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Category/Subcategory: Natural Sciences/Astronomy


Author: Judith Palacios
In this work we follow a series of papers on high-resolution solar observations (Balmaceda et al. 2009, Balmaceda et al. 2010, Vargas Dominguez et al. 2011, Palacios et al. 2012, Vargas Domínguez et al 2015, Cabello et al., in pr ... more

Views: 455

Empirical Mode Decomposition studies of quasi-biennial variations in helioseismic frequencies

Author: Anne-Marie Broomhall
It is well-known that the Sun’s magnetic activity varies primarily on a time scale of 11yrs. It is also well known that the frequencies of the Sun’s natural acoustic oscillations vary in-phase with surface and atmospheric me ... more

Views: 481

16CygA&B and Kepler Legacy values : Differences between the values of frequencies by different fitters

Author: Ian Roxburgh
The differences between the oscillation frequencies and uncertainty estimates of a star derived by different fitters can be large, sufficiently large so that, were one to find a stellar model that fitted one frequency set ($\chi^ ... more

Views: 885

20 Years of GONG: p Mode Parameters and the Solar Cycle

Author: René Kiefer
The properties of solar acoustic oscillations are known to vary with the solar cycle. With 20 years of continuous observations by GONG, we are now in the position to carry out a comparison of the variation of the p mode parameters ... more

Views: 416

Photosphere and chromosphere telescope at Hvar Observatory

Author: Jaša Čalogović
The double solar telescope at the Hvar Observatory consists of two Carl Zeiss refractors, attached as one unit on a German parallax mounting. The photosphere telescope has an objective diameter of 217 mm and the chromosphere teles ... more

Views: 367

Preliminary Results from a Coronal Oscillations Instrument during the 2017 Total Eclipse

Author: Pawel Rudawy
An instrument using fast-frame cameras has been used during several recent total solar eclipses to search for oscillations in the green-line coronal emission. A much more sophisticated version of the instrument was prepared, teste ... more

Views: 21

Non-LTE inversion of spectropolarimetric and spectroscopic observations of a small active-region filament observed at the VTT

Author: Pavol Schwartz
An active-region filament in the active region NOAA 12159 (at solar disk coordinates [x,y] = [225,-440] arcsec) was observed with the Vacuum Tower Telescope at Tenerife on 11 September 2014. Full-Stokes spectropolarimetric observa ... more

Views: 606

Reconnection between emerging and pre-existing magnetic fields observed with IRIS: a case study for EST observations

Author: Salvo Guglielmino
We report multi-wavelength ultraviolet observations taken with the IRIS satellite, concerning the emergence phase in the upper chromosphere and transition region of an emerging flux region (EFR) embedded in the unipolar plage of a ... more

Views: 24

The K2 RR Lyrae survey

Author: Robert Szabo
We have initiated a large survey with K2, to observe thousands of RR Lyrae stars along the ecliptic. The high photometric precision and the 80-90-day continuous coverage will allow us to investigate the light variation of these ga ... more

Views: 396

Stellar Parameters in an Instant with Machine Learning

Author: Earl Bellinger
We use machine learning to build a constrained multiple regression model for rapidly estimating the fundamental stellar parameters of main-sequence solar-like stars (Bellinger & Angelou 2016). We train a random forest of decision ... more

Views: 491