Thomas Widemann
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View article: The Joint ESA-NASA Venus Science Coordination Group (VESCOOR) to support the three Venus Missions
The Joint ESA-NASA Venus Science Coordination Group (VESCOOR) to support the three Venus Missions Open
The selection of three new missions to Venus opens a new era to explore the planet and its evolution: ESA’s EnVision and NASA’s VERITAS and DAVINCI missions plan to observe Venus in the next decade. ESA and NASA established a joint Venus S…
View article: Water and sulfur dioxide thermal mapping on Venus : Long-term monitoring and vertical distribution of SO2 within and above the clouds
Water and sulfur dioxide thermal mapping on Venus : Long-term monitoring and vertical distribution of SO2 within and above the clouds Open
Sulfur and water play a key role in the chemistry, dynamics, and radiative transfer taking place in the atmosphere of Venus. Temporal and local variations in SO2 and HDO, monitored within or above the clouds, can be indicators of photochem…
View article: High-Resolution Transmission Spectroscopy of Venus: A Proxy for Atmospheric Characterization of Earth-Sized Exoplanets
High-Resolution Transmission Spectroscopy of Venus: A Proxy for Atmospheric Characterization of Earth-Sized Exoplanets Open
The great diversity of detected exoplanets offers a wealth of opportunities for atmospheric characterization studies. Transmission spectroscopy has proven effective in probing the chemical composition and dynamics of hot gas giants, and is…
View article: Mapping Venus in Emissivity: The Venus Emissivity Mapper, VenSpec-M on EnVision and VEM on VERITAS missions to Venus
Mapping Venus in Emissivity: The Venus Emissivity Mapper, VenSpec-M on EnVision and VEM on VERITAS missions to Venus Open
Introduction: Understanding Venus’ surface composition and volcanic activity is central to addressing key questions about the planet’s evolution. These characteristics are tied to the degree of planetary differentiation Venus has undergone…
View article: Goals and Structure of Envision’s VenSpec Ground-Based Observations Working Group
Goals and Structure of Envision’s VenSpec Ground-Based Observations Working Group Open
EnVision is an ESA mission to Venus that will orbit Venus in 2034 and aims to provide a holistic view of Earth’s sister planet from its inner core to its upper atmosphere [1]. The mission is developed in partnership with NASA and has scien…
View article: Science objective and status of the EnVision Mission to Venus
Science objective and status of the EnVision Mission to Venus Open
EnVision is the fifth Medium-class mission in ESA’s Science Program, selected in June 2021 and adopted in January 2024. EnVision is an ESA-led mission in partnership with NASA, where NASA provides the Synthetic Aperture Radar payload…
View article: Constraining surface composition and searching for volcanic activity on Venus: Preparing for future emissivity measurements by EnVision's VenSpec-M and VERITAS's VEM instruments
Constraining surface composition and searching for volcanic activity on Venus: Preparing for future emissivity measurements by EnVision's VenSpec-M and VERITAS's VEM instruments Open
Some of the most outstanding questions about the evolution and present-day state of Venus involve the current level of volcanic activity and its surface composition, both directly linked to the amount of differentiation that our neighbor e…
View article: Exploring Emissivity Variations of Venus Analogs Under Simulated Surface Conditions: Insights for VEM and VenSpec-M data Analysis
Exploring Emissivity Variations of Venus Analogs Under Simulated Surface Conditions: Insights for VEM and VenSpec-M data Analysis Open
Surface rocks on Venus are exposed to a dense atmosphere, primarily composed of CO₂ (96.5%) and N₂ (3.5%), with trace amounts of H₂O and sulfur compounds like SO₂ and H₂SO₄, surface temperatures around 4…
View article: Transmission Spectroscopy Along the Transit of Venus: A Proxy for Exoplanets Atmospheric Characterization
Transmission Spectroscopy Along the Transit of Venus: A Proxy for Exoplanets Atmospheric Characterization Open
We present an analysis of high-resolution, near-infrared (NIR) spectra relative to the solar transit of Venus of 5–6 June 2012, as observed with the Facility Infrared Spectropolarimeter (FIRS) at the Dunn Solar Telescope in New Mexico. The…
View article: Transmission Spectroscopy Along the Transit of Venus: A Proxy for Exoplanets Atmospheric Characterization
Transmission Spectroscopy Along the Transit of Venus: A Proxy for Exoplanets Atmospheric Characterization Open
We present an analysis of high-resolution, near-infrared (NIR) spectra relative to the solar transit of Venus of 5-6 June 2012, as observed with the Facility Infrared Spectropolarimeter (FIRS) at the Dunn Solar Telescope in New Mexico. The…
View article: The VenSpec suite on the ESA Envision mission – a holistic investigation of the coupled surface atmosphere system of Venus
The VenSpec suite on the ESA Envision mission – a holistic investigation of the coupled surface atmosphere system of Venus Open
The ESA EnVision mission will determine the nature and current state of Venus' geological evolution and its relationship with the atmosphere, to understand how and why Venus and Earth evolved so differently. Perched at the inner edge of th…
View article: Venus
Venus Open
After decades of relative neglect, interest in Venus surges anew in the planetary science community and the public. New missions are planned and selected, and will pave the way to the decade of Venus, as new observations allow us to uncove…
View article: Science objective and status of the EnVision Mission to Venus
Science objective and status of the EnVision Mission to Venus Open
EnVision is ESA’s next mission to Venus, in partnership with NASA, where NASA provides the Synthetic Aperture Radar payload and mission support. The ESA mission adoption is scheduled for January 2024, and the launch for 2031. The sta…
View article: Ground-based thermal mapping of Venus:  HDO and SO2 monitoring and upper limits of NH3, PH3 and HCN at the cloud top
Ground-based thermal mapping of Venus:  HDO and SO2 monitoring and upper limits of NH3, PH3 and HCN at the cloud top Open
As part of a long-term monitoring program, full disk thermal maps of HDO (near 7 microns) and SO2 (near 7 and 19 microns) have been obtained at the cloud top of Venus in 2023, using the TEXES(Texas Echelon Cross-Echelle Spectrograph) …
View article: Correction to: Venus Evolution Through Time: Key Science Questions, Selected Mission Concepts and Future Investigations
Correction to: Venus Evolution Through Time: Key Science Questions, Selected Mission Concepts and Future Investigations Open
In the original publication, there has been a discrepancy between values mentioned in the text of Sect. 4.3.3 and in Table 1. The corrected version is provided here: Wrong: The gravity field harmonic coefficients up to an average degree st…
View article: EnVision: Understanding Why Earth's Closest Neighbor Is So Different
EnVision: Understanding Why Earth's Closest Neighbor Is So Different Open
International audience
View article: EnVision: a Nominal Science Phase Spanning Six Venus Sidereal Days
EnVision: a Nominal Science Phase Spanning Six Venus Sidereal Days Open
EnVision was selected as ESA’s 5th M-class mission, targeting a launch in the early 2030s. The mission is a partnership between ESA and NASA, where NASA provides the Synthetic Aperture Radar payload. The scientific objective of EnVis…
View article: A sub-Neptune planet around TOI-1695 discovered and characterized with SPIRou and TESS
A sub-Neptune planet around TOI-1695 discovered and characterized with SPIRou and TESS Open
TOI-1695 is a V -mag = 13 M-dwarf star from the northern hemisphere at 45 pc from the Sun, around which a 3.134-day periodic transit signal from a super-Earth candidate was identified in TESS photometry. With a transit depth of 1.3 mmag, t…
View article: EnVision: understanding why our closest neighbour is so different 
EnVision: understanding why our closest neighbour is so different  Open
<p>&#160;</p> <p>EnVision was selected as ESA's 5th Medium-class mission in the Agency's Cosmic Vision plan, targeting a launch in the early 2030s. EnVision's overarching science questions are to explore the full rang…
View article: Ground-based HDO and SO2 thermal mapping on Venus between 2012 and 2022: : An update&#160;
Ground-based HDO and SO2 thermal mapping on Venus between 2012 and 2022: : An update  Open
<p>Since 2012, we have been monitoring SO<sub>2</sub> and H<sub>2</sub>O (using HDO as a proxy) at the cloud top of Venus, using the TEXES high-resolution imaging spectrometer at the NASA InfraRed Telescope Fa…
View article: Reflectivity of Venus’s Dayside Disk During the 2020 Observation Campaign: Outcomes and Future Perspectives
Reflectivity of Venus’s Dayside Disk During the 2020 Observation Campaign: Outcomes and Future Perspectives Open
We performed a unique Venus observation campaign to measure the disk brightness of Venus over a broad range of wavelengths in 2020 August and September. The primary goal of the campaign was to investigate the absorption properties of the u…
View article: Reflectivity of Venus' dayside disk during the 2020 observation campaign: outcomes and future perspectives
Reflectivity of Venus' dayside disk during the 2020 observation campaign: outcomes and future perspectives Open
We performed a unique Venus observation campaign to measure the disk brightness of Venus over a broad range of wavelengths in August and September 2020. The primary goal of the campaign is to investigate the absorption properties of the un…
View article: Ground-based HDO and SO2 thermal mapping on Venus : An update
Ground-based HDO and SO2 thermal mapping on Venus : An update Open
<p>Since 2012, we have been monitoring SO<sub>2</sub> and H<sub>2</sub>O (using HDO as a proxy) at the cloud top of Venus, using the TEXES high-resolution imaging spectrometer at the NASA InfraRed Telescope Fa…
View article: The EnVision Mission to Venus
The EnVision Mission to Venus Open
<p>On June 10, 2021, the European Space Agency (ESA) announced the selection of EnVision as its newest medium-class science mission. EnVision's overarching science questions are to explore the full range of geoscientific processes op…
View article: Observations of the (1-0) band of CO in Venus using VIRTIS-H aboard Venus Express
Observations of the (1-0) band of CO in Venus using VIRTIS-H aboard Venus Express Open
<p><span>We have used infrared spectra of the dark side of Venus, recorded by the VIRTIS-H spectrometer (Drossart et al. Proc. SPIE 5543, 175, 2014) aboard Venus Express (Svedhem et al. JGR 113, E00B33, 2008), to analyze the CO…