MITM8 | Future and current instruments to detect and characterise extrasolar planets and their environment

MITM8

Future and current instruments to detect and characterise extrasolar planets and their environment
Co-organized by EXOA
Convener: Camilla Danielski | Co-conveners: Andrea Bocchieri, Elodie Choquet, Lorenzo V. Mugnai
Orals
| Thu, 12 Sep, 14:30–16:00 (CEST)|Room Saturn (Hörsaal B)
Posters
| Attendance Thu, 12 Sep, 10:30–12:00 (CEST) | Display Thu, 12 Sep, 08:30–19:30
Orals |
Thu, 14:30
Thu, 10:30
Exoplanets are being discovered in large numbers thanks to recent and ongoing surveys using state-of-the-art instrumentation from the ground and from space. In the next years, new astronomical instruments will scout ever more distant regions of our Galaxy and they will validate new technology for the ultimate direct characterisation of temperate exoplanets. Such a change of physical and technological horizon will allow us to overcome the current observational biases in the search of alien worlds, and to gain a deeper understanding of the chemical and physical properties of exoplanets and the environment that surround them. Ultimately we will be able to unveil processes of formation and evolution of planets, together with those of their atmospheres, on a scale much larger than our Solar Neighbourhood.

The goal of this session is to bring together the instrumentation and observational communities that are underpinning the future of this field. Contributions are invited to review ongoing programmes of exoplanet and circumstellar discs discovery and characterisation, to update on the progress of planned instrumentation programmes, and to present innovative ideas for future instrumentation.

Orals: Thu, 12 Sep | Room Saturn (Hörsaal B)

Space-Based
14:30–14:40
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EPSC2024-197
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On-site presentation
Heike Rauer, Ana Heras, Miguel Mas-Hesse, and Isabella Pagano

PLATO is ESA’s M3 mission and designed to detect and characterize extrasolar planets by photometrically monitoring a large number of stars. PLATO will detect small planets around bright stars, including terrestrial planets in the habitable zone of solar-like stars. In parallel, PLATO will study (host) stars using asteroseismology, allowing us to determine the stellar properties with high accuracy, substantially enhancing our knowledge of stellar structure and evolution. With the complement of radial velocity observations from ground, planets will be characterized for their radius, mass, and age with high accuracy. PLATO will provide us with a large-scale catalogue of well-characterized small planets up to intermediate orbital periods, relevant for a meaningful comparison to planet formation theories and to better understand planet evolution. In addition, PLATO´s Guest Observer program will allow for a number of complementary science cases, based on proposals from the community.

PLATO is scheduled for a launch date end 2026. The payload instrument consists of 26 cameras with 12cm aperture each. For at least four years, the mission will perform high-precision photometric measurements of a large number of stars (around 150.000 per field). This talk will present an overview of the PLATO instrument, the mission profile and its science goals.

How to cite: Rauer, H., Heras, A., Mas-Hesse, M., and Pagano, I.: PLATO Mission Overview, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-197, https://doi.org/10.5194/epsc2024-197, 2024.

14:40–14:50
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EPSC2024-537
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On-site presentation
Enzo Pascale, Andrea Bocchieri, Paul Eccleston, Lorenzo Mugnai, Giorgio Savini, and Giovanna Tinetti

The Ariel space mission will characterise spectroscopically the atmospheres of a large and diverse sample of hundreds of exoplanets. Targets will be chosen to cover a wide range of masses, densities, equilibrium temperatures and host stellar types to study the physical mechanisms behind the observed diversity in the population of known exoplanets. With a 1-m class telescope, Ariel will detect the atmospheric signatures from the small, <100ppm, modulation induced by exoplanets on the bright host-star signals, using transit, eclipse and phase curve spectroscopy. Three photometric and three spectroscopic channels, with Nyquist sampled focal planes, simultaneously cover the 0.5-7.8 micron region of the electromagnetic spectrum, to maximise observing efficiency and to reduce systematics of astrophysical and instrumental origin. This contribution reviews the predicted Ariel performance as well as the design solutions implemented that will allow Ariel to reach the required sensitivity and control of systematics.

How to cite: Pascale, E., Bocchieri, A., Eccleston, P., Mugnai, L., Savini, G., and Tinetti, G.: The Atmospheric Remote-sensing Infrared Exoplanet Large-survey sensitivity and performance, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-537, https://doi.org/10.5194/epsc2024-537, 2024.

14:50–15:00
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EPSC2024-1105
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On-site presentation
Yoga Barrathwaj Raman Mohan, Benjamin Wilcock, Ian Stotesbury, Marcell Tessenyi, Richard Archer, Sushuang Ma, Lawrence Bradley, Billy Edwards, Giovanna Tinetti, Jonathan Tennyson, Giorgio Savini, Philip Windred, and Ahmed Al-Refaie

The Twinkle telescope is a space-based observatory conceived to study solar system objects, exoplanets, brown dwarfs, protoplanetary disks and stars. The satellite is based on a high-heritage platform and will carry a visible and infrared spectrograph providing simultaneous broad wavelength coverage. Launching into a Sun-synchronous low-Earth polar orbit, Twinkle will operate from a highly stable thermal environment for a baseline lifetime of seven years.

In this presentation, the Twinkle team will provide the latest updates on the mission and will highlight the work undertaken by the Founding Members of the extrasolar survey, showcasing the many initial science themes under development. Focusing on the objectives, scientific justification, and high-level observation plan we will explore how Twinkle will contribute to a broad range of astrophysics research.

Additionally, we explore the observational programme being developed to provide both initial characterisation and simultaneous ground and space-based observations, demonstrating how Twinkle’s broad spectral coverage can be complementary across multiple ground and space-based telescopes.

How to cite: Raman Mohan, Y. B., Wilcock, B., Stotesbury, I., Tessenyi, M., Archer, R., Ma, S., Bradley, L., Edwards, B., Tinetti, G., Tennyson, J., Savini, G., Windred, P., and Al-Refaie, A.: Twinkle: a satellite spectroscopy mission for the next phase of exoplanet science, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1105, https://doi.org/10.5194/epsc2024-1105, 2024.

15:00–15:10
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EPSC2024-222
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ECP
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On-site presentation
Marius Anger, Aksel Søren Beltoft, Johanna Noria Brecher, Antoine Corne, Jo Ann Egger, Simone Filomeno, Margarida Graça, Viktoria Keusch, Guillem Khairy, Jakub Kowalczyk, Riccardo Lasagni Manghi, Dominik F. Loidolt, Maja Marminge, Alex McDougall-Page, Lukas Tamulevicius, Elena Tonucci, and Elise Wright Knutsen

Many exoplanets discovered so far exhibit distinct characteristics not observed within our own Solar System. With respect to planetary mass, orbital period, and radius, three categories are particularly interesting:

Hot Jupiters are gas giant exoplanets with an orbital period of less than 10 days and located closer than 0.1 AU from their host star. Especially magnetic fields have been expected in these bodies, but have not yet been detected unambiguously [Cauley et al. 2019, Trammell et al. 2011].

Sub-Neptunes are planets with a smaller radius than Neptune but near 2.0 RE (Earth radii). These planets have not been found to this day. The notable absence cannot be attributed to any discernible observational bias, thereby implying the influence of underlying processes such as
migration or atmospheric escape [Szabó et al. 2019].

Super-Earths are planets with a larger radius than Earth, yet lighter than ice giants. A distinct gap is discernible in the number of planets per star, specifically within the radius range of 1.5 RE to 2.0 RE . This so-called Radius Valley and the Hot Neptune Desert are still actively debated.
Plantes in the Radius Valley may represent an unstable region where planets transition towards a stable radius. Atmospheric escape could initiate this mechanism, including phenomena like photoevaporation [Zhang et al. 2023] and core-powered mass loss [Venturini et al. 2020]. Addressing these questions is crucial for advancing our understanding of exoplanetary systems.

The here proposed exoplanet mission, Aetheras, tries to address these questions in order to understand the formation of exoplanet systems by investigating atmospheric escape mechanisms andmeasuring proxies of magnetic fields. The mission focuses on objects in the Radius Valley and the Hot Neptune desert and tries to provide empirical evidence for the origins of these phenomena. Several 100 targets have been identified for investigation by cross-referencing different criteria for distance and planet radii with the NASA planetary archive.

Aetheras consist of a spacecraft using transit spectroscopy in the near-infrared range (1070 nm to 1090 nm) and ultraviolet range (115 nm to 285 nm) in an orbit outside the geocoronal influence (e.g. L2 Halo). The spacecraft has a weight of around 1500 kg and hosts two payloads which both use the same primary mirror of 1.5 m diameter.

With a proposed throughput of 12.96 % in UV and 34.01 % in IR the optical system is capable of capturing spectra with a resolution of 3724 and 571 respectively.
This system enables transit spectroscopy for several distinct absorption lines:

  • H Ly-α 121.40 nm to 121.75 nm
  • C II 130.00 nm to 137.00 nm
  • Mg II 277.00 nm to 281.00 nm
  • He I 1082.60 nm to 1084.00 nm

Especially the Ly-α line has been proposed as an indicator of atmospheric escape [Ehrenreich et al. 2015]. The other lines serve as additional proxies to be able to strengthen the results as well as adopt to several observation conditions [Dos Santos 2021]. Magnetic bow shocks can be also seen in exoplanet
spectroscopy [Llama et al. 2011] and present one method to probe planets for magnetic fields.

Figure 1: Spacecraft structure: 1 - solar panels, 2 - spectrometer, 3 - phased array antenna, 4 - orbital thruster, 5 - COM module, 6 - radiator, 7 - aperture, 8 - reaction wheels, 9 - RCS thrusters (x20), 10 - fuel tank, 11 - star tracker, 12 - baffle

Several studies have been made to understand the payload needs. These resulted in the here presented mission design proposal. A preliminary spacecraft has been outlined as seen in Figure 1 in addition to a data processing and ground station concept. With this, the Aetheras mission aims to be a helpful addition to the already existing instruments by focusing on exoplanet science only and providing more observation time and resolution to already existing targets as well as to new candidates once the Ariel mission is launched.


References:
[Trammell et al. 2011] ”Hot Jupiter Magnetospheres”, The Astrophysical Journal, DOI: 10.1088/0004-637X/728/2/152

[Cauley et al. 2019] ”Magnetic field strengths of hot Jupiters from signals of star–planet interactions”, Nature Astronomy, DOI: 10.1038/s41550-019-0840-x

[Szabó et al. 2019] ”The sub-Jupiter/Neptune desert of exoplanets: parameter dependent boundaries and implications on planet formation”, Monthly Notices of the Royal Astronomical Society: Letters, DOI: 10.1093/mnrasl/slz036

[Zhang et al. 2023] ”Detection of Atmospheric Escape from Four Young Mini-Neptunes”, The Astronomical Journal, DOI: 10.3847/1538-3881/aca75b

[Venturini et al. 2020] ”The nature of the radius valley-Hints from formation and evolution models”, Astronomy & Astrophysics, DOI: 10.1051/0004-6361/202039141

[Ehrenreich et al. 2015] ”A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b”, Nature, DOI:10.1038/nature14501

[Dos Santos 2021] ”Atmospheric Escape In Exoplanets: A Journey From Gas Giants To Earth Twins”, DOI: 10.13097/archive-ouverte/unige:155240

[Llama et al. 2011] ”The shocking transit of WASP-12b: modelling the observed early ingress in the near-ultraviolet”, DOI: 10.1111/j.1745-3933.2011.01093.x

How to cite: Anger, M., Beltoft, A. S., Brecher, J. N., Corne, A., Egger, J. A., Filomeno, S., Graça, M., Keusch, V., Khairy, G., Kowalczyk, J., Lasagni Manghi, R., Loidolt, D. F., Marminge, M., McDougall-Page, A., Tamulevicius, L., Tonucci, E., and Wright Knutsen, E.: Aetheras - L2 spectroscopy mission for characterisation of atmospheric escape, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-222, https://doi.org/10.5194/epsc2024-222, 2024.

15:10–15:15
Ground-based
15:15–15:25
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EPSC2024-968
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ECP
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On-site presentation
Marina Centenera, Pedro Amado, Jesús Aceituno, Sergio Burgos, Javier Flores, Kalaga Madhav, Jose Luis Ortiz, Fran Pozuelos, and Martin Roth
The MARCOT-Pathfinder Telescope (MPT), situated at the Calar Alto Observatory (CAHA) in Spain, represents the integration of a state-of-the-art Multi-Mode Photonic Lantern for usage with high-resolution spectrographs, enhancing the MARCOT-Pathfinder's optical efficiency and observational capabilities. Unlike conventional systems, the MARCOT-Pathfinder employs an array of seven small Optical Tube Assemblies (OTAs), each equipped with advanced fibre positioning systems to channel stellar light into the Multi-Mode Photonic Lantern. We will present the status of the project and summary of the studies that remain to be carried out, focusing on the work carried out to connect the MPT to a a readily available low-resolution spectrograph.
 
The MPT is a demonstrator of what could represent a significant leap in astronomical instrumentation for exoplanets research. It is the first phase of the MARCOT project which aim at developing a large aperture ground-based telescope combining several modules of tens of OTAs and reducing the cost compared to a traditional design of a telescope of the same size. For this purpose, off-the-self telescopes and commercial instrumentation have been used. A feature of this telescope is that it is modular, which allows us to increase the effective aperture by adding individual modules. The project is divided into different phases, the first of which is to demonstrate the functionality of this technology with the MPT. In phase-two we want to build a telescope with a 5-m effective aperture, using individual modules. Finally, the last phase will be to use several modules of 5-m effective aperture giving a total effective aperture of 15-m. MARCOT will be installed at Calar Alto Observatory with each of its modules enclosed in its own small dome.
 
This innovative setup allows for a unique, combination of the light collected by each individual telescope, effectively emulating a larger, monolithic telescope’s light-gathering power but at a fraction of the cost and complexity. The integration significantly increases the signal-to-noise ratio, crucial for detecting exoplanets around faint stars. The driver science case will be the detection and characterization of exoplanets, to which we will dedicate most of the guaranteed time observations. Specifically, with a MARCOT telescope featuring a 5-m effective aperture, we could access over 400 exoplanets already detected by TESS and Kepler, and conduct studies of their masses and densities. Similarly, we are interested in planetary systems around ultracool dwarfs, about which little is currently known. Detecting these faint objects requires large-aperture telescopes to collect more photons and a high-resolution spectrograph to achieve precise measurements of their radial velocity variations.

How to cite: Centenera, M., Amado, P., Aceituno, J., Burgos, S., Flores, J., Madhav, K., Ortiz, J. L., Pozuelos, F., and Roth, M.: Advancing Exoplanet Research with MARCOT: Innovative Photonic Lantern Integration for Enhanced Spectroscopic Capabilities, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-968, https://doi.org/10.5194/epsc2024-968, 2024.

15:25–15:35
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EPSC2024-1356
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On-site presentation
Sylvestre Lacour and Jean-Baptiste Le Bouquin

Dual-field interferometry, enabled by the GRAVITY instrument at the Very Large Telescope Interferometer, achieves very high contrast at very small separations. It has directly detected exoplanets, such as Beta Pictoris b, which are beyond the reach of other instruments. This presentation will provide a brief history of the technique, discuss recent advancements leveraging Gaia astrometry, and explore future prospects in light of upcoming Gaia data releases, the Extremely Large Telescope (ELT), and future space missions.

How to cite: Lacour, S. and Le Bouquin, J.-B.: Ground-based Optical Interferometry to Characterize Exoplanets, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1356, https://doi.org/10.5194/epsc2024-1356, 2024.

15:35–15:45
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EPSC2024-1186
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On-site presentation
Anthony Boccaletti

SAXO+ is a project to upgrade the SPHERE extreme Adaptive Optics instrument at the VLT to boost the current performances of detection and characterization of exoplanets and disks. 

The main science drivers are 1/ to access the bulk of the young giant planet population down to the snow line (3-10 au), to bridge the gap with complementary techniques (radial velocity, astrometry); and 2/ to observe fainter and redder targets in the youngest (1 − 10 Myr) associations compared to those observed with SPHERE to directly study the formation of giant planets in their birth environment.

SAXO+ is a second stage AO system equipped with an IR pyramid wavefront sensor for increasing the sampling frequency (from ~1 to 3 kHz) as well as the sensitivity in the infrared (+2-3 mag). SAXO+ is developed in coordination with the ESO technology development group and will serve as a demonstrator for the future planet finder (PCS) of the ELT. SAXO+ has concluded its consolidation phase in Apr 2024 and will continue its development to aim for on-sky testing in 2027. 

After introducing the science cases, we will discuss the SAXO+ project in particular the system choices and the estimation of performances based on the most recent simulations (see Figure).

 

Figure : Raw contrast estimated for SPHERE (square sympols) and SAXO+ (asterisque symbols) for several target properties (B for bright targets, R for red targets) and assuming 0.7'' seeing and tau_0=5.5ms.

How to cite: Boccaletti, A.: Upgrading SPHERE with the second stage AO system SAXO+, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1186, https://doi.org/10.5194/epsc2024-1186, 2024.

15:45–15:55
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EPSC2024-940
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ECP
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On-site presentation
Liurong Lin, Axel Potier, Ruben Tandon, Laurent Jolissaint, Audrey Baur, Derya Öztürk Çetni, and Jonas Kühn

We present the Programmable Liquid-crystal Active Coronagraphic Imager for the DAG telescope (PLACID) instrument, a novel exoplanet direct imaging facility that was recently delivered to the Turkish 4-m DAG telescope, with first light anticipated by the end of 2024. In a nutshell, PLACID consists of a fore-optics coronagraphic intermediate stage platform, installed in-between the TROIA XAO system and the DIRAC HAWAII-2RG focal-plane array. The PLACID instrument, led by a consortium of Swiss Universities contracted by the Atatürk University Astrophysics Research and Application Center (ATASAM), was delivered to ATASAM premises in March 2024 and is scheduled for on-telescope installation in the fall of 2024. Once on-sky later this year, PLACID will be the world’s first “active coronagraph” high-contrast imaging facility, fielding a pixelated spatial light modulator (SLM) acting as a dynamically programmable focal-plane phase mask (FPM) coronagraph from H- to Ks-band. 

We also detail our Python-based numerical simulator of pixelated FPM coronagraphy, built to investigate the effect of SLM-generated FPM patterns in place of classical phase masks. The simulator explores the impacts of various design choices and parameters, such as spatial sampling (SLM pixels per λ/D), phase resolution (greylevel steps) and Lyot stop sizing etc. Overall, the tool enables detailed simulations of PLACID or similar SLM-based instruments, and can support real-time operations (optimal choice of FPM for given observing conditions) and interpretation of real data. Additionally, the tool is designed to evolve in order to integrate and simulate advanced operation modes, in particular focal-plane phase diversity for coherent differential imaging (CDI) of exoplanets. We present the current status of our code, and some early conclusions on the impacts of a few key instrument design parameters. This imminent on-sky commissioning and early science operation of PLACID  will require careful planning in terms of target selection and related observational settings. To this purpose, we present the likely science discovery space for PLACID, in terms of known exoplanets, brown dwarfs and circumstellar disks, considering foreseen adaptive optics performance, achievable coronagraphic contrast, limiting magnitudes, coronagraphic inner working angle, etc. Predicted disk and binary/multiple star systems imaging performance is also investigated, with the latter being a possible niche science case for the instrument, as PLACID can uniquely generate adaptive FPMs to null multiple stars in the field-of-view.

How to cite: Lin, L., Potier, A., Tandon, R., Jolissaint, L., Baur, A., Öztürk Çetni, D., and Kühn, J.: The Programmable Liquid-crystal Active Coronagraphic Imager for the DAG telescope (PLACID) instrument: simulations, discovery space and status update , Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-940, https://doi.org/10.5194/epsc2024-940, 2024.

15:55–16:00

Posters: Thu, 12 Sep, 10:30–12:00

Display time: Thu, 12 Sep 08:30–Thu, 12 Sep 19:30
EPSC2024-1190
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On-site presentation
Gerald Mösenlechner, Roland Ottensamer, and Franz Kerschbaum

Nothing in space is ever truly stable. For space telescopes such as Ariel, this leads to a noise source in photometric and spectroscopic measurements caused by the movement of the target star or spectra (also refereed to as jitter) across the detectors inconsistent pixels. In order to minimise this source, continuously guiding the telescope becomes a necessity. 

Ariel will perform both photometric and spectroscopic observations of transiting exoplanets across multiple phases of their orbit in order to study the chemical composition of their atmosphere. Given the long duration of these observations, an unstable pointing of the telescope would add significant noise to the time series of the measurements. Therefore, Ariel is equipped with a dedicated instrument: the Fine Guidance Sensor (FGS). While the FGS is a scientific instrument that provides both low-resolution spectra and photometry in bands specific to atmospheric molecular features, it also doubles as an input for the closed loop guiding of the telescope. For this task, the FGS uses two of its three photometric channels to measure the position of the target star at a rate of 10 Hz. This positional information is then sent to the spacecrafts Attitude and Orbit Control System (AOCS), which applies the necessary corrections using the platforms actuators. In order to obtain the necessary measurements, the FGS will be equipped with dedicated guiding algorithms as part of its Instrument Application Software (IASW), which is developed by the University of Vienna.

In this paper we present the current state of the design of these methods. The algorithms are split into Target Acquisition and Tracking, where the former is used to correctly identify the star on a large field of view. On the other hand, Tracking is used during the scientific observations of the target in order to keep the instruments line of sight as stable as possible. In addition to the design and implementation of these algorithms, we also discuss their performance and our tools for their evaluation and testing. The images we use for performance testing are generated using our own simulators. These simulators are able to properly represent the noise sources we expect in the real instrument such as detector noise, line of sight jitter and smearing. Additionally, the simulators are designed to be as fast as possible to allow their reuse in closed loop testing, both in simulation environments and using real hardware.

How to cite: Mösenlechner, G., Ottensamer, R., and Kerschbaum, F.: Guiding and Target Acquisition for the Ariel Space Mission: Algorithms and Performance, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1190, https://doi.org/10.5194/epsc2024-1190, 2024.

EPSC2024-892
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ECP
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On-site presentation
Lorenzo V. Mugnai, Andrea Bocchieri, Andreas Papageorgiou, and Enzo Pascale

In designing and developing space instruments, fast and reliable tools are essential for validation and optimisation. Within the Ariel Space Mission framework, we have developed novel, versatile tools to estimate space instrument performance: ExoSim 2 and ArielRad.

ExoSim 2 is a time-domain simulator for exoplanet observations, capable of simulating exoplanetary transit, eclipse, and phase curve observations from both ground and space-based instruments. This simulation captures temporal effects such as correlated noise and systematics on the light curve, producing spectral images akin to actual observations. Developed for the Ariel Space Mission, ExoSim 2 assesses the impact of astronomical and instrumental systematics on astrophysical measurements and prepares the data reduction pipeline against realistic data sets. Its outputs can be utilised by various data reduction methods to determine the best pipeline strategy for removing systematics and to assess the confidence level of retrieved quantities. ExoSim 2 is a refactored version of the original ExoSim, featuring improved usability, customisability, and compatibility with Python 3.7+. It includes an installer, documented examples, and a comprehensive guide, allowing users to incorporate new functionalities through user-defined functions.

ArielRad is the Ariel radiometric model, which accurately predicts telescope performance for observing candidate targets across all mission photometric and spectroscopic channels. The software inputs a target description and a parameterisation of the payload, enabling the investigation of various design performances. ArielRad can simulate entire target lists, predicting the observing time and the resulting Signal-to-Noise Ratio (SNR) versus wavelength. By analysing 1000 candidate targets within a 20-minute timescale, it validates different observational strategies. The software architecture is based on ExoRad 2, which is publicly available and can be adapted for future space missions.

Together, ExoSim 2 and ArielRad provide comprehensive tools for the development, validation, and optimisation of space instruments, particularly within the Ariel Space Mission framework. Their versatility and robust performance make them valuable assets for current and future astronomical projects.

How to cite: Mugnai, L. V., Bocchieri, A., Papageorgiou, A., and Pascale, E.: Performance Simulation Tools for Space Telescopes Applied to the Ariel Space Mission, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-892, https://doi.org/10.5194/epsc2024-892, 2024.

EPSC2024-240
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ECP
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On-site presentation
Andrea Bocchieri, Lorenzo V. Mugnai, Enzo Pascale, and Angèle Syty

The European Space Agency’s Ariel mission, scheduled for launch in 2029, aims to conduct the first large-scale survey of atmospheric spectra of transiting exo-planets. Jitter in the spacecraft’s line of sight is a source of disturbance when measuring the spectra of exoplanet atmospheres. 

We will describe an improved algorithm for de-jittering Ariel observations simulated in the time domain using ExoSim2, the new Exoplanet Observation Simulator, adapted to Ariel. The jitter is based on representative simulations from Airbus Defence and Space, the Ariel spacecraft’s prime contractor. We investigate the accuracy and biases of the retrieved atmospheric spectra from the jitter-detrended observations. 

Using our algorithm to de-jitter photometric and spectroscopic data, we will demonstrate the possibility of achieving the photon noise limited performance compliant with the mission requirements across the whole Ariel spectrum. This work contributes to the development of the data reduction pipeline for Ariel, aligning with its scientific goals, while potentially benefiting other astronomical telescopes and instrumentation.

How to cite: Bocchieri, A., Mugnai, L. V., Pascale, E., and Syty, A.: Ariel detrending: algorithms to mitigate the jitter disturbance, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-240, https://doi.org/10.5194/epsc2024-240, 2024.

EPSC2024-1199
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On-site presentation
Vinooja Thurairethinam, Andrea Bocchieri, Giorgio Savini, Lorenzo V. Mugnai, and Enzo Pascale

The Ariel space mission requires the simultaneous observation of exoplanet systems in visible and infrared wavelengths through spectroscopic and photometric channels. These wavebands are selected and isolated using dichroic beamsplitters. Dichroic beamsplitters, or dichroics, are filters that rely on the optical interference occurring within thin film layers to ensure the transmission and reflection of selective wavelengths from an incident light beam. They aim to facilitate a predetermined pathway of different wavebands by manipulating the separation of precise ranges of wavelengths and play a role in determining the spectral response of an instrument.

The assumption that the layers of coating that comprise the dichroic are entirely uniform may pose a significant limitation to its physical accuracy. Complex dichroic coatings can exhibit phase effects in both transmission and reflection of light, affecting the WaveFront Error (WFE) and, consequently, the point spread function (PSF) as a function of the wavelength. The deviations in the phase observed across the surface of the dichroic are primarily the result of variations in the thickness of a given coating layer, influenced by the accuracy of the technique and equipment used during the deposition process of the coatings.

Here, we use transmission-line modelling to explore the effect of low-spatial frequency variations in the thicknesses of the layers to assess the subsequent impact on the resulting phase of the outgoing beams of a dichroic. We apply our methodology to a case study of an example dichroic that has been designed to comply with the spectral requirements of Ariel’s extreme broadband dichroic, D1.

We will show that these non-uniformities introduce a wavelength-dependent shift in the observed phases of the outgoing beam, which may subsequently degrade the PSF. We obtain estimates of the expected phase variations when subjected to low-spatial frequency errors in thickness. The physical distribution of these errors in the form of WFE maps are propagated through the optical chain of Ariel using PAOS, an open-source, generic Physical Optics Propagation code developed by Ariel scientists, to assess the consequent impact on the PSF at the focal plane of the FGS-2 photometer.

How to cite: Thurairethinam, V., Bocchieri, A., Savini, G., Mugnai, L. V., and Pascale, E.: Modelling phase errors induced by multilayer optical coating using Monte Carlo transmission line modelling and PAOS for performance sensitivity of the Ariel mission, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1199, https://doi.org/10.5194/epsc2024-1199, 2024.

EPSC2024-272
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ECP
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On-site presentation
Andrea Bocchieri, Luke Booth, and Lorenzo V. Mugnai

Twinkle and Ariel, set to launch in 2025 and 2029 respectively, will conduct the first large-scale homogeneous spectroscopic surveys of hundreds of exoplanet atmospheres. This will fully transition the field to an era of population-level atmospheric characterization. In this pilot study, we explore synergies between the two missions by focusing on a select subset of 'cool' planets well-suited for observation by both telescopes.

Using representative noise levels, we compute the number of visits needed, simulate and retrieve observed transmission spectra assuming gaseous, H2/He-dominated atmospheres. We will show that for all targets, atmospheric parameters are generally retrieved within 1-sigma of input values, with Ariel achieving tighter constraints. 

We will demonstrate exploitable synergies between Twinkle and Ariel for this 'cool' planet sample, with Twinkle potentially providing a vantage point to plan Ariel observations. As the missions' target lists take shape, we encourage further investigation by both consortium communities to fully map the synergy potential as the launch dates approach.

How to cite: Bocchieri, A., Booth, L., and Mugnai, L. V.: Exploring Synergies between Twinkle and Ariel: a Pilot Study, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-272, https://doi.org/10.5194/epsc2024-272, 2024.

EPSC2024-1206
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On-site presentation
Qinglin Ouyang, Jilin Liu, and Zhuoxi Huo
The search for habitable exoplanets and the characterization of potential biosignatures via atmospheric spectrum represent the forefront of exoplanetary research. Given the faint signals from distant exoplanets, identifying such exoplanets requires next generation observatories with high sensitivity and high resolution. Recently proposed space telescope concepts, such as Habitable-Worlds-Observatory (HWO) and Large Interferometer For Exoplanets (LIFE) aim to meet these requirements, promising to enhance the discovery and characterization of habitable exoplanets.
 
We present the Multi-spacecraft Exoplanet Aperture sYnthetic INterferometer (MEAYIN) program from China. MEAYIN utilizes nulling interferometry for direct imaging of potential habitable planets orbiting nearby solar-type stars, aiming to capture their thermal emission spectrum in the mid-infrared (MIR) band to identify biosignatures. In alignment with mission concept and scientific objectives, we report on the development of the observational simulation grid for MEAYIN. This grid, based on exoplanetary atmosphere model, simulates observational spectrum of targets under various conditions (e.g., signal-to-noise ratio, spectral resolution, and wavelength range). Furthermore, by using atmospheric retrieval analysis, we could infer the atmospheric characteristics from simulated spectrum and evaluated whether observational conditions meet observational requirements, thereby informing the instrument design for MEAYIN.
 
We aim to enhance the observational simulation grid to cover different terrestrial planets, different planetary evolutionary stages, and the effects of biological activities on atmospheres. By integrating these simulations with observational data and laboratory experiments on biosignature production mechanisms, we will deepen our understanding of potentially habitable exoplanet properties. This integrative approach will also guide the mission design and instrumentation requirements for MEAYIN and other next generation observatories.

How to cite: Ouyang, Q., Liu, J., and Huo, Z.: MEAYIN and its Observational Simulation Grid: Advancing the Search for Habitable Exoplanets and Biosignature Characterization, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1206, https://doi.org/10.5194/epsc2024-1206, 2024.

EPSC2024-620
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ECP
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On-site presentation
Citlali Bruce Rosete, Mireia Leon Dasi, Marius Anger, Paula Benitez Sesmilo, Mark R. Boyd, Frederik Dall'Omo, Simone Filomeno, Jan-Vincent Harre, Kim Angelique Kahle, Isabel Pitz, and Vito Saggese

EXODUS is a proposed mission to study the largely unexplored range of sub-Neptune to Jupiter-sized exoplanets with orbital periods longer than 100 days. The focus of the mission lies in the detection of these planets and characterisation of atmospheric escape to constrain their evolutionary pathways. Further, the activity of the host star is monitored in the ultra-violet (UV) wavelengths to distinguish between two mechanisms of atmospheric escape: UV-driven mass loss and core-powered mass loss. The proposed mission design consists of a space telescope which requires a Lissajous orbit around L2. The primary instrument consists of an Integral Field Unit (IFU) optimised for direct imaging of exoplanetary systems in the near-infrared (NIR) domain. Simultaneous monitoring of the parent star is conducted via photometric observations of the H_alpha emission. The correlation between atmospheric escape and stellar activity is studied to determine the responsible mechanism.

Science objectives

Understanding the variety of system architectures and formation histories of planetary systems remains a major challenge. Current detection methods are strongly biased towards short-period bodies, leaving a gap in the exoplanet population demographics. A mission capable of detecting and characterising exoplanets with orbital periods longer than 100 days would address these biases and add to the population demographic. Measurements of exoplanet properties have established the existence of a bimodal distribution of planetary radii, creating the so-called radius valley. This radius valley is thought to stem from planetary size evolution produced by atmospheric escape, a mass-loss phenomenon that can be core-driven or UV-driven. This process can be detected via observations of the He triplet at 1083 nm in reflected light. The EXODUS mission aims to answer the following science questions:

  • How does atmospheric escape shape the evolution of long orbital period exoplanets?
  • What proportion of the exoplanet population do exoplanets with long orbital periods represent?
  • How does the Solar System architecture compare to that of exoplanetary systems?

Payload

To answer these questions, EXODUS aims at observing a core sample of 2000 exoplanets. The payload includes two telescopes, one for NIR observations of the planet and the other for UV monitoring of stellar activity. The NIR observations are conducted with a 2.4 m diameter telescope in a Cassegrain configuration. The main target observations are performed with the MARY instrument, consisting of a high contrast coronograph and an integral field unit (IFU) equipped with a NIR detector. The configuration allows to obtain a contrast of 1E-9. The IFU is used to obtain spatially resolved full-frame spectra of the exoplanets in the 1000-2000 nm range with a 1nm spectral resolution. A secondary instrument (VISVIS) composed of three detectors is used for the fine guidance system and for monitoring of the host star with an H_alpha filter. The UV monitoring of the star is performed with a smaller secondary Cassegrain telescope, featuring a 9.3 cm primary mirror. A UV photometer measures the flux of the parent star to correlate stellar activity with atmospheric escape.

Spacecraft design

The spacecraft design is driven by the strict thermal requirement imposed by the instrument temperature constraints and the pointing requirements to achieve the desired observation contrast. The spacecraft design assesses these requirements.

To fulfill the thermal requirements, a segmented design with hot and cold sections is chosen. The spacecraft comprises four main modules: (1) the payload module with the primary mirror on top, separated by a thermally isolating structure from (2) the service module, (3) the secondary mirror’s support fixed to the payload module, and (4) the sunshield support, which protects the instruments from solar radiation.

The communication subsystem consists of a combination of a High Gain antenna system devised for science downlink and a Low Gain antenna system for telemetry and telecommand, though both are available for either operation in case of emergency, at the expense of a longer downlink time for the Low Gain system. The power subsystem design is based on three main components: solar panels for power generation, batteries for power storage, and a Power Control and Distribution Unit (PCDU) for power management throughout the spacecraft. The propulsion subsystem consists of bipropellant thrusters which use the same fuel as the Attitude Determination and Control System (ADCS). A design for the tank and fluid supply system is proposed such that either hydrazine or LMP, a green propellant that is currently being researched, can be used.

The ADCS subsystem design is driven by the required pointing accuracy of the coronagraph and the reaction wheel desaturation needed in between science measurements. For the fine pointing of the instrument, a system consisting of a Fine Steering Mirror, a Fine Guidance Sensor (FGS), which is the VISVIS instrument, and a FGS Control Unit is used. For the rough pointing and stabilisation of the spacecraft, eight mono-propellant thrusters and four reaction wheels are connected via a control unit to a system with six sun sensors, a gyroscope and two star-trackers.

The thermal control subsystem design is driven by the required temperature of the payload to avoid thermal noise in the detector. The primary objective of the sunshield is to maintain the payload operating environment at the required temperature, while avoiding an active cooling system for the payload. This reduces the complexity and enhances the reliability of the thermal system. To this end, a seven-layered sunshield was designed to reduce the temperature to the level required by the instrument at the innermost layer. To manage overall heat rejection on the spacecraft, surface coatings such as black paint and aluminized kapton are applied. Meanwhile, targeted heating and dissipation is provided with heaters, radiators, insulators and thermal couplings throughout the spacecraft.

How to cite: Bruce Rosete, C., Leon Dasi, M., Anger, M., Benitez Sesmilo, P., Boyd, M. R., Dall'Omo, F., Filomeno, S., Harre, J.-V., Kahle, K. A., Pitz, I., and Saggese, V.: EXODUS: A mission to explore exoplanet evolution through understanding atmospheric escape, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-620, https://doi.org/10.5194/epsc2024-620, 2024.

EPSC2024-282
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ECP
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On-site presentation
Fatemeh Zahra Majidi, Lawrence Bradley, Sushuang Ma, Arianna Saba, Giovanna Tinetti, Ian Stotesbury, Billy Edwards, Giorgio Savini, Fabio Favata, and Marcell Tessenyi

Mauve is a satellite equipped with a 13-cm telescope and a UV-Visible spectrometer (with an

operative wavelength range of 200-700 nm) conceived to measure stellar magnetic activity and

variability. The science program will be delivered via a multi-year collaborative survey program,

with thousands of hours each year available for long baseline observations of hundreds of stars,

unlocking a significant time domain astronomy opportunity. Mauve’s mission lifetime is 3 years

with the ambition of 5 years, and will cover a broad field of regard (–46.4 to 31.8 degrees in ICRS)

during this period.

 

This facility was conceived to support pilot studies and new ideas in science and is fully dedicated

to time-domain astronomy. The main surveys to be executed by Mauve are monitoring of

- Flare stars (flares, depending on their energy and frequency, may change the chemistry of planetary atmospheres, power prebiotic chemistry, produce surface biosignatures, or deprive exoplanets of their atmospheres totally)

- Herbig Ae/Be stars (which host protoplanetary disks and few of them are young exoplanet hosts/candidate exoplanet hosts)

- Confirmed exoplanet hosts,

- Contact binary variables (RS CVn variables, symbiotic stars, Algol-type stars, etc.), with several of them hosting exoplanets, such as AF Lep, the recently discovered benchmark system to be studied for exoplanet atmosphere characterisation for its unique features.

Besides these major science themes, the spectrometer’s data can be utilized to support and complement existing and upcoming facilities as a pathfinder, or conduct simultaneous/follow-up observations.

How to cite: Majidi, F. Z., Bradley, L., Ma, S., Saba, A., Tinetti, G., Stotesbury, I., Edwards, B., Savini, G., Favata, F., and Tessenyi, M.: Mauve: a UV-Vis satellite dedicated to monitor stellar activity and variability, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-282, https://doi.org/10.5194/epsc2024-282, 2024.

EPSC2024-1202
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ECP
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On-site presentation
Alexandra Thompson, Arianna Saba, Kai Hou Yip, Sushuang Ma, Angelos Tsiaras, Ahmed Al-Refaie, and Giovanna Tinetti

All exoplanet host stars are unique and have the capacity to exhibit stellar activity in the form of spots and faculae to differing extents and in a highly temporally variable way. It is therefore reasonable to expect that we are seeing, and will continue to see widespread stellar contamination of differing degrees throughout both current and future observations of exoplanets in transmission. Furthermore, as this contamination is potentially varying on an epoch-to-epoch basis, using a one-size-fits-all analytical approach is unwise and implausible even for a single exoplanetary system. 

For transmission spectra obtained with both current and future instruments, the majority of the information pertaining to the extent of stellar contamination is contained within the shortest wavelength datapoints in the optical regime. As such, good coverage in both the optical and the infrared is essential for conducting accurate combined star-planet retrieval analyses. Unfortunately from the stellar-perspective, the optical regime is usually less prioritised by instrumentation with respect to the infrared, where the bulk of the planetary information lies. As such the optical region tends to have a lower resolution and the datapoints themselves frequently have larger error bars leading a retrieval to assign a lower priority to them during the fitting process. Conducting retrievals on the optical data alone is also not suggested as they require the planetary information contained within the infrared to act as an anchor point in order to perform optimally. Stellar contamination is capable of introducing significant biases in the retrieved planetary parameters if not corrected for so it is paramount that we fully understand the extent of stellar contamination within our observations. In order to achieve this, we need to leverage the information content of the shortest wavelengths to the fullest extent alongside that of the infrared, both so that we can perform complete star-planet analyses of current observations with JWST and in preparation for future exoplanet-dedicated missions e.g. Twinkle and Ariel that will open up the possibility for population studies on an unprecedented scale. 

With this rationale in mind, we introduce two new, complementary metrics, the Stellar Activity Distance (SAD) metric and the Stellar Activity Temporal (SAT) metric which are designed to indicate the extent of stellar contamination at the time of observation in a highly interpretable way. These metrics are intended to aid in the assessment of different retrieval models, alongside existing model comparison tools e.g. the Bayes Factor and activity indicators e.g. log(R′ HK), the uses of which are already well-cemented within the literature, to give a bigger picture context of the host stars stellar activity level, both during an individual observation and over subsequent visits. 

Briefly, the SAD is a chi-squared inspired, goodness-of-fit metric that focuses solely on wavelengths bluewards of 1µm. At first order the SAD seeks to determine whether any slopes in the optical data can be sufficiently reproduced by a Rayleigh scattering slope from atmospheric hazes alone, or whether or not an additional departure from Rayleigh scattering due to stellar contamination is required. This departure can be either in the form of strengthening the positive bluewards slope as is expected for a spot-dominated activity regime or nullifying/reversing the slope in the case of a faculae-dominated regime. The SAD complements the Bayes Factor as although both tools are founded on a similar ideology, they differ in that the SAD focuses solely on the fit in the optical regime, whereas the Bayes Factor indicates which model is preferred by the entire observed spectrum. In contrast, the SAT is designed to assess the repeatability, or lack thereof, of observations from subsequent visits to the same exoplanetary system. As such the SAT requires that the system has been observed at at least two different epochs with the same instrument. By taking the pairwise differences between each datapoint and computing the average we can quantify the differences between multiple observations both in ppm, or as a percentage difference with respect to the planets weighted average transit depth in the IR allowing for comparability between systems. The use of both of these metrics for WASP-6b, a planet orbiting a well-known active host star, are shown in Fig. 1 below.

Figure 1. Left – The Stellar Activity Distance metric (SAD) calculation for a single dataset combining visits with HST STIS grisms G430L and G750L for WASP-6b. The best fit retrieved spectra for two retrieval instances are plotted with the retrieval model accounting for stellar contamination shown in orange and the retrieval model neglecting this shown in cyan. The SAD is calculated as the average distance of the baseline model from the observation divided by the average distance of the stellar contamination model and here shows a strong preference for the inclusion of stellar activity for these observations of WASP-6b. Right – The Stellar Activity Temporal metric (SAT) calculated for the same planet for two G430L visits taken at different epochs. The two observations, shown in purple and cyan, appear to increasingly diverge as a function of decreasing wavelength. The orange dashed line represents the weighted average transit depth for WASP-6b calculated from the HST WFC3 observation in the IR. Adapted from Saba et al. (2024)

 

In this presentation I will introduce these metrics and show their application to both current observations with HST STIS (Saba et al. 2024) and future observations with Ariel, where they will enable us to extract as much information about the host star and its activity level from the optical FGS photometers as possible. I hope to demonstrate that, alongside other traditional activity indicators, these metrics may be used to give us a better understanding of which exoplanetary systems require follow-up observations through large, ground-based, stellar-focused surveys in order to adequately characterise the host star before we can accurately include their planets within our studies of comparative exoplanetology

REFERENCES
Saba, A., Thompson, A., Hou Yip, K., et al. 2024, arXiv:2404.15505. doi:10.48550/arXiv.2404.15505

How to cite: Thompson, A., Saba, A., Yip, K. H., Ma, S., Tsiaras, A., Al-Refaie, A., and Tinetti, G.: Designing new Stellar Activity Metrics for use with Exoplanet Transmission Spectra Obtained with both Current and Future Missions, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1202, https://doi.org/10.5194/epsc2024-1202, 2024.

EPSC2024-1127
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ECP
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On-site presentation
Gemma Domènech Rams, Kike Herrero, Pere Gil, David Baroch, and Francesc Domene

The diversity of upcoming exoplanetary missions, both space and ground-based, will provide unprecedented view of the extrasolar planet population in the broader Galactic context. Missions like PLATO and ARIEL will build on the work of Kepler and TESS by discovering more planets with bright host stars and characterising the atmospheric compostition of a miriad of planetary systems. This is already presenting a need for systematic and coordinated ground-based follow-up observations to better support these missions. The rapid reaction and flexible, remote scheduling capabilities of robotic facilites makes them powerful tools for scientific explotation of time domain topics in general, and in particular of exoplanets and characterisation of their host stars.

We introduce the Joan Oró telescope (TJO), a fully-robotic 0.8m telescope at the Montsec Observatory dedicated to astrophysical research and Space Surveillance and Tracking activities. We present past and ongoing involment in exoplanetary research, such as photometric follow-up programs of CARMENES, TESS and ARIEL targets, and the potential for transient alert observations and unattended long-term monitoring in support of the next generation of exoplanetary surveys.

How to cite: Domènech Rams, G., Herrero, K., Gil, P., Baroch, D., and Domene, F.: Robotic follow-up in the era of exoplanetary surveys:the TJO telescope at Montsec Observatory, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1127, https://doi.org/10.5194/epsc2024-1127, 2024.

EPSC2024-386
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ECP
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On-site presentation
Heleri Ramler and Tõnis Eenmäe

Tartu Observatory's telescopes offer unique guaranteed access to objects in the Northern Hemisphere, facilitating long-term monitoring of various targets. Our largest 1.5 m instrument, has recently undergone significant upgrades, including the installation of a medium-resolution fibre-fed echelle spectrograph covering a bandwidth from 390 nm to 750 nm. This spectrograph offers flexibility with input options between two different fibre sizes, enabling retrieval of medium-resolution spectra.

Moreover, a custom-designed 4-channel instrument cube has been integrated, allowing for the attachment of two additional instruments to the telescope. Among these additions is a photometer equipped with Johnson-Cousins BVRI and Sloan g’r’i’z’ filters. These upgrades enhance our spectroscopic and photometric capabilities, particularly for studying celestial objects such as transits, exoplanet host stars, asteroids, and transients.

In our presentation, we will provide an update on the status of these projects, detailing the improvements made and the impact on our observational capabilities.

How to cite: Ramler, H. and Eenmäe, T.: New fibre-fed Echelle spectrograph and photometer on 1.5 m telescope at Tartu Observatory, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-386, https://doi.org/10.5194/epsc2024-386, 2024.

EPSC2024-67
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On-site presentation
Nicolas Lodieu, Jeff Kuhn, Rafael Rebolo, Patricia Fernandez, Paula Sola La Serna, Maria Auxiliadora Padron, Natalia Arteaga Marrero, Alejandro Ruiz Sabina, Diego Alberto Tamayo, Gil Moretto, and Maud Langlois

Ground-breaking science like the search for life in the atmospheres of exoplanets requires telescopes with extemely large diameters (>35m). Emerging
technology can build competing and complementary to the large astronomical telescopes being built and designed to achieve some specific science cases such as the detection and study of life-bearing exoplanets in the nearest 100 star systems. In particular, Fizeau optics, non-subtractive shaping of thin mirrors, photonics and neural-network wavefront sensing, active/adaptive optics, integral robotics and tensegrity structures, are key.

Our team is currently working on the design and construction of a 3.5m precursor telescope, using some of these disruptive technologies. The so-called Small ExoLife Finder (Small-ELF) costs about 5Me and can be finished within the next 5 years to detect nearby large exoplanets. This research and development was recently funded
by the European Union to create a new sustainable "Laboratory for Innovation in Optomechanics"  at the IAC (Tenerife) led by Prof Jeff Kuhn. LIOM plans for a 50m ExoLife Finder to be built within 10 years for about 200Meur - more than an order of magnitude less than the Keck-era and ELT telescopes. LIOM aims at (1) developing ultra-thin light mirrors with novel engineered materials to reduce the cost and weight of future telescopes. Moreover, our team is developing (2) designing lighter structures with pre-tensioned cables to support mirrors and lighten structures, and (3) integrating photonic devices that allow more thermal and mechanical stability cost savings with high replicability.

The talk will review our progress on all these fronts.

How to cite: Lodieu, N., Kuhn, J., Rebolo, R., Fernandez, P., Sola La Serna, P., Padron, M. A., Arteaga Marrero, N., Ruiz Sabina, A., Tamayo, D. A., Moretto, G., and Langlois, M.: Small-ELF (SELF): a powerful telescope for high-contrast astronomy and a prototype for the future >30-meter ExoLife Finder (ELF) hybrid optical telescope, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-67, https://doi.org/10.5194/epsc2024-67, 2024.

EPSC2024-1157
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On-site presentation
Claude Aime, Céline Theys, and Simon Prunet

We can hope that, in a near future, external occulter systems, called Starshade will allow the detection of exo-Earth type exoplanets, but as unresolved points.  The telescopes used will be of a few meters.To get real multi-pixels images of  exoplanets,  interferometry with diluted apertures separated from each other by several hundred meters will be necessary. Can we combine interferometry and external occulters? This is the problem that we examine in our work.

How to cite: Aime, C., Theys, C., and Prunet, S.: Starshades and interferometry for exoplanet imaging, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1157, https://doi.org/10.5194/epsc2024-1157, 2024.