Search Publications
CME Arrival Time Prediction Based on Coronagraph Observations and Machine-learning Techniques
Shen, Fang; Yang, Yi; Li, Yucong +2 more
The timely and precise prediction of the arrival time of coronal mass ejections (CMEs) is crucial in mitigating their potential adverse effects. In this study, we present a novel prediction method utilizing a deep-learning framework coupled with physical characteristics of CMEs and background solar wind. Time series images from synchronized solar …
Observation of solar energetic particles with Metis on board Solar Orbiter on February 25, 2023
Gissot, S.; Sasso, C.; Romoli, M. +29 more
Context. The Solar Orbiter Metis coronagraph captures images of the solar corona in both visible (VL) and ultraviolet (UV) light. Tracks ascribable to the passage of galactic and solar particles appear in the Metis images. An algorithm implemented in the Metis processing electronics allows us to separate the pixels fired by VL photons from those c…
Observation of Penumbra Downflows
Mozharovskii, S. G.
This paper describes penumbra supersonic downflows (PSDs), which can be observed using the Hinode spectropolarimeter. The map obtained from red wing wavelengths at the half of line depth of the Fe I λ 6302 Å line makes it easy to detect these flows. They represent visible fragments of penumbral filaments as they turn sharply before entering the de…
Determination of metallicities of red giant stars using machine learning techniques applied to the narrow and broadband photometry of the S-PLUS survey
Almeida-Fernandes, F.; Schoenell, W.; Daflon, S. +8 more
Aims. The aim of this study is to obtain metallicities of red giant stars from the Southern Photometric Local Universe Survey (S-PLUS) and to classify giant and dwarf stars using artificial neural networks applied to the S-PLUS photometry. Methods. We combined the five broadband and seven narrow-band filters of S-PLUS – especially centred on promi…
Black hole spin estimation of XTE J2012+381 using simultaneous observations of Swift/XRT and NuSTAR
Kumar, Raj
A sufficiently precise measurement of black hole spin is required to carry out quantitative tests of the Kerr metric and to understand several phenomena related to astrophysical black holes. After 24 yr, XTE J2012+381 again underwent an outburst in 2022 December. In this work, we focused on the measurement of the spin and mass of the black hole ca…
3C 273 host galaxy with Hubble Space Telescope coronagraphy
Debes, John H.; Perrin, Marshall D.; Ren, Bin B. +6 more
The close-in regions of bright quasars' host galaxies have been difficult to image due to the overwhelming light coming from quasars. With coronagraphic observations in visible light using the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope, we removed 3C 273 quasar light using color-matching reference stars. The observat…
An Informed and Systematic Method to Identify Variable Mid-L Dwarfs
Karalidi, Theodora; Manjavacas, Elena; Faherty, Jacqueline K. +3 more
Most brown dwarfs show some level of photometric or spectral variability. However, finding the most variable dwarfs more suited for a thorough variability monitoring campaign remained a challenge until a few years ago with the design of spectral indices to find the most likely L and T dwarfs using their near-infrared (NIR) single-epoch spectrum. I…
Galactic cosmic rays at 0.7 A.U. with Venus Express housekeeping data
Wood, Simon; Witasse, Olivier; Sánchez-Cano, Beatriz +5 more
We apply a previously developed procedure to characterize galactic cosmic rays (GCRs) at 0.7 A.U. with engineering data coming from the Venus Express mission. The engineering parameters are the Error Detection and Correction EDAC cumulative counters, used for detection and correction of memory errors induced by highly energetic particles. It has a…
The emerging archaeological record of Mars
Fairén, Alberto G.; Holcomb, Justin A.; O'Leary, Beth L. +2 more
Humans first reached Mars in 1971, initiating the record of human activity on the Red Planet. As planetary scientists plan for future planetary protection procedures for Mars, they should also consider the developing archaeological record on one of our nearest planets.
Modeling Global Magnetic-Flux Emergence in Bipolar Solar-Active Regions
Démoulin, Pascal; Mandrini, Cristina H.; López Fuentes, Marcelo +2 more
Active regions (ARs) appear in the solar atmosphere as a consequence of the emergence of magnetic-flux ropes (FR). In this study, we use Bayesian methods to analyze line-of-sight magnetograms of emerging ARs. We employ a FR model consisting of a half-torus field structure based on eight parameters. The goal is to derive constrained physical parame…