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Related papers: Bright fibrils in Ca II K

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The Interface Region Imaging Spectrograph (IRIS) reveals small-scale rapid brightenings in the form of bright grains all over coronal holes and the quiet sun. These bright grains are seen with the IRIS 1330 \AA, 1400 \AA\ and 2796 \AA\…

Solar pores are strongly magnetized regions lacking a photospheric penumbra and characterized by predominantly vertical magnetic fields. We present a multi-line study of flashes in a solar pore using high-resolution observations from the…

Solar and Stellar Astrophysics · Physics 2026-02-11 Sandeep Dubey , Christian Beck , Rahul Yadav , Tobias Felipe , Shibu K Mathew

Context. Fine-scale structures of the solar chromosphere, particularly fibrils, are known to host various types of magnetohydrodynamic (MHD) waves that can transport energy to the corona. In particular, absorption features observed in the…

Solar and Stellar Astrophysics · Physics 2025-05-01 E. Petrova , T. Van Doorsselaere , M. van Noort , D. Berghmans , J. S. Castellanos Durán

We study the polarization signals and physical parameters of penumbral microjets (PMJs) by using high spatial resolution data taken in the Fe I 630 nm pair, Ca II 854.2 nm and Ca II K lines with the CRISP and CHROMIS instruments at the…

Solar and Stellar Astrophysics · Physics 2019-01-16 S. Esteban Pozuelo , J. de la Cruz Rodriguez , A. Drews , L. Rouppe van der Voort , G. B. Scharmer , M. Carlsson

The Interface Region Imaging Spectrograph (IRIS) provides spectroscopy and narrow band slit-jaw (SJI) imaging of the solar chromosphere and transition region at unprecedented spatial and temporal resolution. Combined with high-resolution…

Solar and Stellar Astrophysics · Physics 2016-02-03 H. Skogsrud , L. Rouppe van der Voort , B. De Pontieu

Context: Solar pores are small sunspots lacking a penumbra that have a prevailing vertical magnetic field component. They can include light bridges at places with locally reduced magnetic field. Like sunspots, they exhibit a wide range of…

Solar and Stellar Astrophysics · Physics 2015-06-17 M. Sobotka , M. Švanda , J. Jurčák , P. Heinzel , D. Del Moro , F. Berrilli

The bulk of the radiative output of a solar flare is emitted from the chromosphere, which produces enhancements in the optical and UV continuum, and in many lines, both optically thick and thin. We have, until very recently, lacked…

Solar and Stellar Astrophysics · Physics 2015-10-07 Graham S. Kerr , Paulo J. A. Simões , Jiong Qiu , Lyndsay Fletcher

Numerical simulations of the solar chromosphere have become increasingly realistic over the past 5 years. However, many observed chromospheric structures and behavior are not reproduced. Current models do not show fibrils in Ca II 8542, and…

Solar and Stellar Astrophysics · Physics 2010-01-07 J. Leenaarts

We analysed state-of-the-art observations of the solar atmosphere to investigate the dependence of the \ca brightness of several solar features on spectral bandwidth and spatial resolution of the data. Specifically, we study data obtained…

Solar and Stellar Astrophysics · Physics 2023-04-20 M. Murabito , I. Ermolli , T. Chatzistergos , S. Jafarzadeh , F. Giorgi , L. Rouppe van der Voort

We study the properties of waves in a facular region of moderate strength in the photosphere and chromosphere. Our aim is to analyse statistically the wave periods, power and phase relations as a function of the magnetic field strength and…

Solar and Stellar Astrophysics · Physics 2015-06-17 Roman Kostik , Elena Khomenko

Flare ribbons are bright manifestations of flare energy dissipation in the lower solar atmosphere. For the first time, we report on high-resolution imaging spectroscopy observations of flare ribbons situated off-limb in the H$\beta$ and Ca…

Solar and Stellar Astrophysics · Physics 2020-07-01 D. Kuridze , M. Mathioudakis , P. Heinzel , J. Koza , H. Morgan , R. Oliver , A. F. Kowalski , J. C. Allred

Context. The wings of the Ca II H and K lines provide excellent photospheric temperature diagnostics. At the Swedish 1-meter Solar Telescope the blue wing of Ca II H is scanned with a narrowband interference filter mounted on a rotation…

Solar and Stellar Astrophysics · Physics 2012-12-18 V. M. J. Henriques

Searches for small exoplanets around solar-type stars are limited by stellar physical variability. While chromospheric variability is well studied, observing, modeling. and understanding the much smaller fluctuations in photospheric…

Solar and Stellar Astrophysics · Physics 2024-07-03 Dainis Dravins , Hans-Günter Ludwig

Aims. With the Solar Optical Telescope on Hinode, we investigate the basic properties of high-degree solar oscillations observed at two levels in the solar atmosphere, in the G-band (formed in the photosphere) and in the Ca II H line…

Astrophysics · Physics 2009-11-13 U. Mitra-Kraev , A. G. Kosovichev , T. Sekii

The O I 135.6 nm spectral line is formed in the chromosphere at the same heights as the Mg II h&k line cores are formed. As the O I line is optically thin, it represents a possibility for measuring the non-thermal velocities in this region…

Solar and Stellar Astrophysics · Physics 2026-05-05 Viggo Hansteen , Mats Carlsson , Bart De Pontieu , Daniel Nóbrega-Siverio

A cooperative observation with Hida observatory and Hinode satellite was performed on an emerging flux region. The successive Ca II K spectro-heliograms of the emerging flux region were taken by the Domeless Solar Telescope of Hida…

Recent dedicated Hinode polar region campaigns revealed the presence of concentrated kilogauss patches of magnetic field in the polar regions of the Sun which are also shown to be correlated with facular bright points at the photospheric…

Solar and Stellar Astrophysics · Physics 2019-04-17 Nancy Narang , Dipankar Banerjee , Kalugodu Chandrashekhar , Vaibhav Pant

Broad-band images in the Ca II H line, from the BFI instrument on the Hinode spacecraft, show emission from spicules emerging from and visible right down to the observed limb. Surprisingly, little absorption of spicule light is seen along…

Solar and Stellar Astrophysics · Physics 2015-05-18 Philip G. Judge , Mats Carlsson

We present the first high-resolution solar images in the Mg II k 2796 \AA{} line. The images, taken through a 4.8 \AA{} broad interference filter, were obtained during the second science flight of SUNRISE in June 2013 by the SuFI…

(Abridged) Aims: We characterize the dynamics of the quiet inter-network chromosphere by studying the occurrence of acoustic shocks and their relation with the concomitant photospheric structure and dynamics. Methods: We analyze a…

Astrophysics · Physics 2009-11-13 A. Vecchio , G. Cauzzi , K. P. Reardon