Results 11 to 20 of about 5,920,212 (288)

Is Core Angular Momentum Key to the Giant Dynamo?

open access: yesUniverse, 2022
The pros and cons of core angular momentum dissipation into the convective envelopes of giants as a driver of giant activity is discussed in face of the observational evidence, which points to two ”magnetic strips“, in the HRD, where in the first, at the
Klaus-Peter Schröder   +1 more
doaj   +1 more source

Magnetic Activity of Different Types of Variable Stars Observed by TESS Mission

open access: yesUniverse, 2023
The investigation of the magnetic activity of different types of variable stars holds significant implications for our understanding of the physical processes and evolution of stars.
Ming Zhong   +3 more
doaj   +1 more source

Spots and Flares in Hot Main Sequence Stars Observed by Kepler, K2, and TESS

open access: yesFrontiers in Astronomy and Space Sciences, 2021
About 22,000 Kepler stars, 7,000 K2 stars, and nearly 60,000 TESS stars from sectors 1–24 have been classified according to variability type. A large proportion of stars of all spectral types appear to have periods in their light curves consistent with ...
Luis A. Balona
doaj   +1 more source

A Stringent Test of Magnetic Models of Stellar Evolution

open access: yesGalaxies, 2021
Main-sequence stars with convective envelopes often appear larger and cooler than predicted by standard models of stellar evolution for their measured masses. This is believed to be caused by stellar activity.
Guillermo Torres   +3 more
doaj   +1 more source

Multiverse Predictions for Habitability: Stellar and Atmospheric Habitability

open access: yesUniverse, 2022
Stellar activity and planetary atmospheric properties have the potential to strongly influence habitability. To date, neither have been adequately studied in the multiverse context, so there has been no assessment of how these effects impact the ...
McCullen Sandora   +3 more
doaj   +1 more source

Revisiting the HD 21749 planetary system with stellar activity modelling [PDF]

open access: yes, 2020
HD 21749 is a bright (V = 8.1 mag) K dwarf at 16 pc known to host an inner terrestrial planet HD 21749c as well as an outer sub-Neptune HD 21749b, both delivered by Transiting Exoplanet Survey Satellite (TESS).
Flowers, Erin   +28 more
core   +1 more source

STELLAR ACTIVITY IN THE BROADBAND ULTRAVIOLET [PDF]

open access: yesThe Astronomical Journal, 2011
The completion of the GALEX All-Sky Survey in the ultraviolet allows activity measurements to be acquired for many more stars than is possible with the limited sensitivity of ROSAT or the limited sky coverage of Chandra, XMM, or spectroscopic surveys for line emission in the optical or ultraviolet.
Findeisen, K.   +2 more
openaire   +3 more sources

Radiative Transfer in 3D Model Stellar Atmospheres

open access: yes, 2003
Recently 3D hydrodynamical simulations of stellar surface convection have become feasible thanks to advances in computer technology and efficient numerical algorithms. Available observational diagnostics indicate that these models are highly realistic in
Asplund, Martin,, Collet, Remo,
core   +8 more sources

On the gamma-activity of stellar flares [PDF]

open access: yesSymposium - International Astronomical Union, 1990
The principal possibility of γ-ray manifestation of stellar flares in the framework of pinch-model is shown. Validity of assumption that, γ-bursts are connected with magnetically active dwarfs (MAD) is discussed.
H. A. Harutyunian, V. S. Hayrapetyan
openaire   +1 more source

Exoplanet transit photometry for stellar activity and exomoon research

open access: yes, 2021
Photometry underlies important discoveries in observational astronomy, from the detection of stellar magnetic phenomena unveiling dynamic dynamo processes to the much sought-after identification of exomoons.
Zaleski, Shelley M.
core   +1 more source

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