system. The optical light curve shows a periodicity at 18.5 h. We argue that th…
The 2175 Å interstellar extinction bump: is the wavelength variable?
Li, Aigen; Yang, X. J.; Wang, Qian
The most striking characteristics of the mysterious 2175$\mathring{\rm A}$ extinction bump, the strongest spectroscopic absorption feature seen on the interstellar extinction curve, are the invariant central wavelength and variable bandwidth: its peak position at 2175$\mathring{\rm A}$ is remarkably constant, while its bandwidth varies from one li…
When the Stars Align: A 5σ Concordance of Planetary Nebulae Major Axes in the Center of Our Galaxy
Parker, Quentin A.; Ritter, Andreas; Zijlstra, Albert A. +2 more
We report observations of a remarkable major axes alignment nearly parallel to the Galactic plane of 5σ significance for a subset of bulge "planetary nebulae" (PNe) that host, or are inferred to host, short-period binaries. Nearly all are bipolar. It is solely this specific PN population that accounts for the much weaker statistical alignments pre…
Direct evidence of substorm-related impulsive injections of electrons at Mercury
Barabash, Stas; Futaana, Yoshifumi; Persson, Moa +22 more
Mercury's magnetosphere is known to involve fundamental processes releasing particles and energy like at Earth due to the solar wind interaction. The resulting cycle is however much faster and involves acceleration, transport, loss, and recycling of plasma. Direct experimental evidence for the roles of electrons during this cycle is however missin…
Total electron content depression in the nightside Martian ionosphere: statistical results from Mars Express MARSIS measurements and implications
Rong, Zhaojin; Li, Lei; Wei, Yong +7 more
Thermal electron depression and energetic electron depletion are two well-known features of the nightside Martian ionosphere. While the latter has been extensively studied in the past, there is no report of systematic and firm identification of the former and hence the correlation between them is unknown. Applying an automatic procedure to the Mar…