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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

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

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

We studied the radiative properties of small magnetic elements (active region faculae and the network) during the rising phase of solar cycle 23 from 1996 to 2001, determining their contrasts as a function of heliocentric angle, magnetogram…

Astrophysics · Physics 2009-11-11 Ada Ortiz , Vicente Domingo , Blai Sanahuja

Taken at a high spatial resolution of 0.1 arcsec, Bright Points (BPs) are found to coexist with faculae in images and the latter are often resolved as adjacent striations. Understanding the properties of these different features is…

Solar and Stellar Astrophysics · Physics 2014-10-21 P. Kobel , J. Hirzberger , S. K. Solanki

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 flux concentrations contribute significantly to the brightness variations of the Sun, yet observing them - particularly their magnetic field - near the solar limb remains challenging. Solar Orbiter offers an…

Solar and Stellar Astrophysics · Physics 2026-02-11 K. Albert , J. Hirzberger , N. A. Krivova , X. Li , D. Calchetti , G. Valori , J. Sinjan , S. K. Solanki , A. Gandorfer , J. Woch , D. Orozco Suárez , S. Parenti

While photospheric magnetic elements appear mainly as Bright Points (BPs) at the disk center and as faculae near the limb, high-resolution images reveal the coexistence of BPs and faculae over a range of heliocentric angles. This is not…

Solar and Stellar Astrophysics · Physics 2010-01-29 P. Kobel , J. Hirzberger , S. K. Solanki , A. Gandorfer , V. Zakharov

Previous studies have shown that the variation over the solar magnetic activity cycle of the area of facular/network features identified on broad band and narrow band imagery is positively correlated with the sunspot area and number, the…

Solar and Stellar Astrophysics · Physics 2016-07-20 Serena Criscuoli

Magnetic features on the surface of stars, such as spots and faculae, cause stellar spectral variability on time-scales of days and longer. For stars other than the Sun, the spectral signatures of faculae are poorly understood, limiting our…

The contrasts of features in the quiet Sun are studied using filtergrams recorded by the Broad-band Filter Imager on the Hinode/Solar Optical Telescope. In a first step, the scattered light originating in the instrument is modeled using…

Solar and Stellar Astrophysics · Physics 2015-05-13 S. K. Mathew , V. Zakharov , S. K. Solanki

Surfaces of the Sun and other cool stars are filled with magnetic fields, which are either seen as dark compact spots or more diffuse bright structures like faculae. Both hamper detection and characterisation of exoplanets, affecting…

Solar and Stellar Astrophysics · Physics 2022-08-03 N. -E. Nèmec , A. I. Shapiro , E. Işık , K. Sowmya , S. K. Solanki , N. A. Krivova , R. H. Cameron , L. Gizon

Variability observed in photometric lightcurves of late-type stars (on timescales longer than a day) is a dominant noise source in exoplanet surveys and results predominantly from surface manifestations of stellar magnetic activity, namely…

Polar faculae (PFe) are the footpoints of magnetic field lines near the Sun's poles that are seen as bright regions along the edges of granules. The time variation in the number of PFe has been shown to correlate with the strength of the…

Solar and Stellar Astrophysics · Physics 2022-04-26 Beryl Hovis-Afflerbach , W. Dean Pesnell

Solar irradiance variations over solar rotational time-scales are largely determined by the passage of magnetic structures across the visible solar disk. Variations on solar cycle time scales are thought to be similarly due to changes in…

Solar and Stellar Astrophysics · Physics 2015-08-19 Courtney Peck , Mark Rast

This paper studies the dependence of the CaIIH line core brightness on the strength and inclination of photospheric magnetic field, and on the parameters of convective and wave motions in a facular region at the solar disc center. We use…

Solar and Stellar Astrophysics · Physics 2016-04-06 R. Kostik , E. Khomenko

We present a PSF for SDO/HMI and discuss the effects of its removal on the apparent properties of solar surface phenomena in HMI data. The PSF was retrieved from observations of Venus in transit by matching it to the convolution of a model…

Solar and Stellar Astrophysics · Physics 2014-09-23 K. L. Yeo , A. Feller , S. K. Solanki , S. Couvidat , S. Danilovic , N. A. Krivova

We report a point spread function (PSF) and deconvolution procedure to remove stray light from the Helioseismic and Magnetic Imager (HMI) data. Pre-launch calibration observations, post-launch Venus transit and lunar transit data were used…

Solar and Stellar Astrophysics · Physics 2025-11-18 A. A. Norton , T. L. Duvall, , J. Schou , R. S. Bogart , J. Zhao , C. Rabello-Soares , P. J. Levens , J. T. Hoeksema , C. S. Baldner

When light is scattered or reflected accidentally in the lens, flare artifacts may appear in the captured photos, affecting the photos' visual quality. The main challenge in flare removal is to eliminate various flare artifacts while…

Computer Vision and Pattern Recognition · Computer Science 2024-06-27 Yiguo Jiang , Xuhang Chen , Chi-Man Pun , Shuqiang Wang , Wei Feng
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