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Related papers: Connecting measurements of solar and stellar brigh…

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Magnetic features on the surfaces of cool stars cause variations of their brightness. Such variations have been extensively studied for the Sun. Recent planet-hunting space telescopes allowed measuring brightness variations in hundred…

Solar and Stellar Astrophysics · Physics 2020-04-15 N. -E. Nèmec , A. I. Shapiro , N. A. Krivova , S. K. Solanki , R. V. Tagirov , R. H. Cameron , S. Dreizler

Regular spaceborne measurements have revealed that solar brightness varies on multiple timescales, variations on timescales greater than a day being attributed to surface magnetic field. Independently, ground-based and spaceborne…

Solar and Stellar Astrophysics · Physics 2016-04-27 A. I. Shapiro , S. K. Solanki , N. A. Krivova , K. L. Yeo , W. K. Schmutz

Aims: We investigate how well modeled solar irradiances agree with measurements from the SORCE satellite, both for total solar irradiance and broken down into spectral regions on timescales of several years. Methods: We use the SATIRE model…

Solar and Stellar Astrophysics · Physics 2015-05-27 Will T. Ball , Yvonne C. Unruh , Natalie A. Krivova , Sami Solanki , Jerald W. Harder

The unprecedented precision of broadband stellar photometry achieved with the planet-hunting missions CoRoT and \textit{Kepler} initiated a new era in examining the magnetically-driven brightness variations of hundreds of thousands of…

Solar and Stellar Astrophysics · Physics 2021-06-25 Nina-Elisabet Nèmec

Aims: We test the reliability of the observed and calculated spectral irradiance variations between 200 and 1600 nm over a time span of three solar rotations in 2004. Methods: We compare our model calculations to spectral irradiance…

Astrophysics · Physics 2009-11-13 Yvonne C. Unruh , Natalie A. Krivova , Sami K. Solanki , Jerald W. Harder , Greg Kopp

Young and active stars generally have regular, almost sinusoidal, patterns of variability attributed to their rotation, while the majority of older and less active stars, including the Sun, have more complex and non-regular light-curves…

Solar and Stellar Astrophysics · Physics 2020-04-22 E. M. Amazo-Gómez , A. I. Shapiro , S. K. Solanki , N. A. Krivova , G. Kopp , T. Reinhold , M. Oshagh , A. Reiners

The Sun's net radiative output varies on timescales of minutes to gigayears. Direct measurements of the total solar irradiance (TSI) show changes in the spatially- and spectrally-integrated radiant energy on timescales as short as minutes…

Solar and Stellar Astrophysics · Physics 2016-07-04 Greg Kopp

Due to non-homogeneous mass distribution and non-uniform velocity rate inside the Sun, the solar outer shape is distorted in latitude. In this paper, we analyze the consequences of a temporal change in this figure on the luminosity. To do…

Solar and Stellar Astrophysics · Physics 2011-08-31 Z. Fazel , J. P. Rozelot , S. Lefebvre , A. Ajabshirizadeh , S. Pireaux

The amplitude and morphology of light curves of solar-like stars change substantially with increasing rotation rate: brightness variations get amplified and become more regular, which has so far not been explained. We develop a modelling…

Solar and Stellar Astrophysics · Physics 2023-04-19 N. -E. Nèmec , A. I. Shapiro , E. Işik , S. K. Solanki , T. Reinhold

We analyze the effect of solar features on the variability of the solar irradiance in three different spectral ranges. Our study is based on two solar-cycles' worth of full-disk photometric images from the San Fernando Observatory, obtained…

Solar and Stellar Astrophysics · Physics 2015-05-28 Dora Preminger , Gary Chapman , Angela Cookson

The Sun and stars with low magnetic activity levels, become photometrically brighter when their activity increases. Magnetically more active stars display the opposite behaviour and get fainter when their activity increases. We reproduce…

Solar and Stellar Astrophysics · Physics 2015-06-19 A. I. Shapiro , S. K. Solanki , N. A. Krivova , W. K. Schmutz , W. T. Ball , R. Knaack , E. V. Rozanov , Y. C. Unruh

The variation in the radiative output of the Sun, described in terms of solar irradiance, is important to climatology. A common assumption is that solar irradiance variability is driven by its surface magnetism. Verifying this assumption…

Solar and Stellar Astrophysics · Physics 2017-09-05 K. L. Yeo , S. K. Solanki , C. M. Norris , B. Beeck , Y. C. Unruh , N. A. Krivova

Context. Solar spectral irradiance (SSI) variability is one of the key inputs to models of the Earth's climate. Understanding solar irradiance fluctuations also helps to place the Sun among other stars in terms of their brightness…

Solar and Stellar Astrophysics · Physics 2019-11-20 R. V. Tagirov , A. I. Shapiro , N. A. Krivova , Y. C. Unruh , K. L. Yeo , S. K. Solanki

The Sun has long been considered a constant star, to the extent that its total irradiance was termed the solar constant. It required radiometers in space to detect the small variations in solar irradiance on timescales of the solar rotation…

Solar and Stellar Astrophysics · Physics 2015-06-11 Sami K. Solanki , Yvonne C. Unruh

Context. Comparison studies of Sun-like stars with the Sun suggest an anomalously low photometric variability of the Sun compared to Sun-like stars with similar magnetic activity. Comprehensive understanding of stellar variability is…

Solar and Stellar Astrophysics · Physics 2018-11-21 V. Witzke , A. I. Shapiro , S. K. Solanki , N. A. Krivova , W. Schmutz

Total and spectral solar irradiance are key parameters in the assessment of solar influence on changes in the Earth's climate. We present a reconstruction of daily solar irradiance obtained using the SATIRE-S model spanning 1974 to 2013…

Solar and Stellar Astrophysics · Physics 2015-07-07 K. L. Yeo , N. A. Krivova , S. K. Solanki , K. H. Glassmeier

Rotational variables are stars that vary in brightness due to star spots modulated by rotation. They are probes of stellar magnetism, binarity, and evolution. Phillips et al. (2023) explored distinct populations of ~50,000 high-amplitude…

Solar and Stellar Astrophysics · Physics 2025-06-18 Jack Stethem , Christopher S. Kochanek , Anya Phillips , Lyra Cao , Marc Pinsonneault

Total solar irradiance and UV spectral solar irradiance have been monitored since 1978 through a succession of space missions. This is accompanied by the development of models aimed at replicating solar irradiance by relating the…

Solar and Stellar Astrophysics · Physics 2015-07-07 K. L. Yeo , W. T. Ball , N. A. Krivova , S. K. Solanki , Y. C. Unruh , J. Morrill

The space missions MOST, COROT and Kepler are going to provide us with high-precision optical photometry of solar-like stars with time series extending from tens of days to several years. They can be modelled to obtain information on…

Astrophysics · Physics 2008-11-26 A. F. Lanza , A. S. Bonomo , M. Rodono'
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