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AstroSat Investigation of X-ray Flares on Two Active K-M Systems: CC Eri and AB Dor
Karmakar, Subhajeet; Rawat, Nikita; Pandey, Jeewan Chandra +2 more
We present an X-ray and UV investigation of five X-ray flares detected on two active systems, CC Eri and AB Dor, using the AstroSat observatory. The peak X-ray luminosities of the flares in the 0.3–7.0 keV band are found to be within 1031‑33 erg s‑1. Preliminary spectral analysis indicates the presence of three and four-temperature corona for CC E…
Plasma diagnostics of supernova remnant 3C 400.2 by Suzaku observations
Nobukawa, Masayoshi; Uchiyama, Hideki; Nobukawa, Kumiko K. +2 more
We report on the results of plasma diagnostics of the supernova remnant (SNR) 3C 400.2, which has been reported to have a recombining plasma by previous studies. For careful background estimation, we simultaneously fitted spectra extracted from the SNR and background regions and evaluated the SNR emission contaminating the background-region spectr…
Formation of a Magnetic Cloud from the Merging of Two Successive Coronal Mass Ejections
Wang, Rui; Liu, Ying D.; Hu, Huidong +2 more
On 2022 March 28 two successive coronal mass ejections (CMEs) were observed by multiple spacecraft and resulted in a magnetic cloud (MC) at 1 au. We investigate the propagation and interaction properties of the two CMEs correlated with the MC using coordinated multipoint remote sensing and in situ observations from Solar Orbiter, STEREO-A, Solar a…
Tracing the Propagation of Shocks in the Equatorial Ring of SN 1987A over Decades with the Hubble Space Telescope
Fransson, Claes; Larsson, Josefin; Tegkelidis, Christos
The nearby SN 1987A offers a unique opportunity to investigate the complex shock interaction between the ejecta and circumstellar medium. We track the evolution of the optical hot spots within the equatorial ring (ER) by analyzing 33 Hubble Space Telescope imaging observations between 1994 and 2022. By fitting the ER with an elliptical model, we d…
X-Ray Emission of Nearby Low-mass and Sunlike Stars with Directly Imageable Habitable Zones
Peacock, Sarah; Kane, Stephen R.; Schwieterman, Edward W. +5 more
Stellar X-ray and UV radiation can significantly affect the survival, composition, and long-term evolution of the atmospheres of planets in or near their host star's habitable zone (HZ). Especially interesting are planetary systems in the solar neighborhood that may host temperate and potentially habitable surface conditions, which may be analyzed…
Classifying the clouds of Venus using unsupervised machine learning
Molaverdikhani, K.; Grassi, T.; Ercolano, B. +2 more
Because Venus is completely shrouded by clouds, they play an important role in the planet's atmospheric dynamics. Studying the various morphological features observed on satellite imagery of the Venusian clouds is crucial to understanding not only the dynamic atmospheric processes, but also interactions between the planet's surface structures and …
A Diamond Ring in X-Ray: Investigating the Diffuse Emission of Supernova Remnant G28.8+1.5
Zhang, Kaiyue
Supernova remnants are products of supernova explosions, which are usually observed in the X-ray band. However, the diffuse emission from the galactic supernova remnant G28.8+1.5 has been overlooked following initial searches for pulsars and pulsar wind nebulae. This paper presents background-subtracted imaging and spatial-resolved spectral analys…
Millisecond pulsars phenomenology under the light of graph theory
de Martino, D.; Torres, D. F.; Papitto, A. +4 more
We compute and apply the minimum spanning tree (MST) of the binary millisecond pulsar population, and discuss aspects of the known phenomenology of these systems in this context. We find that the MST effectively separates different classes of spider pulsars – eclipsing radio pulsars in tight binary systems with a companion of either ~0.1–0.8 M
Comparison of Direct Magnetic Field Measurements in a Sunspot by Ten Spectral Lines of Fe I, Fe II, Ti I, and Ti II
Lozitsky, V. G.; Lozitska, N. I.; Yakovkin, I. I. +1 more
Direct magnetic field measurements in sunspots by many spectral lines are important for elucidating the true magnitude and structure of the magnetic field at different levels of the solar atmosphere. Currently, magnetographic measurements are the most widespread, but such measurements mainly represent the longitudinal component of the magnetic fie…
Compact ellipticals in the Antlia cluster of galaxies
Richtler, Tom; Caso, Juan Pablo; Bassino, Lilia P. +3 more
Context. Compact ellipticals (cEs) are rare objects in the local Universe, but relevant for the evolution of galaxies. Their origin is not completely understood, with evidence equally suggesting that they are relics of early epochs, and remnants of tidal disruptions. Aims. This article aims to characterise two cEs, members of the nearby Antlia clu…