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Evolution of anisotropic turbulence in the fast and slow solar wind: Theory and Solar Orbiter measurements
Fedorov, A.; Horbury, T. S.; Louarn, P. +8 more
Aims: Solar Orbiter (SolO) was launched on February 9, 2020, allowing us to study the nature of turbulence in the inner heliopshere. We investigate the evolution of anisotropic turbulence in the fast and slow solar wind in the inner heliosphere using the nearly incompressible magnetohydrodynamic (NI MHD) turbulence model and SolO measurements…
Parker Solar Probe observations of He/H abundance variations in SEP events inside 0.5 au
Mitchell, D. G.; McComas, D. J.; Bale, S. D. +24 more
Aims: The Parker Solar Probe (PSP) orbit provides an opportunity to study the inner heliosphere at distances closer to the Sun than previously possible. Due to the solar minimum conditions, the initial orbits of PSP yielded only a few solar energetic particle (SEP) events for study. Recently during the fifth orbit, at distances from 0.45 to 0…
The distribution of open clusters in the Galaxy
Monteiro, Hektor; Barros, Douglas A.; Lépine, Jacques R. D. +1 more
In this work we explore the new catalog of galactic open clusters that became available recently, containing 1750 clusters that have been re-analysed using the Gaia DR2 catalog to determine the stellar memberships. We used the young open clusters as tracers of spiral arms and determined the spiral pattern rotation speed of the Galaxy and the corot…
Characteristics of the Basal Interface of the Martian South Polar Layered Deposits
Plaut, Jeffrey J.; Khuller, Aditya R.
We expand on previous studies of the South Polar Layered Deposits' (SPLD) basal interface using data acquired by the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) to obtain detailed maps of elevation, topography, and reflected radar power. Using these maps, we derive the thickness (ranging from 0 to 3.7 km) and volume of the…
The Wolf-Rayet + Black Hole Binary NGC 300 X-1: What is the Mass of the Black Hole?
Williams, Benjamin F.; Eracleous, Michael; Plucinsky, Paul P. +6 more
We present new X-ray and UV observations of the Wolf-Rayet + black hole (BH) binary system NGC 300 X-1 with the Chandra X-ray Observatory and the Hubble Space Telescope Cosmic Origins Spectrograph. When combined with archival X-ray observations, our X-ray and UV observations sample the entire binary orbit, providing clues to the system geometry an…
Interactions between large-scale radio structures and gas in a sample of optically selected type 2 quasars
Humphrey, A.; Storchi-Bergmann, T.; Bellocchi, E. +5 more
Context. The role of radio mode feedback in non radio-loud quasars needs to be explored in depth to determine its true importance. Its effects can be identified based on the evidence of interactions between the radio structures and the ambient ionised gas.
Aims: We investigate this interaction in a sample of 13 optically selected type 2 quasa…
Speckle Interferometry at SOAR in 2020
Henry, Todd J.; Tokovinin, Andrei; Mann, Andrew W. +3 more
The results of speckle interferometric observations at the 4.1 m Southern Astrophysical Research Telescope in 2020, as well as earlier unpublished data, are given, totaling 1735 measurements of 1288 resolved pairs and nonresolutions of 1177 targets. We resolved for the first time 59 new pairs or subsystems in known binaries, mostly among nearby dw…
Optical and Near-infrared Pulsation Properties of RR Lyrae and Population II Cepheid Variables in the Messier 15 Globular Cluster
Marconi, Marcella; Rejkuba, Marina; Yang, Soung-Chul +2 more
Messier 15 (NGC 7078) is an old and metal-poor post core-collapse globular cluster that hosts a rich population of variable stars. We report new optical (gi) and near-infrared (NIR, JKs) multi-epoch observations for 129 RR Lyrae, 4 Population II Cepheids (3 BL Herculis, 1 W Virginis), and 1 anomalous Cepheid variable candidate in M15 ob…
Solar wind current sheets and deHoffmann-Teller analysis. First results from Solar Orbiter's DC electric field measurements
André, N.; Fedorov, A.; Lavraud, B. +25 more
Context. Solar Orbiter was launched on 10 February 2020 with the purpose of investigating solar and heliospheric physics using a payload of instruments designed for both remote and in situ studies. Similar to the recently launched Parker Solar Probe, and unlike earlier missions, Solar Orbiter carries instruments designed to measure low-frequency D…
Could the Local Cavity be an Irregularly Shaped Strömgren Sphere?
Redfield, Seth; Linsky, Jeffrey L.
Extending for 50-200 pc in all directions from the Sun, the Local Cavity has been characterized as an old supernova bubble consisting of low-density million-degree plasma heated by supernova shocks. We summarize the arguments for and against this model and conclude that hydrogen in the Local Cavity is fully ionized, and the plasma near the Galacti…