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Related papers: Building a Large Solar Analog Sample Using K2

200 papers

Measurements of the ionized Ca II K line are one of the major resources for long-term studies of solar and stellar activity. They also play a critical role in many studies related to solar irradiance variability, particularly as a…

Solar and Stellar Astrophysics · Physics 2015-05-28 Luca Bertello , Alexei A. Pevtsov , Jack W. Harvey , Roberta M. Toussaint

Recent studies of solar-type superflare stars have suggested that even old slowly rotating stars similar to the Sun can have large starspots and superflares. We conducted high dispersion spectroscopy of 49 nearby solar-analog stars (G-type…

Solar and Stellar Astrophysics · Physics 2017-01-26 Yuta Notsu , Satoshi Honda , Hiroyuki Maehara , Shota Notsu , Kosuke Namekata , Daisaku Nogami , Kazunari Shibata

An orbiting `photon clock' is proposed to test directly the relativity of simultaneity effect of special relativity. This is done by exchanging microwave signals between two satellites in low Earth orbit carrying clocks that have previously…

General Physics · Physics 2011-06-06 J. H. Field

We study the relationship between full-disk solar radiative flux at different wavelengths and average solar photospheric magnetic-flux density, using daily measurements from the Kitt Peak magnetograph and other instruments extending over…

Solar and Stellar Astrophysics · Physics 2010-06-23 Dora Preminger , Dibyendu Nandy , Gary Chapman , Petrus C. H. Martens

In this paper, we demonstrate the importance of embedding temporal information for an accurate prediction of solar irradiance. We have used two sets of models for forecasting solar irradiance. The first one uses only time series data of…

Solar and Stellar Astrophysics · Physics 2021-10-20 T. A. Fathima , Vasudevan Nedumpozhimana , Yee Hui Lee , Soumyabrata Dev

This study attempts to establish a basis for understanding how methods used in research in solar physics have evolved since World War II (WWII). The goal is to begin to explore if and how the changing research environment affects the…

Instrumentation and Methods for Astrophysics · Physics 2025-05-26 Philip G. Judge

We present a method of chromospheric flux simulation for 13 late-type main-sequence stars. These Sun-like stars have well-determined cyclic flux variations similar to 11 yr solar activity cycle. Our flux prediction is based on chromospheric…

Solar and Stellar Astrophysics · Physics 2015-05-20 E. A. Bruevich

Adaptive Optics (AO) systems have become integral for ground-based astronomy. Based on the scientific case, there are various flavours of AO systems. Measuring the turbulence strength profile ($C_N^2(h)$) and other site characteristics is…

Instrumentation and Methods for Astrophysics · Physics 2023-10-19 Saraswathi Kalyani Subramanian , Sridharan Rengaswamy

To expand the range in the colour-magnitude diagram where asteroseismology can be applied, we organized a photometry campaign to find evidence for solar-like oscillations in giant stars in the globular cluster M4. The aim was to detect the…

Using wavelet analysis approach, the temporal variations of solar activity on time scales ranging from days to decades, are examined from the daily time series of sunspot numbers. A hierarchy of changing complex periods are careful detected…

Data Analysis, Statistics and Probability · Physics 2007-05-23 Stefano Sello

Previous measurements of stellar properties for K2 stars in the Ecliptic Plane Input Catalog (EPIC; Huber et al. 2016) largely relied on photometry and proper motion measurements, with some added information from available spectra and…

In this work we use solar observations with the ALMA radio telescope at the wavelength of 1.21 mm. The aim of the analysis is to improve understanding of the solar chromosphere, a dynamic layer in the solar atmosphere between the…

Solar and Stellar Astrophysics · Physics 2018-12-19 R. Brajša , D. Sudar , I. Skokic , A. O. Benz , M. Kuhar , A. Kobelski , S. Wedemeyer , S. M. White , H. -G. Ludwig , M. Temmer , S. H. Saar , C. L. Selhorst

Image alignment plays a crucial role in solar physics research, primarily involving translation, rotation, and scaling. \G{The different wavelength images of the chromosphere and transition region have structural complexity and differences…

Instrumentation and Methods for Astrophysics · Physics 2025-03-17 Yun Wang , KaiFan Ji , Zhenyu Jin , Hui Liu

In the "post-Moore era", the growing challenges in traditional computing have driven renewed interest in analog computing, leading to various proposals for the development of general-purpose analog computing (GPAC) systems. In this work, we…

Estimation of time delays from a noisy and gapped data is one of the simplest data analysis problems in astronomy by its formulation. But as history of real experiments show, the work with observed data sets can be quite complex and…

Instrumentation and Methods for Astrophysics · Physics 2011-05-31 A. Hirv , N. Olspert , J. Pelt

The Kepler space telescope yielded unprecedented data for the study of solar-like oscillations in other stars. The large samples of multi-year observations posed an enormous data analysis challenge that has only recently been surmounted.…

The study of the differential rotation in the chromosphere of the Sun is of significant importance as it provides valuable insights into the rotational behaviour of the solar atmosphere at higher altitudes and the coupling mechanism between…

Solar and Stellar Astrophysics · Physics 2024-12-25 Dibya Kirti Mishra , Srinjana Routh , Bibhuti Kumar Jha , Subhamoy Chatterjee , Dipankar Banerjee

We applied the method of continuous wavelet-transform to high-quality time-frequency analysis to the sets of observations of relative sunspot numbers. Wavelet analysis of these data reveals the following pattern: at the same time there are…

Solar and Stellar Astrophysics · Physics 2015-12-15 A. A. Borisov , E. A. Bruevich , V. V. Bruevich , I. K. Rozgacheva , E. V. Shimanovskaya

A next generation of space-based observatories aims to detect and characterize potentially Earth-like exoplanets around Sun-like stars using reflected light spectroscopy. However, it remains unclear how such direct imaging…

Earth and Planetary Astrophysics · Physics 2025-10-28 Arnaud Salvador , Tyler D. Robinson

We proposed an analytical model for the calculus of illumination time of the Earth for any time of year and any latitude, this model assumes the obliquity of the ecliptic as constant, the light beams as parallels, the Earth as spherical,…

Earth and Planetary Astrophysics · Physics 2012-10-15 Paco Talero , Fernanda Santana , César Mora