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Estimating Ion Temperatures at the Polar Coronal Hole Boundary
Landi, Enrico; Zhu, Yingjie; Szente, Judit
The temperatures of the heavy ions (T i ) in the solar corona provide critical information about the heating mechanism of the million-degree corona. However, the measurement of T i is usually challenging due to the nonthermal motion, instrumental limitations, and optically thin nature of the coronal emissions. We present t…
Orbital parallax of binary systems compared to Gaia DR3 and the parallax zero-point offset at bright magnitudes
Groenewegen, M. A. T.
Multiple systems for which the astrometric and spectroscopic orbit are known offer the unique possibility of determining the distance to these systems directly without any assumptions. They are therefore ideal objects for a comparison of Gaia data release 3 (GDR3) parallax data, especially since GDR3 presents the results of the non-single star (NS…
CSS1603+19: a low-mass polar near the cataclysmic variable period minimum
Thorstensen, John R.; Zakamska, Nadia L.; Hwang, Hsiang-Chih +1 more
CSS1603+19 is a cataclysmic variable (CV) with an orbital period of 81.96 min, near the minimal period of CVs. It is unusual in having a strong mid-infrared excess inconsistent with thermal emission from a brown dwarf companion. Here, we present time-resolved multiwavelength observations of this system. WISE photometry indicates that the mid-infra…
Probing general relativity in galactic scales at z 0.3
Chies-Santos, Ana L.; Furlanetto, Cristina; Melo-Carneiro, Carlos R.
General Relativity (GR) has been successfully tested mainly at Solar system scales; however, galaxy-scale tests have become popular in the last few decades. In this work, we investigate the ηPPN parameter, which is commonly defined by the ratio of two scalar potentials that appears in the cosmological linearly perturbed metric. Under th…
A Review of Instrument Techniques to Measure Magnetospheric Cold Electrons and Ions
Reisenfeld, Daniel B.; Maldonado, Carlos A.; Resendiz Lira, Pedro A. +3 more
A review of the instruments and techniques to directly measure the full distributions of the cold-ion and cold-electron populations in the magnetosphere is presented. Relatively few studies have focused on the cold plasma populations of the magnetosphere due to difficulties associated with obtaining measurements. The cold particle populations are …
Permafrost molards as an analogue for ejecta-ice interactions at Hale Crater, Mars
Lucas, Antoine; Conway, Susan; Noblet, Axel +7 more
When the Hale impact crater penetrated the martian cryosphere 1Ga, landforms indicating post-impact volatile mobilisation were generated. We have found landforms in the ejecta blanket of Hale Crater similar to 'permafrost molards' found in periglacial environments on Earth, and probably related to the past or present presence of volatiles at/near …
Reddening-Free Q Parameters to Classify B-Type Stars with Emission Lines
Aidelman, Yael; Cidale, Lydia Sonia
The emission-line B-type stars constitute a heterogeneous group. Many of these stars show similar optical spectroscopic features and color indices, making it difficult to classify them adequately by means of photometric and spectroscopic techniques. Thus, it is relevant to deal with appropriate classification criteria to avoid as many selection ef…
Groundwater-Controlled Deposition of Equatorial Layered Deposits in Central Arabia Terra, Mars
Pondrelli, M.; Marinangeli, L.; Silvestro, S. +5 more
Equatorial Layered Deposits (ELDs) reveal aspects of past depositional environments useful for timing climatic and geological events on Mars. However, their formation has several contending hypotheses which reflect a diverse range of possible environments. To better constrain their formation mechanism, we analyzed the stratigraphic and mineralogic…
Martian Atmospheric Aerosols Composition and Distribution Retrievals During the First Martian Year of NOMAD/TGO Solar Occultation Measurements: 1. Methodology and Application to the MY 34 Global Dust Storm
Modak, Ashimananda; Brines, Adrian; Stolzenbach, Aurélien +17 more
Since the beginning of the Trace Gas Orbiter (TGO) science operations in April 2018, its instrument "Nadir and Occultation for MArs Discovery" (NOMAD) supplies detailed observations of the IR spectrums of the Martian atmosphere. We developed a procedure that allows us to evaluate the composition and distribution's parameters of the atmospheric Mar…
Gas absorption towards the η Tel debris disc: winds or clouds?
Rebollido, Isabel; Panić, Olja; Iglesias, Daniela P.
η Telescopii is an ~23 Myr old A-type star surrounded by an edge-on debris disc hypothesized to harbour gas. Recent analysis of far- and near-ultraviolet spectroscopic observations of η Tel found absorption features at ~-23 and ~-18 km s-1 in several atomic lines, attributed to circumstellar and interstellar gas, respectively. In this w…