ESA's Holland-Area Exoplanet Science Meeting (HAESM) 2025

Uniting all ESA and Holland-area exoplaneteers for a day of science, discussions, and collaboration; our colleagues from ESAC, STScI, and external institutions are equally encouraged to join us remotely.
Tuesday, 1 April 2025, 13:00 - 17:30 CEST, in ESTEC and online (via WebEx).​​​​​​

Programme

Local information

Arrival and social programme: All in-person attendees are invited to arrive at the ESTEC security gatehouse (Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands) at 11:00 CEST. You must bring your passport with you to collect your scientific visitor badges for the day. You can reach ESTEC by bicycle or local bus systems (e.g. from Leiden Centraal); for your individual travel planning please consult an online map service. Our colleagues from security and our friendly helpers will receive you and guide you from there to our ESTEC cafeteria, where we can enjoy a coffee and lunch (self-paid). The science programme starts from 13:00 CEST, with a mix of in-person and virtual presentations. Of course, we have planned for ample room for networking and exchange during two complementary coffee breaks. Finally, we hope to enjoy a relaxing evening in the Dutch Sun and continue with informal science discussions during a borrel at the ESCAPE lounge from around 17:30 CEST.

Meeting rooms: We have booked a group of our most modern meeting rooms, surrounding our complementary coffee corner. No worries, we will guide you there. For reference, these are called Ocean 1, Land 2, Atmosphere 1, and Atmosphere 2.

WebEx: The meeting and all presentations will happen in WebEx. If you are not familiar with WebEx, please ask for a short test session before the meeting starts. If it is your first time using WebEx, you will usually have to adjust a couple of system settings and restart the software or your whole computer. The WebEx link is shared via email.

Abstracts

How to observe with CHEOPS (Bruno Merín, ESA)

This talk will illustrate the observing capabilities of the CHEOPS mission, how can they be combined with other facilities and will give you tips on how to improve your chances of getting CHEOPS time for your science projects.

Atmospheric retrievals meet disc modelling: JWST/NIRSpec’s full 0.97–5.27 μm view of young brown dwarfs (Dario Gonzalez Picos, Leiden Observatory)

Space-based infrared spectroscopy with JWST is revolutionising our understanding of substellar atmospheres. Here, we perform detailed atmospheric retrievals on two young brown dwarfs, TWA 27A and TWA 28, utilising JWST/NIRSpec’s full 0.97–5.27 μm coverage at native resolution. This approach enables the simultaneous characterisation of atmospheric and circumstellar emission signals across near- to mid-infrared wavelengths. Our analysis uncovers a rich molecular inventory, including H₂O, CO, CO₂, SiO, metal oxides, hydrides, and atomic species. Notably, we constrain abundances of CO isotopologues and report the first space-based detection of secondary TiO isotopologues—critical tracers of formation and evolution histories. We retrieve temperature structures and radii while constraining the properties of disks through their (i) continuum blackbody emission and (ii) CO line emission tracing warm, dynamically active disk gas. This work establishes JWST as a transformative tool for disentangling the intertwined roles of atmospheres and disks, setting a benchmark for retrievals of young, directly imaged exoplanets.

The cloudy exoplanets with JWST (Quentin Changeat, University of Groningen) 

Hubble Space Telescope (HST) observations provided initial insights into the ubiquitous presence of clouds in exoplanet atmospheres. However, only with the advent of the James Webb Space Telescope (JWST) have we been able to characterize their properties in detail. In this talk, I will explore how next-generation observatories like JWST and Ariel are revolutionizing our understanding of cloudy exoplanets and unlocking new avenues for atmospheric studies.

Self-roast: Close-in planet induces flares on its host star (Ekaterina Ilin, ASTRON)    

In the past decade, hundreds of exoplanets have been discovered in extremely short orbits below 10 days. Unlike in the Solar System, planets in these systems orbit their host stars close enough to disturb the stellar magnetic field lines. The interaction can enhance the star's magnetic activity, such as its chromospheric and radio emission, or flaring. So far, the search for magnetic star-planet interactions has remained inconclusive. In this talk, I present the first detection of planet-induced flares on HIP 67522, a 17 million-year-old G dwarf star with two known close-in planets. Combining space-borne photometry from TESS and dedicated CHEOPS observations over a span of 5 years, we find that the 15 flares in HIP 67522 cluster near the innermost planet's transit phase, indicating persistent magnetic star-planet interaction in the system. The stability of interaction implies that the innermost planet is continuously self-inflicting a six times higher flare rate than it would experience without interaction. The subsequent flux of energetic radiation and particles bombarding HIP 67522 b may explain the planet's remarkably extended atmosphere, recently detected with the James Webb Space Telescope, potentially doubling its mass loss rate. Our results establish HIP 67522 as the archetype system for flaring star-planet interaction, and urge further characterization of the dynamic magnetism of this and similar star-planet systems.

Rocky planet formation around M dwarfs (Mariana Sanchez, Leiden Observatory)

Rocky planets in compact configurations are common around M dwarfs, which often host small, compact disks (typically under 20 au) lacking observable substructures. These compact disks, around very low-mass stars (0.1–0.5 M☉), suggest efficient radial drift, potentially enhancing planet formation in close-in orbits. Using N-body simulations, we examined the formation of close-in rocky planets via pebble and planetesimal accretion. We found that low-viscosity gas disks (α=10⁻⁴) supported the formation of planet populations matching observed exoplanetary masses and semi-major axis. This result points towards a new approach in the direction of the disk conditions needed for rocky planet formation around very low mass stars.

Chemical abundances in nearby Sun-like stars (and in their proto-planetary discs) (Philippe Gondoin, ESA Exoplanet Team) 

Nearby Sun-like stars are prime targets for the detection and characterisation of exo-planets and possibly exo-Earth. Their chemical abundances are an imprint of the interstellar medium composition in the region where they formed at the epoch of their formation. The presentation addresses the evolution of the Milky Way disc composition in the region where nearby Sun-like stars and their planets formed.

Simultaneous Magnetic Mapping of τ Boötis A and Radio Detection in the τ Boötis System (Dag Evensberget, Leiden Observatory)

Recent LOFAR radio observations of the ζ Boötis system have been tentatively attributed to wind–planet interactions between ζ Boötis A and its planet. For the first time, we present a surface magnetic map and stellar wind models derived from contemporaneous spectropolarimetric observations. These wind models allow us to explore the radio emission mechanisms active in the ζ Boötis system at the time of detection. Since exoplanet radio emissions depend critically on both the stellar wind power and the magnetic field geometry of the star–planet system, we develop a fully three-dimensional magnetohydrodynamic model of ζ Boötis A. By applying a moderate scaling to the magnetic field, our model yields wind energy fluxes strong enough to account for the observed radio signals.

Expanding the search of radio exoplanets with LOFAR (Cristina-Maria Cordun, ASTRON)

Gaseous exoplanets generate low-frequency radio emission (<40 MHz), which is associated with aurorae via circularly polarized cyclotron maser mechanism and is directly related to the surrounding space weather. To obtain a detailed analysis of this mechanism, one must measure the stellar wind's electron density and the planet's magnetic field, which is only possible with observations at radio frequencies. Despite many attempts, direct imaging of exoplanets in the radio band has yet to be successful, with only a few tentative detections. This study uses the Low-Frequency Array (LOFAR) to search for such a signal. The primary focus is on Tau Boötis b, currently the most promising candidate for radio emission. Additionally, a new decameter survey (LoDeSS) is used to search for signals from other potential radio-emitting exoplanets. The challenge lies in overcoming high levels of radio interference and the rapidly changing ionospheric conditions that strongly affect observations at these frequencies. By conducting deep observations of Tau Boötis b and expanding the search across multiple candidates, this study aims to bring us closer to detecting radio exoplanets—or to understanding why these signals remain hidden. I will conclude with key lessons learned and an introduction to an ongoing major LOFAR upgrade, which will enhance imaging down to 15 MHz and improve search methods for radio exoplanet detection.

Exploring Archean Earth atmospheres of exomoons around Epsilon Eridani b with ROCKE-3D (Hylke Hoogland, Leiden Observatory)

Given the large number of exoplanets discovered, it is reasonable to assume that exomoons exist too. The properties of exomoons yield insights into the formation of the host system. Compared to exoplanets, tidal heating (due to an eccentric orbit around the host planet) can be a more significant source of energy to the surface of exomoons. This additional heating at the surface may allow exomoons to be habitable at much greater distance from their host star than is the case for exoplanets. In this work we aim to explore possible climate states of hypothetical exomoons around Epsilon Eridani b assuming atmospheres similar to Earth during the archean era.

Data-Intensive Pipeline for Robust Exoplanet Analysis: Application to the Long-Period Exoplanet TOI-4409 b (Patricio Reller, UCL / ESA)

We present a data-intensive pipeline in development to improve the reliability and robustness of exoplanetary analyses. By integrating and comparing different modelling methods, the pipeline refines parameter posterior distributions by addressing the unique assumptions and noise treatments specific to each approach. Its modular design allows specific algorithms and components to be compared in isolation, building on existing pipelines to achieve more precise results. As a proof of concept, we apply this framework to the long-period exoplanet candidate TOI-4409 b, observed across 14 transits by multiple instruments (TESS, ASTEP, CHAT, and OMES). Our combined analysis confirms its presence around the host star and refines its physical characteristics as initially derived from TESS data. We welcome feedback on desired features to optimise the pipeline's usability for diverse research applications.

High five from ASTEP: Validation of four warm Jupiters and one sub-Neptune with long orbital periods    (Erika Rea, ESA)

Most known exoplanets to date are found in short-period orbits due to geometric transit probabilities and observational challenges. Since all-sky surveys like TESS have limited observation windows, we need complementary follow-up missions to detect and understand longer-period exoplanets. The Antarctic Search for Transiting ExoPlanets (ASTEP), located at Dome C, Antarctica, provides a unique advantage for monitoring long-duration transits, benefiting from extended winter darkness from March - September, exceptional atmospheric stability and minimal scintillation noise. This study presents the results of a targeted validation effort for long-period exoplanets, combining ASTEP observations with data from TESS and additional ground-based facilities. We identified five candidates with orbits of 32 - 104 days and radii of 2.4 - 16 REarth, including four warm Jupiters and one sub-Neptune. In particular, TOI-4507.01 and TOI-4404.01 appear to be inflated Jupiters, occupying a previously uncharted region of the period-radius parameter space, where no exoplanets have been confirmed so far. By bridging the gap between short-period exoplanets and the poorly understood population of long-period worlds, this study highlights ASTEP's essential role in expanding the known population of long-period transiting exoplanets, reinforcing the necessity and impact of ground-based, high-precision photometry to complement space-based surveys.

Diving into the atmospheres of young planets through the lens of CHEOPS (Hinna Shivkumar, University of Amsterdam)

Transit surveys have revealed young transiting exoplanets (<200 Myr) that present unique opportunities to study the origins, evolution, and eventual fates of exoplanets in ways that are complementary to their mature counterparts. In order to infer the internal and atmospheric structure of these young, inflated planets, high-precision measurements of their mass and radius are essential. In this talk, I will present high-precision transit observations of planets in a young (~20 Myr) system with CHEOPS. I will also provide a first look at the JWST/CHEOPS simultaneous observations of a planet in a slightly older (~100 Myr) system. Additionally, I will discuss the challenges of addressing and decorrelating stellar variability evident in these observations of young planets. I will also discuss the powerful synergy between CHEOPS and JWST for future observational campaigns.

Two-step registration and abstract submission (Deadline: 14 Mar 2024)

If you would like to join us for HAESM 2025 - whether in person or remotely, whether to network, listen in, or to present your own resarch highlights - please use the form below to start.

Mandatory two-step registration: ESA's on-site security regulations are strict, to say the least. Please submit your step-1 registration and abstract via the form below. You will then receive a confirmation email with a private link to your step-2 registration via a different form. Please complete both steps of the registration as early as possible and no later than Fri, 14 Mar 2025.

Science presentations are forseen to be around 10+5 minutes (talk+questions), but the exact duration might be altered depending on the number of abstracts submitted. HAESM 2025 seeks to give everyone a platform to present their work, and especially encourages contributions from early career scientists. The event also actively encourages any and all "unconference" approaches, and as such the form below is also open to submissions of ideas for group discussions, brainstormings, diversity workshops, and other events that fit the scope.

Personal Data Protection

Please note the following important privacy information related to Science conferences. The full information can be read in the event privacy notice, which must be agreed to as a requirement for participating in the Science conference.

• The event you are registering for may be livestreamed/recorded and you are likely to feature in the video, which may be published on ESA or external web platforms such as YouTube. If you do not wish your personal data to be captured, then you have the right to switch off your camera and microphone, or if attending in person, sit in an area that is not being filmed.
• You accept that ESA has limited control of data published on external web platforms (such as YouTube) and that the use of your data is subject to the privacy policy of the external platform.
• Photographs may be taken at this even by an ESA photographer for published on ESA websites as a historical record of attendance. If you do not wish to have your photograph taken, please inform the event organiser.
• By registering you acknowledge that your personal data may be sent outside of the EU as part of the abstract assessment process. This may include your personal data being sent to countries not qualified by the European Commission as providing an adequate level of protection for personal data. 
• By submitting the personal data of co-authors, you confirm that you have their consent to the event privacy notice. It is the responsibility of the submitter to gather and manage this consent.

Code of Conduct

The European Space Agency (ESA) strives to create a positive work environment where all people are treated with respect and dignity. In the context of ESA Science workshops and conferences, all participants are expected to help create an environment at the meeting and all associated activities that is professional, inclusive, and in which everyone is treated with respect.

All participants are therefore requested to follow these guidelines:

1. All participants are expected to behave professionally and to be respectful – critique ideas not people.
2. All communication should be appropriate for a professional audience taking into account the many different backgrounds and perspectives of the participants.
3. Participants may share the contents of talks/slides via social media unless speakers have asked that specific details/slides not be shared. If participants wish to share photos of a speaker on social media, it is strongly recommended that they first get the speaker’s permission.

ESA does not tolerate unprofessional or inappropriate behaviour or statements. This includes but isn’t limited to: sustained disruption of talks, comments related to individual characteristics, background or identity, and photography or recording of an individual without consent.

Meeting organisers and chairs bear a particular responsibility in ensuring that the code of conduct is followed.

• The Local Organising Committee members are designated as the contact points for all matters related to this code. Participants can report any violation of these guidelines to these designates in confidence.
• Should a participant witness behaviour they suspect may be unprofessional or inappropriate, it is recommended that they approach the affected person as soon as possible to support and help them. The witness can encourage the affected person to report the unprofessional or inappropriate behaviour but should be guided by that person on their preferred course of action.
• Anyone requested to stop inappropriate behaviour is expected to comply immediately. In serious cases, a participant may be asked to leave the event without a refund or, in the case of online participation, the removal of meeting credentials.
• In the case where the unprofessional or inappropriate behaviour involves an ESA staff member, ESA’s Human Resources Department may be contacted for further guidance on the applicable policies and means of action.

Acknowledgments: This code of conduct has been adapted from the London Code of Conduct (by A. Pontzen and H. Peiris), which was derived from original Creative Commons documents by PyCon and Geek Feminism. It is released under a CC-Zero licence for reuse. To help track people's improvements and best practice, please retain this acknowledgement, and log your re-use or modification of this policy at: https://github.com/apontzen/london_cc .

WebEx Etiquette

• Test if you can screenshare well in advance of your scheduled presentation; your computer's privacy settings might ask you to leave and reenter the meeting before you can screenshare
• Your screen name should be your full name followed by your institution in brackets, e.g. "Mae Carol Jemison (NASA)"
• Keep your microphone muted to minimise background noise
• Make use of the chat & participants menu
• Speakers will miss the visual feedback from online participants; you can make up for that, by leaving nice remarks, using thumbs-up emojis, raising your hand, and clapping after the talks
• To ask questions, either use the "raise hand" button in the participants menu and prepare to be called up, or write them down in the chat for the chair to read them out
• Continue conversations with speakers via direct messages