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Star spot evolution is visible evidence of the emergence/decay of the magnetic field on stellar surface, and it is therefore important for the understanding of the underlying stellar dynamo and consequential stellar flares. In this paper,…

As a planet eclipses its parent star, a dark spot on the surface of the star may be occulted, causing a detectable variation in the light curve. A total of 77 consecutive transit light curves of CoRoT-2 were observed with a high temporal…

Solar and Stellar Astrophysics · Physics 2015-05-14 Adriana Silva-Valio , A. F. Lanza , R. Alonso , P. Barge

Magnetic fields and mass accretion processes create dark and bright spots on the surface of young stars. These spots manifest as surface thermal inhomogeneities, which alter the global temperature measured on the stars. To understand the…

Solar and Stellar Astrophysics · Physics 2022-02-02 C. Flores , M. S. Connelley , B. Reipurth , G. Duchêne

A spectrum of a hot spot, produced by radiation of accretion shock at T Tauri star's surface, has been calculated taking into account non-LTE effects for HeI, HeII, CaI and CaII, using LTE-calculations of spot's atmospheric structure,…

Solar and Stellar Astrophysics · Physics 2015-06-15 A. V. Dodin , S. A. Lamzin , T. M. Sitnova

We assess the impact of starspots on the evolution of late-type stars during the pre-main sequence (pre-MS) using a modified stellar evolution code. We find that heavily spotted models of mass 0.1-1.2\msun\ are inflated by up to $10$%…

Solar and Stellar Astrophysics · Physics 2015-07-15 Garrett Somers , Marc H. Pinsonneault

The spot evolution on the Sun and solar-type stars is important for understanding the nature of consequential flaring activity. This study statistically investigates the variance of flare occurrence rate through the time evolution of spots…

Solar and Stellar Astrophysics · Physics 2025-05-23 Takato Tokuno , Kosuke Namekata , Hiroyuki Maehara , Shin Toriumi

Many active stars are covered in spots, much more so than the Sun, as indicated by spectroscopic and photometric observations. It has been predicted that star spots induce non-zero intrinsic linear polarization by breaking the visible…

Solar and Stellar Astrophysics · Physics 2018-05-16 T. M. Yakobchuk , S. V. Berdyugina

Context. LQ Hya is one of the most frequently studied young solar analogue stars. Recently, it has been observed to show intriguing behaviour by analysing long-term photometry: during 2003--2009, a coherent spot structure migrating in the…

DQ Tau is a young low-mass spectroscopic binary, consisting of two almost equal-mass stars on a 15.8 d period surrounded by a circumbinary disk. Here, we analyze DQ Tau's light curves obtained by Kepler K2, the Spitzer Space Telescope, and…

Solar and Stellar Astrophysics · Physics 2018-08-08 Á. Kóspál , P. Ábrahám , G. Zsidi , K. Vida , R. Szabó , A. Moór , A. Pál

An accurate estimation of the continuum excess emission from accretion spots and inner circumstellar disk regions is crucial for a proper derivation of fundamental stellar parameters in accreting systems. However, the presence of starspots…

Solar and Stellar Astrophysics · Physics 2024-11-20 Facundo Pérez Paolino , Jeff Bary , Lynne Hillenbrand , Madison Markham , William Fischer

Detailed studies of the Sun have shown that sunspots and solar flares are closely correlated. Photometric data from Kepler/K2 has allowed similar studies to be carried out on other stars. Here, we utilise TESS photometric 2-min cadence of…

Solar and Stellar Astrophysics · Physics 2019-08-14 L. Doyle , G. Ramsay , J. G. Doyle , K. Wu

We use high accuracy photometric data obtained with the Kepler satellite to monitor the activity modulations of the Kepler-210 planet host star over a time span of more than four years. Following the phenomenology of the star's light curve…

Solar and Stellar Astrophysics · Physics 2016-10-07 P. Ioannidis , J. H. M. M. Schmitt

We present a reference study of the long-term optical variability of young stars using data from the WASP project. Our primary sample is a group of well-studied classical T Tauri stars (CTTS), mostly in Taurus-Auriga. WASP lightcurves cover…

Solar and Stellar Astrophysics · Physics 2017-01-11 Laura Rigon , Aleks Scholz , David Anderson , Richard West

FU Tau A is a young very low mass object in the Taurus star forming region which was previously found to have strong X-ray emission and to be anomalously bright for its spectral type. In this study we discuss these characteristics using new…

We performed simple spot-model calculations for quasi-periodic brightness variations of solar-type stars showing superflares, by using Kepler photometric data. Most of superflare stars show quasi-periodic brightness modulations with the…

Aims: We carried out high-resolution spectroscopy and BV(I)_C photometric monitoring of the two fastest late-type rotators in the nearby Beta Pictoris moving group, HD199143 (F7V) and CD-641208 (K7V). The motivation for this work is to…

Solar and Stellar Astrophysics · Physics 2015-05-28 D. Garcia-Alvarez , A. F. Lanza , S. Messina , J. J. Drake , F. van Wyk , R. R. Shobbrook , C. J. Butler , D. Kilkenny , J. G. Doyle , V. L. Kashyap

T Tauri stars exhibit variability on all timescales, whose origin is still debated. On WTTS the variability is fairly simple and attributed to long-lived, ubiquitous cool spots. We investigate the long term variability of WTTS, extending up…

Astrophysics · Physics 2009-11-13 K. N. Grankin , J. Bouvier , W. Herbst , S. Yu. Melnikov

To accurately measure a star's atmospheric parameters and chemical abundances, it is crucial to have high-quality spectra. Analysing the detailed chemical abundances of groups of stars can help us better understand nucleosynthesis, galactic…

Solar and Stellar Astrophysics · Physics 2023-07-05 Tanner A. Wilson , Andrew R. Casey

Using the wealth of ~24 yr multiband data, we present an in-depth study of the star-spot cycles, surface differential rotations (SDR), optical flares, evolution of star-spot distributions, and coronal activities on the surface of young,…

Solar and Stellar Astrophysics · Physics 2016-08-24 Subhajeet Karmakar , J. C. Pandey , I. S. Savanov , G. Taş , S. B. Pandey , K. Misra , S. Joshi , E. S. Dmitrienko , T. Sakamoto , N. Gehrels , T. Okajima

Planet formation is one explanation for the partial clearing of dust observed in the disks of some T Tauri stars. Indeed studies using state-of-the-art high angular resolution techniques have very recently begun to observe planetary…

Solar and Stellar Astrophysics · Physics 2015-04-21 E. T. Whelan , N. Huelamo , J. M. Alcala , J. Lillo-Box , H. Bouy , D. Barrado , J. Bouvier , B. Merin