Publications (107)
The mass-radius relation of intermediate-mass planets outlined by hydrodynamic escape and thermal evolution
Daria Kubyshkina, Luca Fossati
We employ planetary evolution modeling to reproduce the MR distribution of the 198 so far detected planets with mass and radius measured to the <45% and <15% level, respectively, a…
An ablating super-Earth in an eccentric binary from the Dispersed Matter Planet Project
John R. Barnes, Carole A. Haswell, Daniel Staab +8
Earth mass exoplanets are difficult to detect. The Dispersed Matter Planet Project (DMPP) identifies stars which are likely to host the most detectable low mass exoplanets. The sta…
Tracing early stellar evolution with asteroseismology: pre-main sequence stars in NGC 2264
Konstanze Zwintz, Luca Fossati, Tatiana Ryabchikova +2
Asteroseismology has been proven to be a successful tool to unravel details of the internal structure for different types of stars in various stages of their main sequence and post…
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…
Understanding Exoplanet Atmospheres with UV Observations II: The Far UV and Atmospheric Escape
Eric D. Lopez, Vladimir Airapetian, Jessie Christiansen +2
Much of the focus of exoplanet atmosphere analysis in the coming decade will be at infrared wavelengths, with the planned launches of the James Webb Space Telescope (JWST) and the…
TESS delivers its first Earth-sized planet and a warm sub-Neptune
Diana Dragomir, Johanna Teske, Maximilian N. Gunther +48
The future of exoplanet science is bright, as TESS once again demonstrates with the discovery of its longest-period confirmed planet to date. We hereby present HD 21749b (TOI 186.0…
Chemical composition of A and F dwarfs members of the Hyades open cluster
M. Gebran, M. Vick, R. Monier +1
Abundances of 15 chemical elements have been derived for 28 F and 16 A stars members of the Hyades open cluster in order to set constraints on self-consistent evolutionary models i…
The Tartu Observatory Fiber-fed Echelle Spectrograph (TOFES) Data Reduction Pipeline
Sandipan P. D. Borthakur, Tõnis Eenmäe, Nikolai Piskunov +9
We introduce the data reduction pipeline for the Tartu Observatory Fiber-fed Echelle Spectrograph (TOFES). TOFES is installed in the Coudé room and will be connected to the 1.5 m…
The importance of non-photon noise in stellar spectropolarimetry. The spurious detection of a non-existing magnetic field in the A0 supergiant HD 92207
Stefano Bagnulo, Luca Fossati, Oleg Kochukhov +1
The low-resolution, Cassegrain mounted, FORS spectropolarimeter of the ESO Very Large Telescope is being extensively used for magnetic field surveys. Some of the new discoveries su…
Transit detection of the long-period volatile-rich super-Earth Lupi d with
Laetitia Delrez, David Ehrenreich, Yann Alibert +75
Exoplanets transiting bright nearby stars are key objects for advancing our knowledge of planetary formation and evolution. The wealth of photons from the host star gives detailed…
An In-Depth Spectroscopic Analysis of the Blazhko Star RR Lyr. I. Characterisation of the star: abundance analysis and fundamental parameters
Katrien Kolenberg, Luca Fossati, Denis Shulyak +4
The knowledge of accurate stellar parameters is a keystone in several fields of stellar astrophysics, such as asteroseismology and stellar evolution. Although the fundamental param…
Far-Ultraviolet Activity Levels of F, G, K, and M dwarf Exoplanet Host Stars
Kevin France, Nicole Arulanantham, Luca Fossati +4
We present a survey of far-ultraviolet (FUV; 1150 - 1450 Ang) emission line spectra from 71 planet-hosting and 33 non-planet-hosting F, G, K, and M dwarfs with the goals of charact…
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…
Close-in sub-Neptunes reveal the past rotation history of their host stars: atmospheric evolution of planets in the HD3167 and K2-32 planetary systems
Daria Kubyshkina, Patricio Cubillos, Luca Fossati +7
Planet atmospheric escape induced by high-energy stellar irradiation is a key phenomenon shaping the structure and evolution of planetary atmospheres. Therefore, the present-day pr…
The GAPS Programme at TNG XXXIX -- Multiple molecular species in the atmosphere of the warm giant planet WASP-80 b unveiled at high resolution with GIANO-B
Ilaria Carleo, Paolo Giacobbe, Gloria Guilluy +28
Detections of molecules in the atmosphere of gas giant exoplanets allow us to investigate the physico-chemical properties of the atmospheres. Their inferred chemical composition is…
Metallicity dependence of turbulent pressure and macroturbulence in stellar envelopes
Luca Grassitelli, Luca Fossati, Norbert Langer +3
Macroturbulence, introduced as a fudge to reproduce the width and shape of stellar absorption lines, reflects gas motions in stellar atmospheres. While in cool stars, it is thought…
High-resolution Ultraviolet-to-nearinfrared Characterization of Exoplanet Atmospheres
Patricio E. Cubillos, Matteo Brogi, Antonio GarcÃa Muñoz +19
The Habitable Worlds Observatory (HWO) offers a unique opportunity to revolutionize our understanding of planetary formation and evolution. The goal of this Science Case Developmen…
The Autonomous Data Reduction Pipeline for the CUTE Mission
A. G. Sreejith, Luca Fossati, S. Ambily +8
The Colorado Ultraviolet Transit Experiment (CUTE) is a 6U NASA CubeSat carrying on-board a low-resolution, near-ultraviolet (2479-3306 A) spectrograph. It has a Cassegrain telesco…
GAUFRE: a tool for an automated determination of atmospheric parameters from spectroscopy
Marica Valentini, Thierry Morel, Andrea Miglio +2
We present an automated tool for measuring atmospheric parameters (T_eff, log(g), [Fe/H]) for F-G-K dwarf and giant stars. The tool, called GAUFRE, is written in C++ and composed o…
TESS and CHEOPS Discover Two Warm Sub-Neptunes Transiting the Bright K-dwarf HD 15906
Amy Tuson, Didier Queloz, Hugh P. Osborn +119
We report the discovery of two warm sub-Neptunes transiting the bright (G = 9.5 mag) K-dwarf HD 15906 (TOI 461, TIC 4646810). This star was observed by the Transiting Exoplanet Sur…
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…
Confronting uncertainties in stellar physics: calibrating convective overshooting with eclipsing binaries
Richard J. Stancliffe, Luca Fossati, Jean-Claude Passy +1
As part of a larger program aimed at better quantifying the uncertainties in stellar computations, we attempt to calibrate the extent of convective overshooting in low to intermedi…
Overcoming the limitations of the energy-limited approximation for planet atmospheric escape
Daria Kubyshkina, Luca Fossati, Nikolay V. Erkaev +6
Studies of planetary atmospheric composition, variability, and evolution require appropriate theoretical and numerical tools to estimate key atmospheric parameters, among which the…
Grid-based exoplanet atmospheric mass loss predictions through neural network
Amit Reza, Daria Kubyshkina, Luca Fossati +1
The fast and accurate estimation of planetary mass-loss rates is critical for planet population and evolution modelling. We use machine learning (ML) for fast interpolation across…
Exoplanet Atmospheric Escape Observations with the Habitable Worlds Observatory
Leonardo A. Dos Santos, Eric D. Lopez, Luca Fossati +15
The Decadal Survey on Astronomy and Astrophysics 2020 highlights the importance of advancing research focused on discovering and characterizing habitable worlds. In line with this…
Company for the ultra-high density, ultra-short period sub-Earth GJ 367 b: discovery of two additional low-mass planets at 11.5 and 34 days
Elisa Goffo, Davide Gandolfi, Jo Ann Egger +38
GJ 367 is a bright (V 10.2) M1 V star that has been recently found to host a transiting ultra-short period sub-Earth on a 7.7 hr orbit. With the aim of improving the plan…
The transiting multi-planet system HD3167: a 5.7 MEarth Super-Earth and a 8.3 MEarth mini-Neptune
Davide Gandolfi, Oscar Barragán, Artie P. Hatzes +42
HD3167 is a bright (V=8.9 mag) K0V star observed by the NASA's K2 space mission during its Campaign 8. It has been recently found to host two small transiting planets, namely, HD31…
TOI-836: A super-Earth and mini-Neptune transiting a nearby K-dwarf
Faith Hawthorn, Daniel Bayliss, Thomas G. Wilson +137
We present the discovery of two exoplanets transiting TOI-836 (TIC 440887364) using data from TESS Sector 11 and Sector 38. TOI-836 is a bright ( mag), high proper motion…
The CHEOPS mission
Willy Benz, Christopher Broeg, Andrea Fortier +107
The CHaracterising ExOPlanet Satellite (CHEOPS) was selected in 2012, as the first small mission in the ESA Science Programme and successfully launched in December 2019. CHEOPS is…
An Overabundance of Low-density Neptune-like Planets
Patricio Cubillos, Nikolai V. Erkaev, Ines Juvan +6
We present a uniform analysis of the atmospheric escape rate of Neptune-like planets with estimated radius and mass (restricted to ). For each planet we c…
CUTE reveals escaping metals in the upper atmosphere of the ultra-hot Jupiter WASP-189b
A. G. Sreejith, Kevin France, Luca Fossati +12
Ultraviolet observations of Ultra-hot Jupiters (UHJs), exoplanets with temperatures over 2000\,K, provide us with an opportunity to investigate if and how atmospheric escape shapes…
A critical assessment of the applicability of the energy-limited approximation for estimating exoplanetary mass-loss rates
Andreas F. Krenn, Luca Fossati, Daria Kubyshkina +1
Context: The energy-limited (EL) atmospheric escape approach is used to estimate mass-loss rates for a broad range of planets that host hydrogen-dominated atmospheres as well as fo…
Detection of Ongoing Mass Loss from HD 63433c, a Young Mini Neptune
Michael Zhang, Heather A. Knutson, Lile Wang +9
We detect Lyman absorption from the escaping atmosphere of HD 63433c, a , d mini Neptune orbiting a young (440 Myr) solar analogue in the Ursa Major…
Pollux: decisions affecting the optical architecture of a high-resolution spectrograph and polarimeter for the Habitable Worlds Observatory
Eduard Muslimov, Luca Fossati, Coralie Neiner +5
POLLUX is a candidate European instrumental contribution to the Habitable Worlds Observatory. It is a high-resolution spectrograph with polarimetric capabilities, covering from the…
ExoGemS High-Resolution Transmission Spectroscopy of WASP-76b with GRACES
Emily K. Deibert, Ernst J. W. de Mooij, Ray Jayawardhana +9
We present high-resolution transmission spectroscopy of WASP-76b with GRACES/Gemini North obtained as part of the ExoGemS survey. With a broad spectral range of 400-1050 nm and a r…
Pollux: high-resolution precision spectroscopy and polarimetry for the Habitable Worlds Observatory
David Le Mignant, Coralie Neiner, Jean-Claude Bouret +10
Pollux is a high-resolution spectrograph and spectropolarimeter (R from 65000 to 100000) covering a spectral range from 100 nm to 1750 nm, proposed by a European consortium to equi…
An Ultra-Short Period Super-Earth and a Sub-Neptune Orbiting the K dwarf TOI-4311
Yoshi Nike Emilia Eschen, Thomas G. Wilson, Andrew Collier Cameron +95
We report the discovery and characterisation of the multi-planetary system around TOI-4311, a K dwarf kinematically between the Galactic thick disk and Hercules stream. TOI-4311 ho…
The Role of N2 as a Geo-Biosignature for the Detection and Characterization of Earth-like Habitats
Helmut Lammer, Laurenz SproÃ, John Lee Grenfell +4
Since the Archean, N2 has been a major atmospheric constituent in Earth's atmosphere. Nitrogen is an essential element in the building blocks of life, therefore the geobiological n…
Uncovering the true periods of the young sub-Neptunes orbiting TOI-2076
Hugh P. Osborn, Andrea Bonfanti, Davide Gandolfi +93
Context: TOI-2076 is a transiting three-planet system of sub-Neptunes orbiting a bright (G = 8.9 mag), young ( Myr) K-type star. Although a validated planetary system, th…
Detecting volcanically produced tori along orbits of exoplanets using UV spectroscopy
Kristina G. Kislyakova, Luca Fossati, Denis Shulyak +17
We suggest to use the Hubble Space Telescople (HST) follow-up observations of the TESS targets for detecting possible plasma tori along the orbits of exoplanets orbiting M dwarfs.…
A grid of upper atmosphere models for 1--40 MEARTH planets: application to CoRoT-7 b and HD219134 b,c
Daria Kubyshkina, Luca Fossati, Nicolay V. Erkaev +5
There is growing observational and theoretical evidence suggesting that atmospheric escape is a key driver of planetary evolution. Commonly, planetary evolution models employ simpl…
The multi-planet system TOI-421 -- A warm Neptune and a super puffy mini-Neptune transiting a G9 V star in a visual binary
Ilaria Carleo, Davide Gandolfi, Oscar Barragán +110
We report the discovery of a warm Neptune and a hot sub-Neptune transiting TOI-421 (BD-14 1137, TIC 94986319), a bright (V=9.9) G9 dwarf star in a visual binary system observed by…
A pair of Sub-Neptunes transiting the bright K-dwarf TOI-1064 characterised with CHEOPS
Thomas G. Wilson, Elisa Goffo, Yann Alibert +132
We report the discovery and characterisation of a pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 (TIC 79748331), initially detected in TESS photometry. To characterise…
Detection of Fe I in the atmosphere of the ultra-hot Jupiter WASP-121b, and a new likelihood-based approach for Doppler-resolved spectroscopy
Neale P. Gibson, Stephanie Merritt, Stevanus K. Nugroho +10
High-resolution Doppler-resolved spectroscopy has opened up a new window into the atmospheres of both transiting and non-transiting exoplanets. Here, we present VLT/UVES observatio…
Effects of Charge Exchange on the Evaporative Wind of HD 209458b
Alex Debrecht, Jonathan Carroll-Nellenback, Adam Frank +4
The role of charge exchange in shaping exoplanet photoevaporation remains a topic of contention. Exchange of electrons between stellar wind protons from the exoplanet's host star a…
The Transiting Multi-planet System HD15337: Two Nearly Equal-mass Planets Straddling the Radius Gap
Davide Gandolfi, Luca Fossati, John H. Livingston +53
We report the discovery of a super-Earth and a sub-Neptune transiting the star HD 15337 (TOI-402, TIC 120896927), a bright (V=9) K1 dwarf observed by the Transiting Exoplanet Surve…
Is pi Men c's atmosphere hydrogen-dominated? Insights from a non-detecton of Hy Ly-alpha absorption
Antonio GarcÃa Muñoz, Allison Youngblood, Luca Fossati +3
Constraining the composition of super-Earth-to-sub-Neptune-size planets is a priority to understand the processes of planetary formation and evolution. pi Men c represents a unique…
Understanding Exoplanet Atmospheres with UV Observations I: NUV and Blue/Optical
Jessie L. Christiansen, Thomas Barclay, Luca Fossati +6
Much of the focus of exoplanet atmosphere analysis in the coming decade will be atinfrared wavelengths, with the planned launches of the James Webb Space Telescope (JWST) and the W…
In-situ observations of resident space objects with the CHEOPS space telescope
Nicolas Billot, Stephan Hellmich, Willy Benz +80
The CHaracterising ExOPlanet Satellite (CHEOPS) is a partnership between the European Space Agency and Switzerland with important contributions by 10 additional ESA member States.…
An Adolescent and Near-Resonant Planetary System Near the End of Photoevaporation
Mu-Tian Wang, Fei Dai, Hui-Gen Liu +28
Young exoplanets provide vital insights into the early dynamical and atmospheric evolution of planetary systems. Many multi-planet systems younger than 100 Myr exhibit mean-motion…
The Hubble/STIS Near-ultraviolet Transmission Spectrum of HD 189733b
Patricio E. Cubillos, Luca Fossati, Tommi Koskinen +5
The benchmark hot Jupiter HD 189733b has been a key target to lay out the foundations of comparative planetology for giant exoplanets. As such, HD 189733b has been extensively stud…
EUV influences on exoplanet atmospheric stability and evolution
Allison Youngblood, Kevin France, Tommi Koskinen +15
The planetary effective surface temperature alone is insufficient to characterize exoplanet atmospheres and their stability or evolution. Considering the star-planet system as a wh…
Optical design and polarimetric performance of a SmallSat UV polarimeter to study interstellar dust: PUFFINS
Ramya M Anche, Hyukmo Kang, Kyle Van Gorkom +19
The Polarimetry in the Ultraviolet to Find Features in INterStellar dust (PUFFINS) is a SmallSat mission concept designed to obtain ultraviolet (UV) spectropolarimetric observation…
Five carbon- and nitrogen-bearing species in a hot giant planet's atmosphere
Paolo Giacobbe, Matteo Brogi, Siddharth Gandhi +40
The atmospheres of gaseous giant exoplanets orbiting close to their parent stars (hot Jupiters) have been probed for nearly two decades. They allow us to investigate the chemical a…
The ocean worlds science case for the Pollux spectropolarimeter
Vincent Hue, Bilal Benmahi, Mathieu Barthelemy +9
Pollux is a candidate European instrument contribution to the Habitable Worlds Observatory (HWO), designed to advance our understanding of the formation and evolution of cosmic str…
EUV observations of cool dwarf stars
Allison Youngblood, Jeremy Drake, James Mason +15
The EUV (100-912 Ã ) is a spectral region notoriously difficult to observe due to attenuation by neutral hydrogen gas in the interstellar medium. Despite this, hundreds to thousand…
Mass Loss from the Exoplanet WASP-12b Inferred from Phase Curves
Taylor J. Bell, Michael Zhang, Patricio E. Cubillos +12
The exoplanet WASP-12b is the prototype for the emerging class of ultra-hot, Jupiter-mass exoplanets. Past models have predicted---and near ultra-violet observations have shown---t…
Characterizing the Habitable Zones of Exoplanetary Systems with a Large Ultraviolet/Visible/Near-IR Space Observatory
Kevin France, Evgenya Shkolnik, Jeffrey Linsky +32
Understanding the surface and atmospheric conditions of Earth-size, rocky planets in the habitable zones (HZs) of low-mass stars is currently one of the greatest astronomical endea…
Dispersed Matter Planet Project Discoveries of Ablating Planets Orbiting Nearby Bright Stars
Carole A. Haswell, Daniel Staab, John R. Barnes +6
Some highly irradiated close-in exoplanets orbit stars showing anomalously low stellar chromospheric emission. We attribute this to absorption by circumstellar gas replenished by m…
An Ultra-Short Period Super-Earth and Sub-Neptune Spanning the Radius Valley Orbiting the Kinematic Thick Disk Star TOI-2345
Yoshi Nike Emilia Eschen, Thomas G. Wilson, Andrea Bonfanti +94
A crucial chemical link between stars and their orbiting exoplanets is thought to exist. If universal, this connection could affect the formation and evolution of all planets. Ther…
Stellar Physics with High-Resolution UV Spectropolarimetry
Julien Morin, Jean-Claude Bouret, Coralie Neiner +26
Current burning issues in stellar physics, for both hot and cool stars, concern their magnetism. In hot stars, stable magnetic fields of fossil origin impact their stellar structur…
Chemical composition of intermediate mass stars members of the M6 (NGC 6405) open cluster
Tolgahan KılıçoÄlu, Richard Monier, Jacques Richer +2
We present here the first abundance analysis of 44 late B, A and F-type members of the young open cluster M6 (NGC 6405, age about 75 Myrs). Spectra, covering the 4500 to 5800 Ã wav…
Detection of ionized calcium in the atmosphere of the ultra-hot Jupiter KELT-9b
Jake D. Turner, Ernst J. W. de Mooij, Ray Jayawardhana +6
With a day-side temperature in excess of 4500K, comparable to a mid-K-type star, KELT-9b is the hottest planet known. Its extreme temperature makes KELT-9b a particularly interesti…
Precise photoionisation treatment and hydrodynamic effects in atmospheric modelling of warm and hot Neptunes
Daria Kubyshkina, Luca Fossati, Nikolai V. Erkaev
Observational breakthroughs in the exoplanet field of the last decade motivated the development of numerous theoretical models describing atmospheres and mass loss, which is believ…
Discovery of magnetic A supergiants: the descendants of magnetic main sequence B stars
Coralie Neiner, Mary E. Oksala, Cyril Georgy +8
In the context of the high resolution, high signal-to-noise ratio, high sensitivity, spectropolarimetric survey BritePol, which complements observations by the BRITE constellation…
Extending a grid of hydrodynamic planetary upper atmosphere models
Daria Kubyshkina, Luca Fossati
In this research note, we outline the extension of the grid of upper atmosphere models first presented in Kubyshkina et al. (2018a). The original grid is based on a 1D hydrodynamic…
CUTE Data Simulator and Reduction Pipeline
A. G. Sreejith, Luca Fossati, Manfred Steller +2
The Colorado Ultraviolet Transit Experiment (CUTE) is a 6U NASA CubeSat carrying a low-resolution (R ~3000), near-ultraviolet (255 - 330nm) spectrograph fed by a rectangular primar…
Rejuvenation of stellar mergers and the origin of magnetic fields in massive stars
Fabian R. N. Schneider, Philipp Podsiadlowski, Norbert Langer +2
Approximately 10% of massive OBA main-sequence (MS) and pre-MS stars harbour strong, large-scale magnetic fields. At the same time there is a dearth of magnetic stars in close bina…
The Colorado Ultraviolet Transit Experiment (CUTE): A dedicated cubesat mission to study exoplanetary mass loss and magnetic fields
Brian T. Fleming, Kevin France, Nicholas Nell +10
The Colorado Ultraviolet Transit Experiment (CUTE) is a near-UV (2550 - 3300 Angstrom) 6U cubesat mission designed to monitor transiting hot Jupiters to quantify their atmospheric…
The Colorado Ultraviolet Transit Experiment (CUTE) Mission Overview
Kevin France, Brian Fleming, Arika Egan +18
Atmospheric escape is a fundamental process that affects the structure, composition, and evolution of many planets. The signatures of escape are detectable on close-in, gaseous exo…
Relating turbulent pressure and macroturbulence across the HR diagram with a possible link to γ-Dor stars
Luca Grassitelli, Luca Fossati, Norbert Langer +3
A significant fraction of the envelope of low- and intermediate-mass stars is unstable to convection, leading to sub-surface turbulent motion. Here, we consider and include the eff…
High-resolution detection of neutral oxygen and non-LTE effects in the atmosphere of KELT-9b
Francesco Borsa, Luca Fossati, Tommi Koskinen +2
Oxygen is a constituent of many of the most abundant molecules detected in exoplanetary atmospheres and a key ingredient for tracking how and where a planet formed. In particular,…
Planetary evolution with atmospheric photoevaporation II: Fitting the slope of the radius valley by combining boil-off and XUV-driven escape
Lukas Affolter, Christoph Mordasini, Apurva V. Oza +2
The Kepler satellite has revealed a gap between sub-Neptunes and super-Earths that atmospheric escape models had predicted as an evaporation valley. We seek to contrast results fro…
Evidence for the volatile-rich composition of a 1.5- planet
Caroline Piaulet, Björn Benneke, Jose M. Almenara +18
The population of planets smaller than approximately is widely interpreted as consisting of rocky worlds, generally referred to as super-Earths. This picture is larg…
Gas-depleted planet formation occurred in the four-planet system around the red dwarf LHS 1903
Thomas G. Wilson, Anna M. Simpson, Andrew Collier Cameron +173
Small exoplanet radii show two populations, referred to as super-Earths and sub-Neptunes, separated by a gap known as the radius valley. This may be produced by the removal of atmo…
Kinetic and photochemical disequilibrium in the potentially carbon-rich atmosphere of the warm-Jupiter WASP-69b
Nidhi Bangera, Christiane Helling, Gloria Guilluy +5
High-resolution transmission spectroscopy of the warm gas-giant WASP-69b has revealed the presence of H2O, CO, CH4, NH3, and C2H2 in its atmosphere. This study investigates the imp…
The Pollux European instrument concept for HWO: a high-resolution spectrograph and spectropolarimeter from the far-UV to the near-IR
Coralie Neiner, Jean-Claude Bouret, Luca Fossati +4
Pollux is a high-resolution spectrograph and spectropolarimeter working from 100 nm to 1.8 microns proposed for HWO by a European consortium. Pollux will allow us to study stellar…
Two Warm Neptunes transiting HIP 9618 revealed by TESS & Cheops
Hugh P. Osborn, Grzegorz Nowak, Guillaume Hébrard +126
HIP 9618 (HD 12572, TOI-1471, TIC 306263608) is a bright ( mag) solar analogue. TESS photometry revealed the star to have two candidate planets with radii of …
Colorado Ultraviolet Transit Experiment Data Simulator
Aickara Gopinathan Sreejith, Luca Fossati, Brian T. Fleming +5
The Colorado Ultraviolet Transit Experiment (CUTE) is a 6U NASA CubeSat carrying on-board a low-resolution (R~2000--3000), near-ultraviolet (2500--3300 Ã ) spectrograph. It has a r…
An Eccentric Sub-Neptune Moving Into the Evaporation Desert
Sydney Jenkins, Andrew Vanderburg, Ritika Sethi +31
Though missions such as Kepler, K2, and TESS have discovered 2,000 sub-Neptune and Neptunian planets, there is a dearth of such planets at close-in (P3 days) orbits. T…
Distance Scale Zero-Points from Galactic RR Lyrae Star Parallaxes
G. Fritz Benedict, Barbara E. McArthur, Michael W. Feast +15
We present new absolute trigonometric parallaxes and proper motions for seven Pop II variable stars: five RR Lyr variables; RZ Cep, XZ Cyg, SU Dra, RR Lyr, UV Oct; and two type 2 C…
Identifying rocky planets and water worlds among sub-Neptune-sized exoplanets with the Habitable Worlds Observatory
Renyu Hu, Michiel Min, Max Millar-Blanchaer +15
Astronomers are debating whether the plentiful "sub-Neptune" exoplanets -- worlds a bit larger than Earth but smaller than Neptune -- are predominantly rocky planets, water-rich "o…
Discovery of two warm mini-Neptunes with contrasting densities orbiting the young K3V star TOI-815
Angelica Psaridi, Hugh Osborn, François Bouchy +130
We present the discovery and characterization of two warm mini-Neptunes transiting the K3V star TOI-815 in a K-M binary system. Analysis of the spectra and rotation period reveal i…
The magnetic fields of hot subdwarf stars
John D Landstreet, Stefano Bagnulo, Luca Fossati +2
Detection of magnetic fields has been reported in several sdO and sdB stars. Recent literature has cast doubts on the reliability of most of these detections. We revisit data previ…
Chemical abundance studies of CP stars in open clusters
Luca Fossati
In stellar astrophysics, the study of the atmospheres of early-type stars plays a very special role. The atmospheres of these stars display a variety of different phenomena, such a…
The PLATO Mission
Heike Rauer, Conny Aerts, Juan Cabrera +842
PLATO (PLAnetary Transits and Oscillations of stars) is ESA's M3 mission designed to detect and characterise extrasolar planets and perform asteroseismic monitoring of a large numb…
Detection of Ionized Calcium in the Atmosphere of the Ultra-Hot Jupiter WASP-76b
Emily K. Deibert, Ernst J. W. de Mooij, Ray Jayawardhana +9
Recent observations of the ultra-hot Jupiter WASP-76b have revealed a diversity of atmospheric species. Here we present new high-resolution transit spectroscopy of WASP-76b with GR…
The Heavy Element Enrichment History of the Universe from Neutron Star Mergers with Habitable Worlds Observatory
Eric Burns, Jennifer Andrews, Robert Szabo +23
Understanding where elements were formed has been a key goal in astrophysics for nearly a century, with answers involving cosmology, stellar burning, and cosmic explosions. Since 1…
Abundance analysis of stars hosting gas-rich debris disks
Sandipan P. D. Borthakur, Mihkel Kama, Luca Fossati +4
Accretion from protoplanetary or debris disks can contaminate the stellar photosphere, which is detectable in stars with radiative envelopes due to relatively slower photospheric m…
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 E…
Aerosol Constraints on the Atmosphere of the Hot Saturn-mass planet WASP-49b
Patricio Cubillos, Luca Fossati, Nikolai Erkaev +6
The strong, nearly wavelength-independent absorption cross section of aerosols produces featureless exoplanet transmission spectra, limiting our ability to characterize their atmos…
A multi-wavelength look at the GJ 9827 system -- No evidence of extended atmospheres in GJ 9827 b and d from HST and CARMENES data
Ilaria Carleo, Allison Youngblood, Seth Redfield +18
GJ9827 is a bright star hosting a planetary system with three transiting planets. As a multi-planet system with planets that sprawl within the boundaries of the radius gap between…
Diagnostic of the unstable envelopes of Wolf-Rayet stars
Luca Grassitelli, Andre-Nicolas Chene', Debashis Sanyal +4
The envelopes of stars near the Eddington limit are prone to various instabilities. A high Eddington factor in connection with the Fe opacity peak leads to convective instability,…
The Dispersed Matter Planet Project Sample -- Detection limits, Occurrence Rates and New Planets
Matthew R. Standing, John R. Barnes, Carole A. Haswell +8
DMPP is a radial-velocity survey that aims to detect planets around stars exhibiting anomalous activity signatures, consistent with the presence of close-in evaporating planets. He…
Generation of a Circumstellar Gas Disk by Hot Jupiter WASP-12b
Alex Debrecht, Jonathan Carroll-Nellenback, Adam Frank +3
Observations of transiting extra-solar planets provide rich sources of data for probing the in-system environment. In the WASP-12 system, a broad depression in the usually-bright M…
Near-ultraviolet Transmission Spectroscopy of HD 209458b: Evidence of Ionized Iron Beyond the Planetary Roche Lobe
Patricio E. Cubillos, Luca Fossati, Tommi Koskinen +5
The inflated transiting hot Jupiter HD 209458b is one of the best studied objects since the beginning of exoplanet characterization. Transmission observations of this system betwee…
Observational consequences of turbulent pressure in the envelopes of massive stars
Luca Grassitelli, Luca Fossati, Sergio Simon-Diaz +3
The major mass fraction of the envelope of hot luminous stars is radiatively stable. However, the partial ionisation of hydrogen, helium and iron gives rise to extended sub-surface…
Refractory phosphorus in the HD 100546 protoplanetary disk
Mihkel Kama, Oliver Shorttle, Sandipan P. D. Borthakur +5
The phosphorus budget of planets is intertwined with their formation history and is thought to influence their habitability. The chemical reservoirs and volatile \emph{vs} refracto…
The Colorado Ultraviolet Transit Experiment (CUTE) signal to noise calculator
A. G. Sreejith, Luca Fossati, P. E. Cubillos +3
We present here the signal-to-noise (S/N) calculator developed for the Colorado Ultraviolet Transit Experiment (CUTE) mission. CUTE is a 6U CubeSat operating in the near-ultraviole…
Coupling thermal evolution of planets and hydrodynamic atmospheric escape in MESA
Daria Kubyshkina, Aline A. Vidotto, Luca Fossati +1
The long-term evolution of hydrogen-dominated atmospheres of sub-Neptune-like planets is mostly controlled by two factors: a slow dissipation of the gravitational energy acquired a…