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Related papers: Solar transition region above sunspots

200 papers

Solar coronal plumes long seemed to possess a simple geometry supporting spatially coherent, stable outflow without significant fine structure. Recent high-resolution observations have challenged this picture by revealing numerous…

Solar and Stellar Astrophysics · Physics 2021-01-27 V. M. Uritsky , C. E. DeForest , J. T. Karpen , C. R. DeVore , P. Kumar , N. E. Raouafi , P. F. Wyper

Plumes are one of the most ubiquitous features seen at the limb in polar coronal holes and are considered to be a source of high density plasma streams to the fast solar wind. We analyze STEREO observations of plumes and aim to reinterpret…

Solar and Stellar Astrophysics · Physics 2010-08-31 Scott W. McIntosh , Davina E. Innes , Bart De Pontieu , Robert J. Leamon

Parker Solar Probe (PSP) counts dust impacts in the near-solar region, but modelling effort is needed to understand the dust population's properties. We aim to constrain the dust cloud's properties based on the flux observed by PSP. We…

Earth and Planetary Astrophysics · Physics 2024-12-04 Samuel Kočiščák , Audun Theodorsen , Ingrid Mann

Sunspot chromospheres display vigorous oscillatory signature when observed in chromospheric diagnostics like the strong Ca II lines and H-alpha. New high-resolution sunspot observations from the Swedish 1-m Solar Telescope show the…

Solar and Stellar Astrophysics · Physics 2015-06-16 Luc Rouppe van der Voort , Jaime de la Cruz Rodriguez

Polar brightening of the Sun at radio frequencies has been studied for almost fifty years and yet a disagreement persists between solar atmospheric models and observations. Some observations reported brightening values much smaller than the…

During the New Horizons spacecraft's encounter with Pluto, the Alice ultraviolet spectrograph conducted a series of observations that detected emissions from both the interplanetary medium (IPM) and Pluto. In the direction of Pluto, the IPM…

Blend lines form an integral part of the theoretical analysis and modeling of the polarized spectrum of the Sun. Their interaction with other spectral lines needs to be explored and understood before we can properly use the main spectral…

Solar and Stellar Astrophysics · Physics 2015-12-25 K. Sowmya , K. N. Nagendra , M. Sampoorna

We use a sample of 4178 Lyman break galaxies (LBGs) at z = 3, 4 and 5 in the UKIRT Infrared Deep Sky Survey (UKIDSS) Ultra Deep Survey (UDS) field to investigate the relationship between the observed slope of the stellar continuum emission…

We report on the physical properties of small-scale transient flows observed simultaneously at high cadence with the SUMER spectrometer and the TRACE imager in the plage area of an active region. Our major objective is to provide a better…

Astrophysics · Physics 2009-11-13 M. S. Madjarska , J. G. Doyle

Some studies suggest that the dust temperatures ($T_\mathrm{d}$) in high-redshift ($z\gtrsim 5$) Lyman break galaxies (LBGs) are high. However, possible observational bias in $T_\mathrm{d}$ is yet to be understood. Thus, we perform a simple…

Astrophysics of Galaxies · Physics 2021-11-17 Yung Ying Chen , Hiroyuki Hirashita , Wei-Hao Wang , Naomasa Nakai

Context. The bright heads of penumbral filaments, penumbral grains (PGs), are manifestations of hot plasma flows rising to the surface. They are observed to move horizontally toward the sunspot umbra or away from it. Recent analyses of…

Solar and Stellar Astrophysics · Physics 2025-07-09 Michal Sobotka , Markus Schmassmann

During solar flares, spectral lines formed in the photosphere have been shown to exhibit changes to their profiles despite the challenges of energy transfer to these depths. Recent work has shown that deep-forming spectral lines are subject…

Solar and Stellar Astrophysics · Physics 2024-01-05 Aaron J. Monson , Mihalis Mathioudakis , Adam F. Kowalski

It is well-known that the global acoustic oscillations of the Sun's atmosphere can excite resonance modes within large-scale magnetic concentrations. These structures are conduits of energy between the different layers of the solar…

Solar and Stellar Astrophysics · Physics 2025-05-14 M. Berretti , M. Stangalini , G. Verth , V. Fedun , S. Jafarzadeh , D. B. Jess , F. Berrilli

Context. The Evershed effect, a nearly horizontal outflow of material seen in the penumbrae of sunspots in the photospheric layers, is a common characteristic of well-developed penumbrae, but is still not well understood. Even less is known…

Solar and Stellar Astrophysics · Physics 2017-11-08 A. Siu-Tapia , A. Lagg , S. K. Solanki , M. van Noort , J. Jurčák

This work reports a peculiar and interesting train of microwave type III pair bursts in the impulsive rising phase of a solar flare on 2011 September 26. The observations include radio spectrometers at frequency of 0.80 - 2.00 GHz, hard…

Solar and Stellar Astrophysics · Physics 2016-09-28 Baolin Tan , Marian Karlicky , Hana Meszarosova , Larisa Kashapova , Jing Huang , Yan Yan , Eduard P. Kontar

We investigate the Lyman alpha line transfer in nearby and high redshift starbursting galaxies, where the effect of high optical depths and the role of dust in the scattering medium are expected to be conspicuous and should be treated in a…

Astrophysics · Physics 2009-10-31 Sang-Hyeon Ahn , Hee-Won Lee , Hyung Mok Lee

The Prominence-Corona Transition Region (PCTR) plays a key role in the thermal and pressure equilibrium of solar prominences. Our knowledge of this interface is limited and several major issues remain open, including the thermal structure…

Solar and Stellar Astrophysics · Physics 2015-06-05 Susanna Parenti , Brigitte Schmieder , Petr Heinzel , Leon Golub

Context. Fully fledged penumbrae have been widely studied both observationally and theoretically. Yet the relatively fast process of penumbra formation has not been studied closely with high spatial resolution. Aims. We investigate the…

Solar and Stellar Astrophysics · Physics 2024-06-05 M. García-Rivas , J. Jurčák , N. Bello González , J. M. Borrero , R. Schlichenmaier , P. Lindner

The decay of sunspot plays a key role in magnetic flux transportation in solar active regions (ARs). To better understand the physical mechanism of the entire decay process of a sunspot, an {\alpha}-configuration sunspot in AR NOAA 12411…

Solar and Stellar Astrophysics · Physics 2024-01-12 Yang Peng , Zhi-Ke Xue , Xiao-Li Yan , Aimee A. Norton , Zhong-Quan Qu , Jin-Cheng Wang , Zhe Xu , Li-Heng Yang , Qiao-Ling Li , Li-Ping Yang , Xia Sun

We propose and employ a novel empirical method for determining chromospheric plage regions, which seems to better isolate plage from its surrounding regions compared to other methods commonly used. We caution that isolating plage from its…