Search Publications
The Diffusion Tensor of Protons at 1 au: Comparing Simulation, Observation, and Theory
Engelbrecht, N. E.; Strauss, R. D.; Lang, J. T. +1 more
The natural variation in plasma parameters observed at 1 au can lead to a variation in transport parameters, such as diffusion and drift coefficients, for energetic charged particles of solar and galactic origin. Given the importance of these parameters to particle transport studies, this variation is investigated through test particle simulations…
Helioseismic Properties of Dynamo Waves in the Variation of Solar Differential Rotation
Kosovichev, Alexander G.; Mandal, Krishnendu; Pipin, Valery V.
Solar differential rotation exhibits a prominent feature: its cyclic variations over the solar cycle, referred to as zonal flows or torsional oscillations, are observed throughout the convection zone. Given the challenge of measuring magnetic fields in subsurface layers, understanding deep torsional oscillations becomes pivotal in deciphering the …
On the Possible Mechanisms of the SEP Event and Electron Enhancement over the SEP Decay Phase on 2023 August 5
Gan, W. Q.; Li, Y. P.; Firoz, Kazi A.
We carry out this study on the solar energetic particle (SEP) event that occurred on 2023 August 5 over the ascending phase of the current solar cycle 25. It is found that the SEP event might have been initiated by the M1.6 flare, while the SEP peak was caused by the coronal shock manifested in DH-type II radio burst over the propagation phase of …
An In-depth Analysis of Quiet-Sun IRIS Brightenings
Morgan, Huw; Humphries, Llŷr Dafydd; Kuridze, David
Small-scale brightenings are ubiquitous, dynamic, and energetic phenomena found in the chromosphere. An advanced filter-detection algorithm applied to high-resolution observations from the Interface Region Imaging Spectrograph enables the detection of these brightenings close to the noise level. This algorithm also tracks the movement of these bri…
Zone of Preferential Heating for Minor Ions in the Solar Wind
Klein, Kristopher G.; Kasper, Justin; Lepri, Susan T. +2 more
The properties of minor ions in the solar wind are important indicators of the state of the solar corona and the heating processes it undergoes as it expands. Evidence of preferential heating of minor ions has been observed in the solar wind, and is believed to be active up to a certain radial boundary, beyond which thermalization due to Coulomb c…
Reevaluating the Origin of Detectable Cataclysmic Variables in Globular Clusters: Testing the Importance of Dynamics
Belloni, Diogo; Rivera Sandoval, Liliana; Ramos Arevalo, Miriam
Based on the current detectable cataclysmic variable (CV) population in Galactic globular clusters (GCs), we show that there is not a clear relation between the number of sources per unit of mass and the stellar encounter rate, the cluster mass, or the cluster central density. If any, only in the case of core-collapsed GCs could there be an antico…
Phase-dependent Spectral Shape Changes in the Ultraluminous X-Ray Pulsar NGC 5907 ULX1
Yamaguchi, Hiroya; Kobayashi, Shogo B.; Miura, Daiki
The discovery of coherent pulsations from several ultraluminous X-ray pulsars (ULXPs) has provided direct evidence of a supercritical accretion flow. However, the geometrical structure of such an accretion flow onto the central neutron star remains poorly understood. NGC 5907 ULX1 is one of the most luminous ULXPs, with a luminosity exceeding 10
Absolute Dimensions of the Interferometric Binary HD 174881: A Test of Stellar Evolution Models for Evolved Stars
Torres, Guillermo; Monnier, John D.; van Belle, Gerard T. +1 more
We report high-resolution spectroscopic monitoring and long-baseline interferometric observations with the Palomar Testbed Interferometer (PTI) of the 215 day binary system HD 174881 (K1 II-III), composed of two giant stars. The system is spatially resolved with the PTI, as well as in archival measurements with the CHARA Array. Our analysis of the…
The Magnetic Field in Quiescent Star-forming Filament G16.96+0.27
Pattle, Kate; Sanhueza, Patricio; Kwon, Woojin +20 more
We present 850 µm thermal dust polarization observations with a resolution of 14.″4 (∼0.13 pc) toward an infrared dark cloud G16.96+0.27 using James Clerk Maxwell Telescope/POL-2. The average magnetic field orientation, which roughly agrees with the larger-scale magnetic field orientation traced by the Planck 353 GHz data, is approximately p…
A Model of the C IV λ λ1548, 1550 Doublet Line in T Tauri Stars
France, Kevin; Calvet, Nuria; Espaillat, Catherine C. +7 more
The C IV doublet in the UV has long been associated with accretion in T Tauri stars. However, it is still unclear where and how the lines are formed. Here, we present a new C IV line model based on the currently available accretion shock and accretion flow models. We assume axisymmetric, dipolar accretion flows with different energy fluxes and cal…