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Differences in the ingress and egress shapes of transit light curves can indicate morning-evening temperature contrasts on transiting planets. Here, we pinpoint an alternative mechanism that can introduce asymmetries in transit light…

Solar and Stellar Astrophysics · Physics 2025-07-23 N. Kostogryz , A. I. Shapiro , L. Carone , L. Gizon , Ch. Helling , S. Kiefer , S. Mercier , S. Seager , S. K. Solanki , Y. Unruh , J. de Wit , V. Witzke

Using Greenwich sunspot data for 120 years it was recently observed that activity regions on the Sun's surface tend to lie along smoothly changing longitude strips 180 degrees apart from each other. However, numerical experiments with…

Astrophysics · Physics 2009-11-10 J. Pelt , I. Tuominen , J. Brooke

We compute f-mode travel-time sensitivity kernels for flows. Using a two-dimensional model, we show that it is important to account for several systematic effects, such as the foreshortening and the projection of the velocity vector onto…

Astrophysics · Physics 2007-05-23 J. Jackiewicz , L. Gizon , A. Birch

The solar modulation effect of Galactic cosmic rays is a time-dependent phenomenon that is caused by the transport of these particles through the magnetized plasma of the heliosphere. Using a data-driven model of cosmic-ray transport in the…

High Energy Astrophysical Phenomena · Physics 2019-05-22 Miguel Orcinha , Nicola Tomassetti , Fernando Barão , Bruna Bertucci

We investigate the structure of the solar chromosphere and transition region using full Sun images obtained with the Extreme Ultraviolet Imaging Telescope (EIT) aboard the Solar and Heliospheric Observatory (SOHO) spacecraft. The limb seen…

Astrophysics · Physics 2009-10-30 J. Zhang , S. M. White , M. R. Kundu

We present the estimation of the solar observation with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). For both the quite Sun and the Sun with radio bursts, when pointing directly to the Sun, the total power received by…

Instrumentation and Methods for Astrophysics · Physics 2023-01-04 Lei Qian , Zhichen Pan , Hongfei Liu , Hengqian Gan , Jinglong Yu , Lei Zhao , Jiguang Lu , Cun Sun , Jingye Yan , Peng Jiang

Integration of intermittent renewable energy sources into electric grids in large proportions is challenging. A well-established approach aimed at addressing this difficulty involves the anticipation of the upcoming energy supply…

Computer Vision and Pattern Recognition · Computer Science 2022-06-08 Quentin Paletta , Guillaume Arbod , Joan Lasenby

The Carte Synoptique catalogue of solar filaments from March 1919 to December 1989, corresponding to complete cycles 16 to 21 is utilized to show latitudinal migration of filaments at low latitudes (less than 50 deg), and the latitudinal…

Solar and Stellar Astrophysics · Physics 2015-05-18 K. J. Li

Some active stars show a so-called flip-flop phenomenon in which the main spot activity periodically switches between two active longitudes that are 180 degrees apart. In this paper we study the flip-flop phenomenon by converting results…

Astrophysics · Physics 2009-11-11 H. Korhonen , D. Elstner

It is customary to employ a semi-spherical scale model to describe the apparent path of the Sun across the sky, whether it be its diurnal motion or its variation throughout the year. A flat surface and three bent semi-rigid wires…

Popular Physics · Physics 2018-09-25 Alejandro Gangui , Roberto Casazza , Carlos Paez

We use the magnetic butterfly diagram to determine the speed of the magnetic flux transport on the solar surface towards the poles. The manifestation of the flux transport is clearly visible as elongated structures extended from the sunspot…

Astrophysics · Physics 2009-11-13 M. Svanda , A. G. Kosovichev , J. Zhao

Point lens microlensing events with impact parameter close to the source stellar radius allow the observer to study the surface brightness profile of the lensed source. We have examined the effect of photospheric star spots on multicolour…

Astrophysics · Physics 2009-11-07 M. A. Hendry , H. M. Bryce , D. Valls-Gabaud

Aims: Our goal is to develop methodologies to seamlessly track transient solar wind flows viewed by coronagraphs or heliospheric imagers from rapidly varying viewpoints. Methods: We constructed maps of intensity versus time and elongation…

Solar and Stellar Astrophysics · Physics 2021-06-02 A. Nindos , S. Patsourakos , A. Vourlidas , P. C. Liewer , P. Penteado , J. R. Hall

Measurements from the Solar Irradiance Monitor (SIM) onboard the SORCE mission indicate that solar spectral irradiance at Visible and IR wavelengths varies in counter phase with the solar activity cycle. The sign of these variations is not…

Solar and Stellar Astrophysics · Physics 2015-06-19 Serena Criscuoli , Han Uitenbroek

The transit method, employed by MOST, \emph{Kepler}, and various ground-based surveys has enabled the characterization of extrasolar planets to unprecedented precision. These results are precise enough to begin to measure planet atmosphere…

Earth and Planetary Astrophysics · Physics 2017-08-23 Hilding R. Neilson , Joseph T. McNeil , Richard Ignace , John B. Lester

Both GONG and MDI projects have measured {\it p}-mode frequencies of the Sun for more than 7 years. Here we review what we have learnt from the temporal variation of the oscillation frequencies and splitting coefficients.

Astrophysics · Physics 2007-05-23 S. C. Tripathy

Context. Monitoring of the photometric and chromospheric HK emission data series of stars similar to the Sun in age and average activity level showed that there is an empirical correlation between the average stellar chromospheric activity…

Solar and Stellar Astrophysics · Physics 2015-06-15 A. I. Shapiro , W. Schmutz , G. Cessateur , E. Rozanov

Observations of magnetic helicity transportation through the solar photosphere reflect the interaction of turbulent plasma movements and magnetic fields in the solar dynamo process. In this chapter, we have reviewed the research process of…

Solar and Stellar Astrophysics · Physics 2023-11-14 Hongqi Zhang , Shangbin Yang , Haiqing Xu , Xiao Yang , Jie Chen , Jihong Liu

We present independent observations of the solar-cycle variation of flows near the solar surface and at a depth of about 60 Mm, in the latitude range $\pm45^\circ$. We show that the time-varying components of the meridional flow at these…

Astrophysics · Physics 2009-11-13 L. Gizon , M. Rempel

We show how magnetic observations of the Sun can be used in conjunction with an axisymmetric flux-transport solar dynamo model in order to estimate the large-scale meridional circulation throughout the convection zone. Our innovative…

Solar and Stellar Astrophysics · Physics 2017-10-06 Ching Pui Hung , Laurène Jouve , Allan Sacha Brun , Alexandre Fournier , Olivier Talagrand