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We present the first results of the application of supervised classification methods to the Kepler Q1 long-cadence light curves of a subsample of 2288 stars measured in the asteroseismology program of the mission. The methods, originally…

The K2 mission of the Kepler Space Telescope allowed the observations of light curves of small solar system bodies throughout the whole Solar system. In this paper we present the results of a collection of K2 transneptunian object…

This study applied machine learning models to estimate stellar rotation periods from corrected light curve data obtained by the NASA Kepler mission. Traditional methods often struggle to estimate rotation periods accurately due to noise and…

Solar and Stellar Astrophysics · Physics 2024-09-10 Fatemeh Fazel Hesar , Bernard Foing , Ana M. Heras , Mojtaba Raouf , Victoria Foing , Shima Javanmardi , Fons J. Verbeek

We present a test for spin-orbit alignment for the host stars of 25 candidate planetary systems detected by the {\it Kepler} spacecraft. The inclination angle of each star's rotation axis was estimated from its rotation period, rotational…

Earth and Planetary Astrophysics · Physics 2015-06-18 Teruyuki Hirano , Roberto Sanchis-Ojeda , Yoichi Takeda , Joshua N. Winn , Norio Narita , Yasuhiro H. Takahashi

Quasi-periodic pulsations (QPPs) appear to be a common feature observed in the light curves of both solar and stellar flares. However, their quasi-periodic nature, along with the fact that they can be small in amplitude and short-lived,…

Context. Studying the spots of late-type stars is crucial for distinguishing between the various proposed dynamo mechanisms believed to be the main cause of starspot activity. For this research it is important to collect observation time…

Solar and Stellar Astrophysics · Physics 2019-06-10 Thomas Hackman , Iya Ilyin , Jyri J. Lehtinen , Oleg Kochukhov , Maarit J. Käpylä , Nikolai Piskunov , Teemu Willamo

While the Kepler Mission was designed to look at tens of thousands of faint stars (V > 12), brighter stars that saturated the detector are important because they can be and have been observed very accurately by other instruments. By…

This work brings a wavelet analysis for 14 Kepler white dwarf stars, in order to confirm their photometric variability behavior and to search for periodicities in these targets. From the observed Kepler light curves we obtained the wavelet…

Solar and Stellar Astrophysics · Physics 2019-01-17 S. R. de Lira , J. P. Bravo , I. C. Leao , A. D. da Costa , B. L. Canto Martins , D. B. de Freitas , J. R. De Medeiros

Tens of thousands of rotation periods have been measured in the Kepler fields, including a substantial fraction of rapid rotators. We use Gaia parallaxes to distinguish photometric binaries (PBs) from single stars on the unevolved lower…

Solar and Stellar Astrophysics · Physics 2019-02-07 Gregory V. A. Simonian , Marc H. Pinsonneault , Donald M. Terndrup

We measure the binarity of detached M-dwarfs in the Kepler field with orbital periods in the range of 1-90 days. Kepler's photometric precision and nearly continuous monitoring of stellar targets over time baselines ranging from 3 months to…

Solar and Stellar Astrophysics · Physics 2015-11-04 Yutong Shan , John A. Johnson , Timothy D. Morton

The detection of small mass planets with the radial-velocity technique is now confronted with the interference of stellar noise. HARPS can now reach a precision below the meter-per-second, which corresponds to the amplitudes of different…

Earth and Planetary Astrophysics · Physics 2015-05-20 X. Dumusque , N. C. Santos , S. Udry , C. Lovis , X. Bonfils

Deep learning techniques are required for the analysis of synoptic (multi-band and multi-epoch) light curves in massive data of quasars, as expected from the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). In this…

A multifractal formalism is employed to analyse high-precision time-series data of \textit{Kepler} stars with surface differential rotation traces. The multifractal detrended moving average analysis (MFDMA) algorithm has been explored to…

Solar and Stellar Astrophysics · Physics 2019-08-07 D. B. de Freitas , M. M. F. Nepomuceno , J. G. Cordeiro , M. L. Das Chagas , J. R. De Medeiros

This work aims to develop a computationally inexpensive approach, based on machine learning techniques, to accurately predict thousands of stellar rotation periods. The innovation in our approach is the use of the XGBoost algorithm to…

Solar and Stellar Astrophysics · Physics 2024-10-02 Nuno R. C. Gomes , Fabio Del Sordo , Luís Torgo

Context. The Sun and solar-like stars undergo activity cycles for which the underlying mechanisms are not well understood. The oscillations of the Sun are known to vary with its activity cycle and these changes provide diagnostics on the…

Solar and Stellar Astrophysics · Physics 2017-02-08 René Kiefer , Ariane Schad , Guy Davies , Markus Roth

We have monitored 20 Sun-like stars in the Kepler field-of-view for excess flux with the FIES spectrograph on the Nordic Optical Telescope since the launch of Kepler spacecraft in 2009. These 20 stars were selected based on their…

HD 208472 is among the most active RS~CVn binaries with cool starspots. Decade-long photometry has shown that the spots seem to change their longitudinal appearance with a period of about six years, coherent with brightness variations. Our…

Solar and Stellar Astrophysics · Physics 2016-10-05 O. Özdarcan , T. A. Carroll , A. Künstler , K. G. Strassmeier , S. Evren , M. Weber , T. Granzer

We systematically searched for gravity- and Rossby-mode period spacing patterns in Kepler eclipsing binaries with $\gamma$ Doradus pulsators. These stars provide an excellent opportunity to test the theory of tidal synchronisation and…

Solar and Stellar Astrophysics · Physics 2020-08-12 Gang Li , Zhao Guo , Jim Fuller , Timothy R. Bedding , Simon J. Murphy , Isabel L. Colman , Daniel R. Hey

We carried out light curve solutions of ten detached eclipsing eccentric binaries observed by Kepler. The formal errors of the derived parameters from the light curve solutions are below 1%. Our results give indications that the components…

Solar and Stellar Astrophysics · Physics 2016-05-25 D. Kjurkchieva , D. Vasileva

We present an analytic model of the lightcurve variation for stars with non-evolving starspots on a differentially rotating surface. The Fourier coefficients of the harmonics of the rotation period are expressed in terms of the latitude of…

Solar and Stellar Astrophysics · Physics 2022-08-17 Yasushi Suto , Shin Sasaki , Yuta Nakagawa , Othman Benomar