42 citations · 207 across the 25 of their papers we have counts for
12 papers · 1 filter
Magnetic Activity as a Driver of Low-gravity-like Spectral Morphology in Late-M Dwarfs
Chia-Lung Lin, Daniel Apai, Benjamin V. Rackham +7
We present a systematic investigation of the connection between magnetic activity and the low-surface-gravity-like near-infrared spectral morphology of late-M dwarfs. Our sample in…
Granulation-driven spectral irradiance variability of Sun-like stars
N. -E. Nèmec, G. Kopp, V. Witzke +1
Granulation,caused by convection in low-mass stars like the Sun, introduces small amplitude variations in the stellar brightness on timescales of minutes to hours. Often referred t…
Granulation in Color: The Chromatic Stellar Flicker of LTT-9779 and WASP-121
William C. Waalkes, Nadiia Kostogryz, Valeriy Vasilyev +9
Granulation is a persistent feature of stars with outer convective layers and is the photospheric signature of near-surface convective energy transport. In disk-integrated observat…
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…
Nautilus: Fast Time-Resolved Spectroscopy of GKM Stellar Flares and Their Implications for Planetary Habitability
Chia-Lung Lin, Adina D. Feinstein, Jeff Valenti +10
Low-mass GKM dwarfs are prime targets for finding habitable-zone Earth-sized planets, but their frequent flares, especially on M~dwarfs, can strongly affect planetary atmospheres t…
Effect of surface magnetic fields on limb darkening in main-sequence stars
N. Kostogryz, A. I. Shapiro, V. Witzke +5
Context.Stellar limb darkening encodes the thermal and radiative structure of stellar photospheres and is a key ingredient in modeling transit light curves and transmission spectra…
The Curious Case of Dark Faculae on M Dwarf Stars
Alexander~I. ~Shapiro, Sara~Seager, Sami~K. ~Solanki +6
The study of exoplanet atmospheres has brought a renewed interest in stellar astrophysics. Specifically, stellar magnetic activity from the host star contaminates exoplanet atmosph…
A Scalable Path to Astrometric Exomoon Discoveries with the Nautilus Space Observatory
Kevin Wagner, Sumin Seung, Dániel Apai +13
Moons orbiting exoplanets (exomoons) can be detected through the reflex motion they impart to their host planet, which is recoverable in relative star-planet astrometric time serie…
A single power law for the TRAPPIST-1 flare distribution across four orders of magnitude in energy
Valeriy Vasilyev, Alexander I. Shapiro, Nadiia Kostogryz +10
TRAPPIST-1 is an ultra-cool dwarf that flares frequently. These flares shape the surrounding planets' high-energy irradiation environments, with consequences for atmospheric chemis…
Sensitivity of spectral lines to granulation: from the Sun to K-type stars
V. Vasilyev, K. Sowmya, A. I. Shapiro +7
Stellar granulation produces radial-velocity (RV) jitter at the 1 m/s level in Sun-like stars, limiting Earth-analog detection. A route beyond this limit is to weight spectral line…
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…