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A new instrument was designed to take visible-light (VL) polarized brightness ($pB$) observations of the solar corona during the 14 December 2020 total solar eclipse. The instrument, called the Coronal Imaging Polarizer (CIP), consisted of…

Solar and Stellar Astrophysics · Physics 2023-10-16 Liam T. Edwards , Kaine A. Bunting , Brad Ramsey , Matthew Gunn , Tomos Fearn , Thomas Knight , Gabriel Domingo Muro , Huw Morgan

Context. In exoplanet searches with radial velocity data, the most common statistical significance metrics are the Bayes factor and the false alarm probability (FAP). Both have proved useful, but do not directly address whether an exoplanet…

Earth and Planetary Astrophysics · Physics 2022-07-06 Nathan C. Hara , Nicolas Unger , Jean-Baptiste Delisle , Rodrigo Díaz , Damien Ségransan

We investigate the thermal properties of a solar flare by the observations of soft X-ray Telescope (XRT) on board Hinode and the Atmospheric Image Assembly on board the Solar Dynamics Observatory (SDO/AIA). Our analysis reveals a tenuous…

Solar and Stellar Astrophysics · Physics 2025-10-22 Xiaoyan Xie , Anna Chen , Crisel Suarez , Katharine K. Reeves , Soumya Roy , Christopher S. Moore , Nishu Karna , Joy Velasquez

We present joint Hinode/EIS and IRIS observations of Fe XII lines in active regions, both on-disk and off-limb. We use an improved calibration for the EIS data, and find that the 192.4 A / 1349 A observed ratio is consistent with the values…

Solar and Stellar Astrophysics · Physics 2022-07-15 G. Del Zanna , V. Polito , J. Dudík , P. Testa , H. E. Mason , E. Dzifčáková

Waves are thought to play a significant role in the heating of the solar atmosphere and the acceleration of the wind. Among the many types of waves observed in the Sun, the so-called p-modes with a 3 mHz frequency peak dominate the lower…

In the present work we utilize ACE/SWICS in-situ measurements of the properties of the solar wind outside ICMEs in order to determine whether, and to what extent are the solar wind properties affected by the solar cycle. We focus on proton…

Solar and Stellar Astrophysics · Physics 2022-01-17 A. Cardenas-O'Toole , E. Landi

High resolution spectra from the Hinode EUV Imaging Spectrometer (EIS) have revealed that coronal spectral line profiles are sometimes asymmetric, with a faint enhancement in the blue wing on the order of 100 km/s. These asymmetries could…

Solar and Stellar Astrophysics · Physics 2015-06-11 David H. Brooks , Harry P. Warren

Negative ions have been detected in abundance in recent years by spacecraft across the solar system. These detections were, however, made by instruments not designed for this purpose and, as such, significant uncertainties remain regarding…

Space Physics · Physics 2021-06-17 Ravindra T. Desai , Zeqi Zhang , Xinni Wu , Charles Lue

We use 3D radiation magnetohydrodynamic models to investigate how the thermodynamic quantities in the simulation are encoded in observable quantities, thus exploring the diagnostic potential of the 133.5 nm lines. We find that the line core…

Solar and Stellar Astrophysics · Physics 2015-09-30 Bhavna Rathore , Mats Carlsson , Jorrit Leenaarts , Bart De Pontieu

Future missions such as Solar Orbiter (SO), InterHelioprobe, or Solar Probe aim at approaching the Sun closer than ever before, with on board some high resolution imagers (HRI) having a subsecond cadence and a pixel area of about $(80km)^2$…

Astrophysics · Physics 2015-05-13 Véronique Delouille , Pierre Chainais , Jean-François Hochedez

The temperatures of the heavy ions ($T_i$) in the solar corona provide critical information about the heating mechanism of the million-degree corona. However, the measurement of $T_i$ is usually challenging due to the nonthermal motion,…

Solar and Stellar Astrophysics · Physics 2023-05-17 Yingjie Zhu , Judit Szente , Enrico Landi

The formation of the transition-region O IV and Si IV lines observable by the Interface Region Imaging Spectrograph (IRIS) is investigated for both Maxwellian and non-Maxellian conditions characterized by a kappa-distribution exhibiting a…

Solar and Stellar Astrophysics · Physics 2015-06-18 Jaroslav Dudík , Giulio Del Zanna , Elena Dzifčáková , Helen E. Mason , Leon Golub

The determination of the cutoff frequency in real solar observations under different local physical conditions is an important and insufficiently explored aspect of waves in solar physics. This work utilizes the near ultraviolet (NUV)…

Solar and Stellar Astrophysics · Physics 2026-05-14 Pradeep Kayshap , Gayathri Hegde , Z. E. Musielak , Kris Murawski , Tobıas Felipe

The O I 135.56 nm line is covered by NASA's Interface Region Imaging Spectrograph (IRIS) small explorer mission which studies how the solar atmosphere is energized. We here study the formation and diagnostic potential of this line by means…

Solar and Stellar Astrophysics · Physics 2015-11-04 Hsiao-Hsuan Lin , Mats Carlsson

The accepted explanation of the observed dichotomy of two orders of magnitude between in situ measurements of electron density in HII regions, derived from emission line ratios, and average measurements based on integrated emission measure,…

Astrophysics · Physics 2016-08-16 C. Giammanco , J. E. Beckman , A. Zurita , M. Relaño

Solar filaments/prominences are one of the most common features in the corona, which may lead to energetic coronal mass ejections (CMEs) and flares when they erupt. Filaments are about one hundred times cooler and denser than the coronal…

Solar and Stellar Astrophysics · Physics 2017-02-22 Hongqiang Song , Yao Chen , Bo Li , Leping Li , Liang Zhao , Jiansen He , Die Duan , Xin Cheng , Jie Zhang

We present a detailed comparison between simulations and seeing-free observations that takes into account the crucial influence of instrumental image degradation. We use images of quiet Sun granulation taken in the blue, green and red…

Solar and Stellar Astrophysics · Physics 2015-05-13 Sven Wedemeyer-Böhm , Luc Rouppe van der Voort

3He-rich solar energetic particles (SEPs) are believed to be accelerated in solar flares or jets by a mechanism that depends on the ion charge-to-mass (Q/M) ratio. It implies that the flare plasma characteristics (e.g., temperature) may be…

Solar and Stellar Astrophysics · Physics 2021-03-10 R. Bucik , S. M. Mulay , G. M. Mason , N. V. Nitta , M. I. Desai , M. A. Dayeh

Solar jets are an important field of study, as they may contribute to the mass and energy transfer from the lower to the upper atmosphere. We use the Interface Region Imaging Spectrograph (IRIS) and Solar Dynamic Observatory (SDO)…

Solar and Stellar Astrophysics · Physics 2024-10-01 Myrto Koletti , Costis Gontikakis , Spiros Patsourakos , Kanaris Tsinganos

Extensions have been made recently to the coronal approximation for the purpose of modelling line emission from carbon and oxygen in the lower solar atmosphere. The same modelling is used here for other elements routinely observed in the…

Solar and Stellar Astrophysics · Physics 2021-06-30 R. P. Dufresne , G. Del Zanna , P. J. Storey