Kevin France
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View article: The Near-ultraviolet Spectra of FU Orionis Accretion Disks
The Near-ultraviolet Spectra of FU Orionis Accretion Disks Open
We present the results of the first high-sensitivity near-ultraviolet (NUV; 1800–3200 Å) survey of FU Ori objects, using the Hubble Space Telescope STIS spectrograph. We compare new low-resolution spectra for six sources with predictions f…
View article: X-ray and UV Observations of the Young Sun HIP~67522: Evidence of Lyman-alpha Absorption Within the Planetary System
X-ray and UV Observations of the Young Sun HIP~67522: Evidence of Lyman-alpha Absorption Within the Planetary System Open
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 was moderate spectral variability during the observations con…
View article: HWO Target Stars and Systems: A Survey of Archival UV and X-Ray Data
HWO Target Stars and Systems: A Survey of Archival UV and X-Ray Data Open
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 interpreting planetary atmospheres. Using a sample of 98 nearby…
View article: Stellar Library of Differential Emission Measures and Extreme Ultraviolet Spectra: Dwarf Stars Observed by the Extreme Ultraviolet Explorer
Stellar Library of Differential Emission Measures and Extreme Ultraviolet Spectra: Dwarf Stars Observed by the Extreme Ultraviolet Explorer Open
Extreme ultraviolet (EUV; 100–912 Å) photons influence the formation and evolution of planets by ionizing hydrogen and other species, but the EUV radiation of most exoplanet host stars is poorly constrained. This work applies the different…
View article: FUMES. IV. Optical and Far-ultraviolet Spectra of a Flare on the M Dwarf GJ 4334
FUMES. IV. Optical and Far-ultraviolet Spectra of a Flare on the M Dwarf GJ 4334 Open
On 2017 September 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 Å) and the Dual Imaging Spectrograph mounted on the 3.5…
View article: Magnetohydrodynamic simulation assessment of a potential near-ultraviolet early ingress in WASP-189b
Magnetohydrodynamic simulation assessment of a potential near-ultraviolet early ingress in WASP-189b Open
Context . Ultra-hot Jupiters (UHJs) in close orbits around early-type stars provide natural laboratories for studying atmospheric escape and star-planet interactions under extreme irradiation and wind conditions. The near-ultraviolet (NUV)…
View article: Toward a 2D H I Map of the Local Interstellar Medium
Toward a 2D H I Map of the Local Interstellar Medium Open
Obtaining a complete census of gas in the local interstellar medium (<100 pc) is challenging given the limited available tracers of the warm, partially-ionized medium. Medium-to-high resolution UV absorption spectroscopy toward individual …
View article: The SPACE Program
The SPACE Program Open
Sub-Neptune exoplanets are the most abundant type of planet known today. As they do not have a Solar System counterpart, many open questions exist about their composition and formation. Previous spectroscopic studies have ruled out aerosol…
View article: A Semiempirical Estimate of Solar Extreme-ultraviolet Evolution from 10 Myr to 10 Gyr
A Semiempirical Estimate of Solar Extreme-ultraviolet Evolution from 10 Myr to 10 Gyr Open
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 temperatures spanning roughly 10 4 –10 7 K. The EUV stellar spec…
View article: Detecting Stellar Coronal Mass Ejections via Coronal Dimming in the Extreme Ultraviolet
Detecting Stellar Coronal Mass Ejections via Coronal Dimming in the Extreme Ultraviolet Open
Stellar flares and coronal mass ejections (CMEs) can strip planetary atmospheres, reducing the potential habitability of terrestrial planets. While flares have been observed for decades, stellar CMEs remain elusive. Extreme-ultraviolet (EU…
View article: Mapping galactic winds and small-scale structure in the circumgalactic medium with Habitable Worlds Observatory
Mapping galactic winds and small-scale structure in the circumgalactic medium with Habitable Worlds Observatory Open
View article: Conceptual design study of Far UV IFS and HRS on HWO for exoplanets and solar system bodies
Conceptual design study of Far UV IFS and HRS on HWO for exoplanets and solar system bodies Open
Earth-like planets have been detected in the habitable zone of low-mass stars. However, transit spectroscopy requires extremely high precision to observe the thin layer of lower atmosphere of a small terrestrial planet, and at present no a…
View article: Mapping Galactic Winds and Small-scale Structure in the Circumgalactic Medium with Habitable Worlds Observatory
Mapping Galactic Winds and Small-scale Structure in the Circumgalactic Medium with Habitable Worlds Observatory Open
We present a science case for the Habitable Worlds Observatory (HWO) to map the circumgalactic medium (CGM) in emission by targeting ultraviolet emission lines, which trace the 10^4 - 10^6 K gas engaged in the feedback and accretion mechan…
View article: The UV Legacy Library of Young Stars as Essential Standards (ULLYSES) Large Director’s Discretionary Program with Hubble. I. Goals, Design, and Initial Results
The UV Legacy Library of Young Stars as Essential Standards (ULLYSES) Large Director’s Discretionary Program with Hubble. I. Goals, Design, and Initial Results Open
Specifically selected to leverage the unique ultraviolet capabilities of the Hubble Space Telescope, the Hubble Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) is a Director’s Discretionary program of approximate…
View article: Evidence of a Disk Wind Origin for Fluorescent H<sub>2</sub> in Classical T Tauri Stars
Evidence of a Disk Wind Origin for Fluorescent H<sub>2</sub> in Classical T Tauri Stars Open
We use far-ultraviolet spectra of 36 T Tauri stars, predominately from the Hubble Space Telescope (HST) ULLYSES program, to examine the kinematic properties of fluorescent H 2 emission lines for evidence of disk outflows. Leveraging improv…
View article: The Mega-MUSCLES Treasury Survey: X-Ray to Infrared Spectral Energy Distributions of a Representative Sample of M Dwarfs
The Mega-MUSCLES Treasury Survey: X-Ray to Infrared Spectral Energy Distributions of a Representative Sample of M Dwarfs Open
We present 5–1 × 10 7 Å spectral energy distributions (SEDs) for 12 M dwarf stars covering spectral types M0–M8. Our SEDs are provided for community use as a sequel to the Measurements of the Ultraviolet Spectral Characteristics of Low-mas…
View article: The Featherweight Giant: Unraveling the Atmosphere of a 17 Myr Planet with JWST
The Featherweight Giant: Unraveling the Atmosphere of a 17 Myr Planet with JWST Open
The characterization of young planets (<300 Myr) is pivotal for understanding planet formation and evolution. We present the 3–5 μm transmission spectrum of the 17 Myr, Jupiter-size (R ∼10R ⊕) planet, HIP 67522b, observed with JWST NIRSpec…
View article: The Featherweight Giant: Unraveling the Atmosphere of a 17 Myr Planet with JWST
The Featherweight Giant: Unraveling the Atmosphere of a 17 Myr Planet with JWST Open
The characterization of young planets (<300 Myr) is pivotal for understanding planet formation and evolution. We present the 3–5 μ m transmission spectrum of the 17 Myr, Jupiter-size ( R ∼10 R ⊕ ) planet, HIP 67522b, observed with JWST NIR…
View article: Measurement of interstellar extinction for classical T Tauri stars using far-UV H2 line fluxes
Measurement of interstellar extinction for classical T Tauri stars using far-UV H2 line fluxes Open
Understanding the interstellar and potentially circumstellar extinction in the sight lines of classical T Tauri stars is an important ingredient for constructing reliable spectral energy distributions, which catalyze protoplanetary disk ch…
View article: The Mega-MUSCLES Treasury Survey: X-ray to infrared Spectral Energy Distributions of a representative sample of M dwarfs
The Mega-MUSCLES Treasury Survey: X-ray to infrared Spectral Energy Distributions of a representative sample of M dwarfs Open
We present 5-1x10^7 Angstrom spectral energy distributions (SEDs) for twelve M dwarf stars covering spectral types M0-M8. Our SEDs are provided for community use as a sequel to the Measurements of the Ultraviolet Spectral Characteristics o…
View article: Measurement of interstellar extinction for classical T Tauri stars using far-UV H<sub>2</sub> line fluxes
Measurement of interstellar extinction for classical T Tauri stars using far-UV H<sub>2</sub> line fluxes Open
Understanding the interstellar and potentially circumstellar extinction in the sight lines of classical T Tauri stars is an important ingredient for constructing reliable spectral energy distributions, which catalyze protoplanetary disk ch…
View article: A Model of the C iv λ λ1548, 1550 Doublet Line in T Tauri Stars
A Model of the C iv λ λ1548, 1550 Doublet Line in T Tauri Stars Open
The C iv doublet in the UV has long been associated with accretion in T Tauri stars. However, it is still unclear where and how the lines are formed. Here, we present a new C iv line model based on the currently available accretion shock a…
View article: The Featherweight Giant: Unraveling the Atmosphere of a 17 Myr Planet with JWST
The Featherweight Giant: Unraveling the Atmosphere of a 17 Myr Planet with JWST Open
The characterization of young planets (< 300 Myr) is pivotal for understanding planet formation and evolution. We present the 3-5$μ$m transmission spectrum of the 17 Myr, Jupiter-size ($R$ $\sim$10$R_{\oplus}$) planet, HIP 67522 b, observe…
View article: A Far-ultraviolet-detected Accretion Shock at the Star–Disk Boundary of FU Ori
A Far-ultraviolet-detected Accretion Shock at the Star–Disk Boundary of FU Ori Open
FU Ori objects are the most extreme eruptive young stars known. Their 4–5 mag photometric outbursts last for decades and are attributed to a factor of up to 10,000 increase in the stellar accretion rate. The nature of the accretion disk-to…
View article: The Far-ultraviolet Spectrum of FU Ori South
The Far-ultraviolet Spectrum of FU Ori South Open
The eruptive young stellar object FU Ori is the eponym of its variable class. FU Ori stars are known to undergo outbursts with amplitudes of >4 mag in the V band and durations of several decades. Interaction with a binary companion is one …
View article: The FUV Spectrum of FU Ori South
The FUV Spectrum of FU Ori South Open
The eruptive YSO FU Ori is the eponym of its variable class. FU Ori stars are known to undergo outbursts with amplitudes of $>4$ magnitudes in the $V$ band and durations of several decades. Interaction with a binary companion is one propos…
View article: A Model of the C IV $λλ$ 1548, 1550 Doublet Line in T Tauri Stars
A Model of the C IV $λλ$ 1548, 1550 Doublet Line in T Tauri Stars Open
The C IV doublet in the UV has long been associated with accretion in T Tauri stars. However, it is still unclear where and how the lines are formed. Here, we present a new C IV line model based on the currently available accretion shock a…
View article: The assembly, characterization, and performance of SISTINE
The assembly, characterization, and performance of SISTINE Open
The Suborbital Imaging Spectrograph for Transition region Irradiance from\nNearby Exoplanet host stars (SISTINE) is a rocket-borne ultraviolet (UV)\nimaging spectrograph designed to probe the radiation environment of nearby\nstars. SISTINE…
View article: An FUV-detected Accretion Shock at the Star-Disk Boundary of FU Ori
An FUV-detected Accretion Shock at the Star-Disk Boundary of FU Ori Open
FU Ori objects are the most extreme eruptive young stars known. Their 4 to 5 magnitude photometric outbursts last for decades and are attributed to a factor of up to 10,000 increase in the stellar accretion rate. The nature of the accretio…
View article: Ultraviolet Technology To Prepare For The Habitable Worlds Observatory
Ultraviolet Technology To Prepare For The Habitable Worlds Observatory Open
We present here the current state of a collection of promising ultraviolet technologies in preparation for the Habitable Worlds Observatory. Working with experts representing a significant number of groups working in the ultraviolet, we su…