104 citations · 204 across the 18 of their papers we have counts for
18 papers
Understanding the Energy Input Required for Methane Emission on CWISEP J193518.59-154620.3: A Comprehensive Analysis
Kayla J. Smith, Mark S. Marley, Tommi T. Koskinen +1
The Y dwarf WISE 1935 exhibits a thermal inversion in its radiative atmosphere, producing methane emission features in its JWST spectrum, but the physical mechanism responsible for…
ESCAPE: a small explorer mission to study the stellar drivers of exoplanet evolution
Allison Youngblood, Kevin France, Brian Fleming +37
The long-term stability of exoplanetary atmospheres depends critically on the extreme-ultraviolet (EUV) photon and high-energy particle fluxes from the host star, which are poorly…
The role of the Hubble Space Telescope in advancing our understanding of atmospheric escape in exoplanets
Leonardo A. Dos Santos, Arika Egan, Kevin France +14
An important evolutionary pathway for planetary atmospheres is escape to space, which has been studied on Earth and Mars for several decades and more recently in exoplanets. A part…
Helium escape in context: Comparative signatures of four close-in exoplanets
Anna Ruth Taylor, Tommi T. Koskinen, Chenliang Huang +2
Observations of escaping atmospheres on close-in exoplanets show a wide range in the strength and morphology of He I 10830 A and H I absorption. Scaling relations attempt to link t…
HST-COS Transit Spectroscopy of KELT-20b: First Detection of Excess Far-ultraviolet Absorption From an Ultra-hot Jupiter
Patrick R. Behr, Kevin France, Luca Fossati +4
KELT-20 b is an ultra-hot Jupiter with an equilibrium temperature of K orbiting a bright (V =7.6), fast-rotating (=117 km s) A2 V star. The atmosphere of KE…
The Photochemical Plausibility of Warm Exo-Titans Orbiting M-Dwarf Stars
Sukrit Ranjan, Nicholas F. Wogan, Ana Glidden +7
The James Webb Space Telescope (JWST) has begun to spectrally characterize small exoplanets orbiting M-dwarf stars, but interpretation of these spectra is ambiguous, with stellar,…
Toward a 2D H I Map of the Local Interstellar Medium
Allison Youngblood, Kevin France, Tommi Koskinen +9
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-hi…
A Multi-Species Atmospheric Escape Model with Excited Hydrogen and Helium: Application to HD209458b
Anna Ruth Taylor, Tommi T. Koskinen, Luca Argenti +4
Atmospheric escape shapes exoplanet evolution and star-planet interactions, with He I 10830 Å absorption serving as a key tracer of mass loss in hot gas giants. However, transit de…
Signatures of Atmospheric Mass Loss and Planet Migration in the Time Evolution of Short-Period Transiting Exoplanets
Rachel B. Fernandes, Galen J. Bergsten, Gijs D. Mulders +19
Comparative studies of young and old exoplanet populations offer a glimpse into how planets may form and evolve with time. We present an occurrence rate study of short-period (1…
Colorado Ultraviolet Transit Experiment Near-Ultraviolet Transmission Spectroscopy of the Ultra-hot Jupiter KELT-9b
Arika Egan, Kevin France, Aickara Gopinathan Sreejith +9
We present new near-ultraviolet (NUV, = 2479 3306 ) transmission spectroscopy of KELT-9b, the hottest known exoplanet, obtained with the Colorado Ultraviolet Transit Exp…
Seasonal variation of Saturn's Lyman- brightness
P. Stephenson, T. T. Koskinen, Z. Brown +5
We examine Saturn's non-auroral (dayglow) emissions at Lyman- observed by the {Cassini/UVIS} instrument from 2004 until 2016, to constrain meridional and seasonal trends in the…
A pole-to-pole map of hydrocarbons in Saturn's upper stratosphere and mesosphere
Zarah L. Brown, Tommi T. Koskinen, Julianne I. Moses +1
We analyze data from the final two years of the Cassini mission to retrieve the distributions of methane, ethane, acetylene, ethylene, and benzene in Saturn's upper stratosphere an…
Saturn's Seasonal Atmosphere at Northern Summer Solstice
L. N. Fletcher, L. Sromovsky, V. Hue +4
The incredible longevity of Cassini's orbital mission at Saturn has provided the most comprehensive exploration of a seasonal giant planet to date. This review explores Saturn's ch…
Non-Local Thermodynamic Equilibrium Transmission Spectrum Modelling of HD209458b
Mitchell E. Young, Luca Fossati, Tommi T. Koskinen +3
Context - Exoplanetary upper atmospheres are low density environments where radiative processes can compete with collisional ones and introduce non-local thermodynamic equilibrium…
Effect of stellar flares on the upper atmospheres of HD 189733b and HD 209458b
J. M. Chadney, T. T. Koskinen, M. Galand +2
Stellar flares are a frequent occurrence on young low-mass stars around which many detected exoplanets orbit. Flares are energetic, impulsive events, and their impact on exoplaneta…
Far-UV spectroscopy of the planet-hosting star WASP-13: high-energy irradiance, distance, age, planetary mass-loss rate, and circumstellar environment
L. Fossati, K. France, T. Koskinen +3
Several transiting hot Jupiters orbit relatively inactive main-sequence stars. For some of those, the logR'HK activity parameter lies below the basal level (-5.1). Two explanations…
Characterizing the thermosphere of HD209458b with UV transit observations
T. T. Koskinen, R. V. Yelle, P. Lavvas +1
Transmission spectroscopy at UV wavelengths is a rich and largely unexplored source of information about the upper atmospheres of extrasolar planets. So far, UV transit observation…
The Upper Atmosphere of HD17156b
T. T. Koskinen, A. D. Aylward, S. Miller
HD17156b is a newly-found transiting extrasolar giant planet (EGP) that orbits its G-type host star in a highly eccentric orbit (e~0.67) with an orbital semi-major axis of 0.16 AU.…