Related papers: K-corona recording in the range < 1.4 Rsun

Detecting exoplanets and other faint sources of emitted and reflected light near a bright star requires deeply suppressing the starlight while efficiently transmitting the dim light from its surroundings. This suppression can be carried out…

The present work is an effort to investigate possible radial variations in the solar coronal rotation by analyzing the solar radio emission data at 15 different frequencies (275-1755 MHz) for the period starting from July 1994 to May 1999.…

We investigate the decayless regime of coronal kink oscillations recently discovered in the Solar Dynamics Observatory (SDO)/AIA data. In contrast to decaying kink oscillations that are excited by impulsive dynamical processes, this type of…

We employ a sequence of Doppler images obtained with the Coronal Multi-channel Polarimeter (CoMP) instrument to perform time-distance seismology of the solar corona. We construct the first k-omega diagrams of the region. These allow us to…

The quiescent or dynamic nature of fine scale ray-like features in the sun corona, observed in visible light, is still an open question. Here, we show that most of daily and hourly periodic variations in visible light brightness of the high…

Solar rotational tomography (SRT) applied to white-light coronal images observed at multiple aspect angles has been the preferred approach for determining the three-dimensional (3D) electron density structure of the solar corona. However,…

Direct imaging of exoplanets requires very high contrast levels, which are obtained using coronagraphs. But residual quasi-static aberrations create speckles in the focal plane downstream of the coronagraph which mask the planet. This…

Tomography of the solar corona can provide cruicial constraints for models of the low corona, unique information on changes in coronal structure and rotation rates, and a valuable boundary condition for models of the heliospheric solar…

The WFIRST-AFTA 2.4 m telescope will provide in the next decade the opportunity to host a coronagraph for the imaging and spectroscopy of planets and disks. The telescope, however, is not ideal, given its obscured aperture. Only recently…

Visible and near-infrared (V+NIR) emission lines were the first to be discovered in the corona, during total solar eclipses, and they continue to offer unique opportunities to study the physical properties of the corona. The most commonly…

The third flight of the High-Resolution Coronal Imager (Hi-C 2.1) occurred on May 29, 2018, the Sounding Rocket was launched from White Sands Missile Range in New Mexico. The instrument has been modified from its original configuration…

With the recent commissioning of ground instruments such as SPHERE or GPI and future space observatories like WFIRST-AFTA, coronagraphy should probably become the most efficient tool for identifying and characterizing extra-solar planets in…

Future high-contrast imaging spectroscopy with a large segmented telescope will be able to detect atmospheric molecules of Earth-like planets around G- or K-type main-sequence stars. Increasing the number of target planets will require a…

This paper gives a simple and original presentation of various coronagraphs inherited from the Lyot coronagraph. We first present the Lyot and Roddier phase mask coronagraphs and study their properties as a function of the focal mask size.…

The magnetic field in the Sun's corona stores energy that can be released to heat the coronal plasma and drive solar eruptions. Measurements of the global coronal magnetic field have been limited to a few snapshots. We present observations…

The most popular method for determining coronal temperatures is the scale-height-method (shm). It is based on electron density profiles inferred from White Light (WL) brightness measurements of the corona during solar eclipses. This method…

Three dimensional electron density distributions in the solar corona are reconstructed for 100 Carrington Rotations (CR 2054$-$2153) during 2007/03$-$2014/08 using the spherically symmetric method from polarized white-light observations…

Large coronal loops around one solar radius in altitude are an important connection between the solar wind and the low solar corona. However, their plasma properties are ill-defined as standard X-ray and UV techniques are not suited to…

Chandra has detected optically thin, thermal X-ray emission with a size of ~1 arcsec and luminosity ~10^33 erg/s from the direction of the Galactic supermassive black hole (SMBH), Sgr A*. We suggest that a significant or even dominant…

We developed a new technique for registration of the far solar corona from ground-based observations at distances comparable to those obtained from space coronagraphs. It makes possible visualization of fine details of studied objects…