88 citations · 497 across the 31 of their papers we have counts for
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KRONOS II: Solar-like Umbra and Penumbra Properties on the Young Sun V1298~Tau
Matthew M. Murphy, Adina D. Feinstein, Meir E. Schochet +14
Transiting exoplanets provide a unique laboratory for studying stellar surface heterogeneities via starspot or facular occultations. When observed at multiple wavelengths, this con…
X-ray and UV Observations of the Young Sun HIP~67522: Evidence of Lyman-alpha Absorption Within the Planetary System
Cynthia S. Froning, Allison Youngblood, David J. Wilson +7
We present ultraviolet (UV) spectroscopy of the 17 Myr, G0V star, HIP 67522. The UV spectrum is characterized by strong chromospheric and transition region emission lines. There wa…
HWO Target Stars and Systems: A Survey of Archival UV and X-ray Data
Sarah Peacock, David J. Wilson, Tyler Richey-Yowell +14
We assess archival high-energy data for key stars on the Habitable Worlds Observatory (HWO) Target Stars and Systems 2025 list, as stellar radiation is critical to shaping and inte…
FUMES IV: Optical and Far-ultraviolet Spectra of a Flare on the M Dwarf GJ 4334
Girish M. Duvvuri, J. Sebastian Pineda, Aylin García Soto +5
On 2017-09-20 we observed GJ 4334, an M5V dwarf rotating with a period of 23.5 days, simultaneously with both the Space Telescope Imaging Spectrograph aboard Hubble (1160 -- 1710 A…
A Semi-Empirical Estimate of Solar EUV Evolution from 10 Myr to 10 Gyr
Kevin France, Girish Duvvuri, Cynthia Froning +9
The extreme-ultraviolet (EUV; 100 -- 911 Å) spectra of F, G, K, and M stars provide diagnostics of the stellar chromosphere through the corona, with line and continuum formation te…
Short-Term Balmer Line Emission Variability in M Dwarfs
Aylin Garcia Soto, Girish M. Duvvuri, Elisabeth R. Newton +3
M Dwarfs make up the majority of stars, offering an avenue for discovering exoplanets due to their smaller sizes. However, their magnetic activity poses challenges for exoplanet de…
The High-Energy Spectrum of the Young Planet Host V1298 Tau
Girish M. Duvvuri, P. Wilson Cauley, Fernando Cruz Aguirre +4
V1298 Tau is a young pre-main sequence star hosting four known exoplanets that are prime targets for transmission spectroscopy with current-generation instruments. This work pieces…
The MUSCLES Extension for Atmospheric and Transmission Spectroscopy: UV and X-ray Host-star Observations for JWST ERS & GTO Targets
Patrick R. Behr, Kevin France, Alexander Brown +8
X-ray through infrared spectral energy distributions (SEDs) are essential for understanding a star's effect on exoplanet atmospheric composition and evolution. We present a catalog…
Coronal X-Ray Emission from Nearby, Low-Mass, Exoplanet Host Stars Observed by the MUSCLES and Mega-MUSCLES HST Treasury Survey Projects
Alexander Brown, P. Christian Schneider, Kevin France +8
The high energy X-ray and ultraviolet (UV) radiation fields of exoplanet host stars play a crucial role in controlling the atmospheric conditions and the potential habitability of…
FUMES III: Ultraviolet and Optical Variability of M Dwarf Chromospheres
Girish M. Duvvuri, J. Sebastian Pineda, Zachory K. Berta-Thompson +2
We obtained ultraviolet and optical spectra for 9 M~dwarfs across a range of rotation periods to determine whether they showed stochastic intrinsic variability distinguishable from…
X-ray Emission from the Exoplanet Hosting LTT 1445 Triple Star System
Alexander Brown, Cynthia S. Froning, Allison Youngblood +5
JWST will be able to observe the atmospheres of rocky planets transiting nearby M dwarfs. The M dwarf triple star system LTT 1445, at a distance of 6.86 pc, hosts some of the neare…
AU Microscopii in the FUV: Observations in Quiescence, During Flares, and Implications for AU Mic b and c
Adina D. Feinstein, Kevin France, Allison Youngblood +13
High energy X-ray and ultraviolet (UV) radiation from young stars impacts planetary atmospheric chemistry and mass loss. The active Myr M dwarf AU Mic hosts two exoplanet…
The Mega-MUSCLES Spectral Energy Distribution Of TRAPPIST-1
David J. Wilson, Cynthia S. Froning, Girish M. Duvvuri +19
We present a 5A-100um Spectral Energy Distribution (SED) of the ultracool dwarf star TRAPPIST-1, obtained as part of the Mega-MUSCLES Treasury Survey. The SED combines ultraviolet…
Reconstructing the Extreme Ultraviolet Emission of Cool Dwarfs Using Differential Emission Measure Polynomials
Girish M. Duvvuri, J. Sebastian Pineda, Zachory K. Berta-Thompson +16
Characterizing the atmospheres of planets orbiting M dwarfs requires understanding the spectral energy distributions of M dwarfs over planetary lifetimes. Surveys like MUSCLES, HAZ…
Characterizing K2 Candidate Planetary Systems Orbiting Low-Mass Stars IV: Updated Properties for 86 Cool Dwarfs Observed During Campaigns 1-17
Courtney D. Dressing, Kevin Hardegree-Ullman, Joshua E. Schlieder +15
We present revised stellar properties for 172 K2 target stars that were identified as possible hosts of transiting planets during Campaigns 1-17. Using medium-resolution near-infra…