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The existence of hot X-ray onsets in solar flares
Krucker, Säm; Veronig, Astrid M.; Dickson, Ewan C. M. +9 more
Context. It is well known among the scientific community that solar flare activity often begins well before the main impulsive energy release. However, a consistent explanation for this phenomenon has not yet been established.
Aims: Our aim is to investigate the earliest phase of four distinct flares observed by Solar Orbiter/STIX and determi…
Multi-campaign asteroseismic analysis of eight solar-like pulsating stars observed by the K2 mission
García, R. A.; Pérez Hernández, F.; Mathur, S. +11 more
The NASA K2 mission that succeeded the nominal Kepler mission observed several hundred thousand stars during its operations. While most of the stars were observed in single campaigns of ∼80 days, some of them were targeted for more than one campaign. We perform an asteroseismic study of a sample of eight solar-like stars observed during K2 Campaig…
Far-ultraviolet Spectroscopy of Active Galactic Nuclei with ASTROSAT/UVIT
Papadakis, I. E.; Singh, K. P.; Dewangan, G. C. +4 more
We study accretion disk emission from eight Seyfert 1-1.5 active galactic nuclei (AGN) using far-ultraviolet (FUV) (1300-1800 Å) slitless grating spectra acquired with AstroSat/UVIT. We correct for the Galactic and intrinsic extinction, contamination from the host galaxies, narrow and broad-line regions, Fe II emission, and Balmer continuum, and d…
Hazy with a Chance of Star Spots: Constraining the Atmosphere of Young Planet K2-33b
Vanderburg, Andrew; Mann, Andrew W.; Irwin, Jonathan M. +10 more
Although all-sky surveys have led to the discovery of dozens of young planets, little is known about their atmospheres. Here, we present multiwavelength transit data for the super-Neptune sized exoplanet, K2-33b-the youngest (~10 Myr) transiting exoplanet to date. We combined photometric observations of K2-33 covering a total of 33 transits spanni…
Spectroscopic Orbits of Subsystems in Multiple Stars. X (Summary)
Tokovinin, Andrei
Results of a large program of spectroscopic monitoring of nearby solar-type stellar hierarchical systems using the CHIRON echelle spectrograph at the 1.5 m telescope are summarized. Ten papers of this series contain 102 spectroscopic orbits and substantially contribute to the knowledge of periods and eccentricties, providing input for the study of…
Tilted discs in six poorly studied cataclysmic variables
Stefanov, Stefan Y.; Stefanov, Atanas K.
In this work, we search for negative superhumps (nSHs) in poorly studied cataclysmic variables using Transiting Exoplanet Survey Satellite data. We find three eclipsing binaries with nSH signatures: HBHA 4204-09, Gaia DR3 5931071148325476992, and SDSS J090113.51+144704.6. The last one exhibits IW And-like behaviour in archival Zwicky Transient Fac…
On the General Correlation between 3D Solar Wind Speed and Density Model and Solar Proxies
Bzowski, M.; Tokumaru, M.; Porowski, C.
The solar wind (SW) is a supersonic outflow of plasma from the solar corona, with the latitudinal speed and density profiles varying with the solar activity. The SW protons charge exchange with the inflowing interstellar neutral atoms and create energetic neutral atoms (ENAs), which bring information on the physical state of the plasma within the …
Unraveling the Complex Structure of AGN-driven Outflows. VI. Strong Ionized Outflows in Type 1 AGNs and the Outflow Size-Luminosity Relation
Luo, Rongxin; Chung, Aeree; Baek, Junhyun +4 more
We present spatially resolved gas kinematics, ionization, and energetics of 11 type 1 and 5 type 2 active galactic nuclei (AGNs) with strong ionized gas outflows at z <0.3 using Gemini Multi-Object Spectrograph Integral Field Unit data. We find a strongly blueshifted region in [O III] velocity maps, representing an approaching cone in biconical…
Occurrence rate of hot Jupiters orbiting red giant stars
Snellen, Ignas A. G.; Temmink, Milou
Context. Hot Jupiters form an enigmatic class of object whose formation pathways are not yet clear. Determining their occurrence rates as a function of orbit, planet and stellar mass, and system age can be an important ingredient for understanding how they form. To date, various hot Jupiters have been discovered orbiting red giant stars, and deriv…
Solar Electron Beam-Langmuir Wave Interactions and How They Modify Solar Electron Beam Spectra: Solar Orbiter Observations of a Match Made in the Heliosphere
Verscharen, Daniel; Maksimovic, Milan; Ryan, Daniel F. +7 more
Solar Orbiter's four in situ instruments have recorded numerous energetic electron events at heliocentric distances between 0.5 and 1 au. We analyze energetic electron fluxes, spectra, pitch-angle distributions, associated Langmuir waves, and type III solar radio bursts for three events to understand what causes modifications in the electron flux …