English
Related papers

Related papers: Low frequency seeing and solar diameter measuremen…

200 papers

Within the quiet Sun corona imaged at 1 MK, much of the field of view consists of diffuse emission that appears to lack the spatial structuring that is so evident in coronal loops or bright points. We seek to determine if these diffuse…

The solar surface and atmosphere are highly dynamic plasma environments, which evolve over a wide range of temporal and spatial scales. Large-scale eruptions, such as coronal mass ejections, can be accelerated to millions of kilometres per…

The total amount of solar irradiance falling on the earth's surface is an important area of study amongst the photo-voltaic (PV) engineers and remote sensing analysts. The received solar irradiance impacts the total amount of generated…

Instrumentation and Methods for Astrophysics · Physics 2018-04-23 Shilpa Manandhar , Soumyabrata Dev , Yee Hui Lee , Yu Song Meng

A method to measure the seeing from video made during drift-scan solar transits is proposed. The limb of the Sun is projected over a regular grid evenly spaced. The temporal dispersion of the time intervals among the contacts between solar…

Instrumentation and Methods for Astrophysics · Physics 2011-06-14 Costantino Sigismondi

The net effect of the small scale magnetic field on the Sun's (bolometric) brightness is studied with realistic 3D MHD simulations. The direct effect of brightening within the magnetic field itself is consistent with measurements in…

Solar and Stellar Astrophysics · Physics 2020-02-12 I. Thaler , H. C. Spruit

Adiabatic oscillation frequencies of stellar models, computed with the standard mixing-length formulation for convection, increasingly deviate with radial order from observations in solar-like stars. Standard solar models overestimate…

Solar and Stellar Astrophysics · Physics 2016-11-15 G. Houdek , R. Trampedach , M. J. Aarslev , J. Christensen-Dalsgaard

A measurement by microlensing of the planetary mass function of planets with masses ranging from 5M_E to 10M_J and orbital radii from 0.5 to 10 AU was reported recently. A strategy for extending the mass range down to (1-3)M_E is proposed…

We describe systematic changes in the centroid frequencies and the splitting coefficients as found using data from MDI on board SOHO, covering cycle 23. The data allow us to construct a seismic map of the evolving solar activity -- covering…

Astrophysics · Physics 2007-05-23 W. A. Dziembowski , Philip R. Goode

The measurement of the Sun's diameter has been first tackled by the Greek astronomers from a geometric point of view. Their estimation of ~1800", although incorrect, was not truly called into question for several centuries. The first…

Solar and Stellar Astrophysics · Physics 2018-04-20 J. P. Rozelot , A. G. Kosovichev , A. Kilcik

High-frequency wave phenomena present a great deal of interest as one of the possible candidates to contribute to the energy input required to heat the corona as a part of the AC heating theory. However, the resolution of imaging…

Solar and Stellar Astrophysics · Physics 2023-04-05 Elena Petrova , Norbert Magyar , Tom Van Doorsselaere , David Berghmans

The Sun shrinks during solar maximum and regrows during solar minimum by a few kilometers. Here, we observe, for the first time, that the solar radius variation shows planetary relationship. This suggests that some remote planetary links…

General Physics · Physics 2022-02-10 Konstantin Zioutas , Marios Maroudas , Alexander Kosovichev

Recently, the availability of new high-spatial and -temporal resolution observations of the solar photosphere has allowed the study of the oscillations in small magnetic elements. Small magnetic elements have been found to host a rich…

Solar and Stellar Astrophysics · Physics 2015-06-17 M. Stangalini , F. Berrilli , G. Consolini

Modern radio telescopes are extremely sensitive to plasma on the line of sight from a radio source to the antenna. Plasmas in the corona and solar wind produce measurable changes in the radio wave amplitude and phase, and the phase…

Astrophysics · Physics 2009-11-13 Steven R. Spangler , Catherine A. Whiting

Minor bodies of the solar system can be used to measure the spectrum of the Sun as a star by observing sunlight reflected by their surfaces. To perform an accurate measurement of the radial velocity of the Sun as a star by this method, it…

Solar and Stellar Astrophysics · Physics 2015-05-06 A. F. Lanza , P. Molaro

We find evidence for the first observation of the parametric decay instability (PDI) in the lower solar atmosphere. Specifically, we find that the power spectrum of density fluctuations near the solar transition region resembles the power…

Solar and Stellar Astrophysics · Physics 2022-07-20 Michael Hahn , Xiangrong Fu , Daniel Wolf Savin

We show in this paper that the changes of the solar diameter in response to variations of large scale magnetic fields and turbulence are not homologous. For the best current model, the variation at the photospheric level is over 1000 times…

Astrophysics · Physics 2016-08-16 Sabatino Sofia , Sarbani Basu , Pierre Demarque , Linghuai Li , Gerard Thuillier

The quiet solar corona emits meter-wave thermal bremsstrahlung. Coronal radio emission can only propagate above that radius, $R_\omega$, where the local plasma frequency eqals the observing frequency. The radio interferometer LOw Frequency…

Solar and Stellar Astrophysics · Physics 2018-06-13 C. Vocks , G. Mann , F. Breitling , M. M. Bisi , B. Dabrowski , R. Fallows , P. T. Gallagher , A. Krankowski , J. Magdalenic , C. Marque , D. Morosan , H. Rucker

Frequency and rotational splittings of the solar f-modes are estimated from the GONG data. Contrary to earlier observations the frequencies of f-modes are found to be close to the theoretically computed values for a standard solar model.…

Astrophysics · Physics 2008-11-26 H. M. Antia

Frequency splitting coefficients from Global Oscillation Network Group (GONG) and Michelson Doppler Imager (MDI) observations covering the period 1995--2001 are used to study temporal variations in the solar rotation rate at high latitudes.…

Astrophysics · Physics 2009-11-07 H. M. Antia , Sarbani Basu

Clouds cast shadows on the surface and locally enhance solar irradiance by absorbing and scattering sunlight, resulting in fast and large solar irradiance fluctuations on the surface. Typical spatiotemporal scales and driving mechanisms of…

Atmospheric and Oceanic Physics · Physics 2023-03-09 Wouter Mol , Bart van Stratum , Wouter Knap , Chiel van Heerwaarden