Beneath the fusion-encrusted surfaces of the most primitive stony meteorites lies not homogeneous rock, but a profusion of millimeter-sized igneous spheres. These chondrules, and their centimeter-sized counterparts, the calcium-aluminum-rich inclusions, comprise more than half of the volume fraction of chondritic meteorites. They are the oldest creations of the solar system. Their chemical comp...

Magnetic field modifies the properties of waves in a complex way. Significant advances has been made recently in our understanding of the physics of waves in solar active regions with the help of analytical theories, numerical simulations, as well as hi-resolution observations. In this contribution we review the current ideas in the field, with the emphasis on theoretical models of waves in sun...

We report results from self-consistent non-LTE radiation hydrodynamics simulations of the propagation of acoustic waves through the solar chromosphere. It is found that enhancedchromospheric emission, which correspondsto an outwardly increasing semi-empirical temperature structure, can be produced by wave motions without any increase in the mean gas temperature. Thus, despite long held beliefs,...

Context. Typical debris discs are composed of particles ranging from several micron sized dust grains to km sized asteroidal bodies, and their infrared emission peaks at wavelengths 60–100 μm. Recent Herschel DUNES observations have identified several debris discs around nearby Sun-like stars (F, G and K spectral type) with significant excess emission only at 160 μm. Aims. We observed HIP 92043...

Context. Typical debris discs are composed of particles ranging from several micron sized dust grains to km sized asteroidal bodies, and their infrared emission peaks at wavelengths 60–100 μm. Recent Herschel DUNES observations have identified several debris discs around nearby Sun-like stars (F, G and K spectral type) with significant excess emission only at 160 μm. Aims. We observed HIP 92043...

We analyze the evolution of shock waves in high-resolution 3D radiative MHD simulations quiet Sun and their synthetic emission characteristics. The model dynamics a 12.8x12.8x15.2 Mm quiet-Sun region (including 5.2 layer upper convection zone 10 atmosphere from photosphere to corona) with an initially uniform vertical magnetic field G, naturally driven by convective flows. synthesize Mg II C sp...

Abstract We present observations of NOAA AR 11159, obtained on 2011 February 14 in the 4.7 μ m band carbon monoxide (CO) and coordinated with spectroscopic imaging three atomic lines (Na i 5896 Å, Fe 7090 Ca ii 8542 Å) which sample heights from mid-photosphere to chromosphere. Phase-difference spectra between observed spectral instead indicate that CO form at z ≈ 530−650 km quiet Sun. During tw...

Context. The magnetic topology of the solar photosphere in its quietest regions is hidden by the difficulties to disentangle magnetic flux through the resolution element from the field strength of unresolved structures. The observation of spectral lines with strong coupling with hyperfine structure, like the observed Mn i line at 553.7 nm, allows such differentiation. Aims. To analyse the distr...

The precise nature of photospheric flows, and of the transport effects they give rise to, has been the subject of intense debate in the last decade. Here we attempt to give a brief review of the subject emphasizing interdisciplinary (solar physics—turbulence theory) aspects, key open questions, and recent developments.

Period-colour (PC) and amplitude-colour (AC) relations are studied for the Large Magellanic Cloud (LMC) Cepheids under the theoretical framework of the hydrogen ionization front (HIF) photosphere interaction. LMC models are constructed with pulsation codes that include turbulent convection, and the properties of these models are studied at maximum, mean and minimum light. As with Galactic model...