7 papers
Leveraging Impact Parameter to Mitigate the Transit Light Source Effect: Early Insights from TRAPPIST-1
Ana Glidden, Alexander I. Shapiro, Sara Seager +19
Stellar activity complicates exoplanet transmission spectra, particularly for smaller planets around M dwarfs with JWST. The transit light source (TLS) effect, the imprinting of sp…
Simulations of facular magnetic fields on cool stars I: Main sequence stars with solar metallicity
Tanayveer Singh Bhatia, Robert H. Cameron, Sami K. Solanki +4
Stellar convection in the presence of magnetic field affects the emergent intensity, as well as the structure and evolution of cool main-sequence dwarfs. We aim to understand the e…
Molecular hydrogen controls the temperatures of flares on TRAPPIST-1
Alexander I. Shapiro Nadiia Kostogryz Sara Seager Veronika Witzke Julien de Wit Valeriy Vasilyev Astrid M. Veronig Robert Cameron Hardi Peter Sami K. Solanki
Early JWST observations of TRAPPIST-1 have revealed an unexpected puzzle: energetic white-light flares ( erg) reach temperatures of only 3500--4000\,K, ne…
Flares on TRAPPIST-1 reveal the spectrum of magnetic features on its surface
Valeriy Vasilyev, Nadiia Kostogryz, Alexander I. Shapiro +11
TRAPPIST-1 is an M8 dwarf hosting seven known exoplanets and is currently one of the most frequently observed targets of the James Webb Space Telescope (JWST). However, it is notor…
The effect of stellar magnetic activity on measurements of morning and evening asymmetry of planetary terminator
N. Kostogryz, A. I. Shapiro, L. Carone +9
Differences in the ingress and egress shapes of transit light curves can indicate morning-evening temperature contrasts on transiting planets. Here, we pinpoint an alternative mech…
First Calculations of Starspot Spectra based on 3D Radiative Magnetohydrodynamics Simulations
H. N. Smitha, Alexander I. Shapiro, Veronika Witzke +6
Accurate calculations of starspot spectra are essential for multiple applications in astronomy. The current standard is to represent starspot spectra by spectra of stars that are c…