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Related papers: On the continuum intensity distribution of the sol…

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We have examined images from the Precision Solar Photometric Telescope (PSPT) at the Mauna Loa Solar Observatory (MLSO) in search of latitudinal variation in the solar photospheric intensity. Along with the expected brightening of the solar…

Astrophysics · Physics 2009-11-13 Mark P. Rast , Ada Ortiz , Randle W. Meisner

Context. Stellar spectral variability on timescales of a day and longer, arising from magnetic surface features such as dark spots and bright faculae, is an important noise source when characterising extra-solar planets. Current 1D models…

Solar and Stellar Astrophysics · Physics 2017-09-06 Charlotte M. Norris , Benjamin Beeck , Yvonne C. Unruh , Sami K. Solanki , Natalie A. Krivova , Kok Leng Yeo

Small-scale magnetic fields are major contributors to the solar irradiance variations. Hence, the continuum intensity contrast of magnetic elements in the quiet Sun (QS) network and in active region (AR) plage is an essential quantity that…

Solar and Stellar Astrophysics · Physics 2015-05-28 P. Kobel , S. K. Solanki , J. M. Borrero

Recently measured straylight PSFs in Hinode/SOT make granulation contrast in observed data and synthetic MHD data consistent. Data from earthbound telescopes also need accurate correction for straylight and fixed optical aberrations. We aim…

Instrumentation and Methods for Astrophysics · Physics 2012-01-16 M. G. Löfdahl , G. B. Scharmer

This study aims at setting observational constraints on the continuum and line core intensity contrast of network and faculae, specifically, their relationship with magnetic field and disc position. Full-disc magnetograms and intensity…

Solar and Stellar Astrophysics · Physics 2014-07-17 K. L. Yeo , S. K. Solanki , N. A. Krivova

Recent spectro-polarimetric observations have provided detailed measurements of magnetic field, velocity and intensity during events of magnetic field intensification in the solar photosphere. We consider the temporal evolution of the…

Solar and Stellar Astrophysics · Physics 2015-05-14 S. Danilovic , M. Schüssler , S. K. Solanki

While the velocity fluctuations of supergranulation dominate the spectrum of solar convection at the solar surface, very little is known about the fluctuations in other physical quantities like temperature or density at supergranulation…

Solar and Stellar Astrophysics · Physics 2016-12-07 J. Langfellner , A. C. Birch , L. Gizon

We aim to gain insight into the effect of network and faculae on solar irradiance from their apparent intensity. Taking full-disc observations from the Solar Dynamics Observatory, we examined the intensity contrast of network and faculae in…

Solar and Stellar Astrophysics · Physics 2021-02-19 K. L. Yeo , N. A. Krivova

Context. The contribution of quiet-Sun regions to the solar irradiance variability is currently unclear. Some solar-cycle variations of the quiet-Sun physical structure, such as the temperature gradient, might affect the irradiance. The…

Solar and Stellar Astrophysics · Physics 2018-09-05 M. Faurobert , M. Carbillet , L. Marquis , A. Chiavassa , G. Ricort

We compare the rms contrast in observed speckle reconstructed G-band images with synthetic filtergrams computed from two magneto-hydrodynamic simulation snapshots. The observations consist of 103 bursts of 80 frames each taken at the Dunn…

Astrophysics · Physics 2009-11-13 Han Uitenbroek , Alexandra Tritschler , Thomas Rimmele

The Helioseismic and Magnetic Imager (HMI) and the Atmospheric Imaging Assembly (AIA) instruments onboard the Solar Dynamics Observatory satellite produce Doppler velocity and continuum intensity at 6173 A as well as intensity maps at 1600…

Solar and Stellar Astrophysics · Physics 2015-06-17 Sebastien Couvidat

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

To study the structure of spatially unresolved features of the solar photosphere, we calculated the Stokes profiles of seven photospheric iron lines using two-dimensional nonstationary MHD models of solar granulation for various amounts of…

Solar and Stellar Astrophysics · Physics 2012-11-13 I. N. Atroshchenko , V. A. Sheminova

The aim of this work is to give new observational constraints on solar surface flows by determining the horizontal scale dependence of the velocity and intensity fields, as represented by their power spectra, and to offer some theoretical…

Solar and Stellar Astrophysics · Physics 2015-05-14 M. Rieutord , T. Roudier , F. Rincon , J. -M. Malherbe , N. Meunier , T. Berger , Z. Frank

We model the solar horizontal velocity power spectrum at scales larger than granulation using a two-component approximation to the mass continuity equation. The model takes four times the density scale height as the integral (driving) scale…

Solar and Stellar Astrophysics · Physics 2015-06-22 J. W. Lord , R. H. Cameron , M. P. Rast , M. Rempel , T. Roudier

The solar granulation is known for a long time to be a surface manifestation of convection. Thanks to the current space-borne missions CoRoT and Kepler, it is now possible to observe in disk-integrated intensity the signature of this…

Solar and Stellar Astrophysics · Physics 2015-06-17 R. Samadi , K. Belkacem , H. -G. Ludwig

Sunspots, faculae and the magnetic network contribute to solar irradiance variations. The contribution due to faculae and the network is of basic importance, but suffers from considerable uncertainty. We determine the contrasts of active…

Astrophysics · Physics 2009-11-07 A. Ortiz , S. K. Solanki , V. Domingo , M. Fligge , B. Sanahuja

Recent observations have shown that the photometric and dynamic properties of granulation and of small-scale magnetic features depend on the amount of magnetic flux of the region they are embedded in. We analyze results from numerical Hydro…

Solar and Stellar Astrophysics · Physics 2015-06-17 Serena Criscuoli

Context. Accurate photometry with ground based solar telescopes requires characterization of straylight. Scattering in Earth's atmosphere and in the telescope optics are potentially significant sources of straylight, for which the point…

Solar and Stellar Astrophysics · Physics 2016-01-13 Mats G. Löfdahl

Local-box hydrodynamical model atmospheres provide statistical information about a star's emergent radiation field which allows one to predict the level of its granulation-related micro-variability. Space-based photometry is now…

Solar and Stellar Astrophysics · Physics 2015-05-13 H. -G. Ludwig , R. Samadi , M. Steffen , T. Appourchaux , F. Baudin , K. Belkacem , P. Boumier , M. -J. Goupil , E. Michel