Publications (17)
Helium Emissions Observed in Ground-Based Spectra of Solar Prominences
Renzo Ramelli, Goetz Stellmacher, Eberhard Wiehr +1
The only prominent line of singly ionized helium in the visible spectral range, helium-II 4686 A, is observed together with the helium-I 5015 A singlet and the helium-I 4471 A trip…
Star-planet interactions: I. Stellar rotation and planetary orbits
Giovanni Privitera, Georges Meynet, Patrick Eggenberger +3
Context. As a star evolves, the planet orbits change with time due to tidal interactions, stellar mass losses, friction and gravitational drag forces, mass accretion and evaporatio…
Comparison of theoretical and observed Ca~{\sc ii}~8542 Stokes profiles in quiet regions at the centre of the solar disc
Jan Jurcak, Jiri Stepan, Javier Trujillo Bueno +1
Interpreting the Stokes profiles observed in quiet regions of the solar chromosphere is a challenging task. The Stokes Q and U profiles are dominated by the scattering polarisation…
High surface magnetic field in red giants as a new signature of planet engulfment?
Giovanni Privitera, Georges Meynet, Patrick Eggenberger +6
Context. Red-giant stars may engulf planets. This may increase the rotation rate of their convective envelope, which could lead to strong dynamo-triggered magnetic fields. Aims. We…
Measurement of the evolution of the magnetic field of the quiet photosphere during a solar cycle
Renzo Ramelli, Michele Bianda, Svetlana Berdyugina +2
The solar photosphere is filled by a magnetic field which is tangled on scales much smaller than the resolution capability of solar telescopes. This hidden magnetic field can be in…
The power spectrum of the seeing during solar observations
Costantino Sigismondi, Andrea Raponi, Xiaofan Wang +3
Measurements of the power spectrum of the atmospheric seeing in the line of sight of the Sun, in the range 0.001-1 Hz, have been performed in Santa Maria degli Angeli Lucernaria Do…
Star-planet interactions: II. Is planet engulfment the origin of fast rotating red giants?
Giovanni Privitera, Georges Meynet, Patrick Eggenberger +3
Context. Fast rotating red giants in the upper part of the red giant branch have surface velocities that cannot be explained by single star evolution. Aims. We check whether tides…
Hanle rotation signatures in Sr I 4607 Ã
Franziska Zeuner, Luca Belluzzi, Nuno Guerreiro +2
Observations of scattering polarization and the Hanle effect in various spectral lines are increasingly used to complement traditional solar magnetic field determination techniques…
Observations on spatial variations of the Sr~{\sc i} 4607~Ã ~scattering polarization signals at different limb distances with ZIMPOL
Sajal Kumar Dhara, Emilia Capozzi, Daniel Gisler +5
The Sr~{\sc i} 4607~Ã spectral line shows one of the strongest scattering polarization signals in the visible solar spectrum. The amplitude of this polarization signal is expected…
Evidence for the two fluid scenario in solar prominences
Eberhard Wiehr, Götz Stellmacher, Michele Bianda
This paper presents observational evidence of the different dynamical behavior of neutral and ionized species in solar prominences. The analysis of a time-series of Sr II 4078 A an…
Sunspot data collection of Specola Solare Ticinese in Locarno
Renzo Ramelli, Marco Cagnotti, Sergio Cortesi +2
Sunspot observations and counting are carried out at the Specola Solare Ticinese in Locarno since 1957 when it was built as an external observing station of the Zurich observatory.…
Sunspot Observations and Counting at Specola Solare Ticinese in Locarno since 1957
Sergio Cortesi, Marco Cagnotti, Michele Bianda +2
Specola Solare Ticinese is an observatory dedicated to Sunspot Number counting, which was constructed in 1957 in Locarno, Southern Switzerland, as an external observing station of…
Atmospheric fluctuations below 0.1 Hz during drift-scan solar diameter measurements
Costantino Sigismondi, Andrea Raponi, Giulia De Rosi +6
Measurements of the power spectrum of the seeing in the range 0.001-1 Hz have been performed in order to understand the criticity of the transits' method for solar diameter monitor…
Spatial variations of the SrI 4607Ã scattering polarization signals at subgranular scale observed with ZIMPOL at GREGOR telescope
Sajal Kumar Dhara, Emilia Capozzi, Daniel Gisler +5
Sr I 4607Ã spectral line shows one of the strongest scattering polarization signals in the visible solar spectrum. The amplitudes of these signals are expected to vary at granular…
He-D3 Polarization observed in Prominences
Renzo Ramelli, Michele Bianda
Spectro-polarimetric measurements of the D3-HeI 5876 A line profile in 35 prominences have been performed in 2003 with the Gregory-Coudé Telescope in Locarno. Two different experi…
Scattering polarization and the Hanle effect in H-alpha as a probe of chromospheric magnetism: Modeling vs. Observations
Jiri Stepan, Javier Trujillo Bueno, Renzo Ramelli +1
The Hanle effect in strong spectral lines is the physical mechanism that should be increasingly exploited for quantitative explorations of the magnetism of the quiet solar chromosp…
Velocity difference of ions and neutrals in solar prominences
Eberhard Wiehr, Goetz Stellmacher, Horst Balthasar +1
Marked velocity excesses of ions relative to neutrals are obtained from two time series of the neighboring emission lines He I 5015 and Fe II 5018 in a quiescent prominence. Their…