arXiv subjects

Sascha P. Quanz

Publications and source records attributed to Sascha P. Quanz.

At least 19 recordsLinked to original sources

arXiv2026

On the Impact of Correlated Noise and Spectral Resolution on the Retrieval Analysis of the Habitable World Observatory

Finding signs of life elsewhere in the universe is the holy grail of the field of exoplanets. Future space missions such as the Habitable World Observatory (HWO) are under development to search for biosignatures in exoplanets. We investigate the impact of correlated noise and spectral resolution on the retrieved biosignature chemical abundances. At the nominal spectral resolving power R=140 for HWO, we show that in 40\% of the simulated runs the retrieved biosignature (H$_2$O and O$_2$) abundances are at least 1-$σ$ off the input ground truth. At R=1000, the 1-$σ$ inaccuracy rate drops to 10\%. We provide an empirical relationship between the retrieved biosignature abundance uncertainty and the amplitude of the correlated noise. As part of the mitigation plan to reduce the impact of correlated noise on retrieval accuracy at low spectral resolution, we investigate the synergy between the HWO and LIFE space missions that cover ultraviolet, optical, and thermal-infrared wavelengths. After considering clouds and their effect on planet albedo, we find that the two missions are complementary in that (1) more biosignatures (H$_2$O, CO$_2$, O$_2$, and O$_3$) are detectable with a broader wavelength coverage; (2) retrieval uncertainty improves with the joint HWO+LIFE data set; and (3) LIFE is more sensitive to the atmospheric temperature profile, surface pressure, and planet radius. This work provides evidence to support the choice of a medium resolution at R=1000 instead of R=140 for HWO and a quantitative relationship between the retrieved abundance uncertainty and the level of correlated noise at different spectral resolutions.

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arXiv2026

Upgrading LBTI/NOMIC with a quadruple annular groove phase mask and GeoSnap detector for imaging nearby, habitable-zone exoplanets

The Large Binocular Telescope Interferometer (LBTI)'s Nulling-Optimized Mid-Infrared Camera (NOMIC) is among the most capable thermal-infrared imaging systems available for high-contrast, high-angular-resolution astronomical observations. Here we describe two in-progress upgrades to LBTI/NOMIC: (1) the design, fabrication, and installation of a quadruple annular groove phase mask (Q-AGPM) coronagraph, and (2) the installation of a 13 micron-cutoff Teledyne GeoSnap array. The Q-AGPM is the first coronagraph to be installed within NOMIC and one of the first optimized for N-band (~11 micron) observations. It places four annular groove phase masks on a single diamond substrate so that, in the LBTI dual-aperture imaging mode, each of the two telescope beams can be chopped between a pair of masks without loss of observing efficiency. The GeoSnap array will replace NOMIC's original AQUARIUS array, delivering higher quantum efficiency, larger well depth, faster and more linear readout, and freedom from the excess low-frequency noise that requires aggressive chopping. Together these upgrades substantially improve the achievable contrast and sensitivity at small angular separations. We also present a high-contrast Fizeau imaging sequence obtained with LBTI's new FFTCam fringe tracker, which confirms the interferometric gain over a single aperture through injection/recovery tests: relative to an equal-time single aperture exposure, the S/N = 3 contrast is a factor of ~2-4 deeper across 0.2-1 arcsec, spanning the contrast- and background-limited regimes. Finally, we describe the role of the upgraded LBTI/NOMIC instrument within the Breakthrough Watch program at the University of Arizona, which aims to perform the deepest observations yet of the habitable zones of the nearest single Sun-like stars.

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arXiv2026

Cryogenic characterisation for the Nulling Interferometry Cryogenic Experiment (NICE)

The Nulling Interferometry Cryogenic Experiment (NICE) is an experimental testbed for the beam combiner of the Large Interferometer For Exoplanets (LIFE) space mission. Until now, progress on NICE has been confined to an ambient bench, where we have recorded progress in deep ($<10^{-5}$) nulls at wavelengths between 4 and 5 microns at 300 K. However, the ultimate goal and requirement of NICE is to repeat these measurements at the sensitivity levels expected for a planetary system, requiring deep cryogenic conditions at 15 K. Here, we describe the ``Ice Cube'' cryostat, a small version of the future NICE cryostat that is used for component and subsystem level cryogenic testing. This is interfaced with a measurement setup using a segmented aperture interferometer and a wavefront sensor. We will also describe the testing campaign for understanding the material and mounting challenges that will be faced when translating the warm bench to cryogenic operations.

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arXiv2026

A NICE (Nulling Interferometry Cryogenic Experiment) update: Beyond 1e-5 and towards cryogenic operation

The Nulling Interferometry Cryogenic Experiment (NICE) is a mid-infrared laboratory testbed at ETH Zürich that aims to not only reproduce the deep ($<1\times10^{-5}$) broadband nulls of the nulling testbeds of the early 2000s, but also at the required sensitivity levels expected for the LIFE space mission. This sensitivity enforces the experiment to go cryogenic at temperatures around 15 K; an ambitious task for an ultra-precise interferometer. We share our results of the ambient precursor experiment, demonstrating repeatable $<1\times10^{-5}$ nulls at a single wavelength and high throughput, and investigations into the nulling performance across a broader bandpass and with dual polarisation states. We will also highlight the push towards cryogenic operation, with the instalment of a new 15 K test cryostat that will inform our choices of materials and optomechanical mounting techniques.

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arXiv2026

The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems VIII: patchy forsterite and enstatite clouds in the atmosphere of VHS 1256 b, retrieval lessons learned and outlook to the future

JWST defines a new era for the data-driven approach of retrieval modelling, which has become a cornerstone tool for the statistical inference of exoplanetary and brown dwarf properties. The Early Release Science program #1386 observations of VHS 1256 b represent a huge jump in data quality, data quantity and spectral coverage for such objects. VHS 1256 b is a young, planetary mass and extremely variable companion that populates the enigmatic L/T cohort of substellar atmospheres. In this first retrieval analysis of the full 1 - 18 micron dataset, we apply the Brewster retrieval framework to the NIRSpec and MIRI spectroscopic observations of VHS 1256 b, exploring a variety of cloud species and structures. Using Delta(BIC) we find that the data is best described by a forsterite (Mg$_{2}$SiO$_{4}$) and enstatite (MgSiO$_{3}$) cloud combination. Our analysis shows a strong preference for patchy silicate cloud coverage, which aligns with VHS 1256 b's extensive and well documented spectral variability. Our retrieval is able to place constraints on the abundances of H$_{2}$O, CO, CO$_{2}$, CH$_{4}$ as well as NH$_{3}$. We also show that the retrieved parameters are sensitive to the data used and the relative signal-to-noise ratios between data from different instruments. We conclude with the next steps for the wider retrieval community to better understand young and cloudy exoplanetary atmospheres.

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arXiv2026

Characterizing the oxidation state of rocky exoplanets with the Large Interferometer for Exoplanets (LIFE)

The oxidation state of rocky exoplanets is expected to play a fundamental role in shaping the chemical composition of their secondary atmospheres by influencing the chemical composition of volcanically released gasses. Distinguishing planetary redox states through direct atmospheric characterization would offer insight into the formation and evolution of secondary atmospheres on exoplanets and inform the background chemistry of putative biosignatures. The Large Interferometer For Exoplanets (LIFE) mission concept aims to employ a space-based mid-infrared nulling interferometer to characterize exoplanetary atmospheres. In this work, we assess LIFE's performance in distinguishing the redox states of rocky exoplanets by direct spectroscopic measurements. We focus on the observability and spectral features of redox-sensitive molecules in secondary atmospheres of Earth-sized exoplanets. We develop and apply a retrieval framework based on the ARtful modeling Code for exoplanet Science (ARCiS) and the LIFE mission simulator (LIFEsim) to simulate observations of Earth-sized planets with atmospheres from a range of plausible mantle redox conditions. Our simulations show that LIFE in its baseline configuration can successfully constrain dominant atmospheric species (e.g. CO2, CH4 and NH3) with sufficient accuracy to distinguish redox states for planets orbiting a Sun-like star at 10 pc. Retrieved redox-sensitive molecules show clear trends across oxidation states, with CO2 dominating in oxidizing (with oxygen fugacity fO2 $\sim$ IW+2 to IW+6, where IW is the iron-w$ü$stite buffer) environments and NH3 in reducing (fO2 $\sim$ IW-2 to IW-6) environments, and CH4 serving as a strong tracer among intermediate (fO2 $\sim$ IW+4 to IW-4) oxidation states.

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arXiv2026

Detecting habitable exoplanet atmospheres with LIFE, the Large Interferometer for Exoplanets

A key goal of astronomers with the next generation telescopes is to detect signs of life in exoplanet atmospheres. NASA's next flagship is the Habitable Worlds Observatory (HWO). In the context of ESA's Voyage 2050 program, the Senior Committee report prioritises detecting habitable exoplanet atmospheres in the mid-IR. The most suited mission for this is the Large Interferometer for Exoplanets (LIFE) which can detect an even wider range of biosignatures than HWO and at lower concentrations. LIFE is a global science collaboration based out of ETH Zürich. With the UK's expertise in building infrared instruments we could play a leading role in realising an ambitious European-led mission. Notably, LIFE is able to detect necessary planetary context like surface temperature and pressure, along with a key discriminator molecule for biosignature false positives, methane, which will be much harder or impossible with HWO. Also, LIFE will be able to investigate many of the nearby rocky exoplanets known from radial velocity searches that are inaccessible to HWO due to its limited spatial resolution.

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arXiv2026

Direct Imaging Discovery of Giant Exoplanet $β$ Pictoris d: A Decade-Long Game of Hide-and-Seek

We report the direct imaging discovery of a third exoplanet in the $β$ Pictoris system. We detect $β$ Pictoris d ($β$ Pic d) in non-coronagraphic observations obtained with VLT/ERIS as well as multi-epoch archival datasets from JWST/NIRCam and VLT/SPHERE. Astrometric measurements over an 11-year baseline demonstrate that it is consistent with a gravitationally-bound source with orbital motion. Joint multi-planet orbit fits of all three planets in the system yield a semi-major axis of $26.0^{+2.2}_{-6.1}$ au and inclination $89.0^{+0.7}_{-0.6}$ deg for planet d. $β$ Pic d has a larger orbital semi-major axis than the other known planets in the system, but is coplanar with the inner two planets, and its orbit is consistent with sculpting the inner edge of the debris disk. $β$ Pic d has a contrast of $ΔL^{\prime}=12.11\pm0.15$ mag, with colors and luminosity that closely match those of 51 Eri b, another exoplanet in the $β$ Pictoris moving group. Its VLT/ERIS and JWST/NIRCam colors are distinct from those of free-floating planetary-mass objects of a similar age and temperature. Its red $F410M-F444W$ color indicates strong CO$_2$ absorption in its atmosphere and suggests significant enhancement in metals compared to free-floating objects. From the ATMO hot-start evolutionary models, we estimate an effective temperature of $600^{+45}_{-60}$ K and mass of $2.4\pm0.6$ $M_{\rm Jup}$, which also closely matches similar estimates for 51 Eri b. $β$ Pic d is among the lowest-mass exoplanets imaged from the ground. This discovery highlights the deep sensitivity achievable with ground-based imaging in the mid-infrared and the discovery potential of future high-contrast observations with the Extremely Large Telescope.

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arXiv2026

Exploring Exoplanets with Interferometry

(Extract from the Executive Summary) Humanity stands at the threshold of answering one of its most profound questions: Does life exist beyond Earth? Ongoing and upcoming space missions, together with powerful ground-based instruments, have prepared the way for a transformational next step - the detailed characterization of Earth analogs orbiting Sun-like and other stars and the search for atmospheric biosignatures that may indicate life. Within this context, the European Space Agency's Voyage 2050 process has identified the direct detection of thermal emission from temperate terrestrial exoplanets in the mid-infrared (mid-IR) as a top scientific priority. The Large Interferometer For Exoplanets (LIFE) - a space-based, mid-IR nulling interferometer - is designed to meet this goal. LIFE will be capable of detecting climate-relevant gases such as CO$_2$ and H$_2$O, identifying classical biosignatures like O$_3$ and CH$_4$, and probing additional, non-classical biosignatures. It will also provide key data for determining planetary radius, albedo, and temperature, which are essential for assessing habitability. In parallel, the U.S. National Academy has recommended a complementary mission now called the Habitable Worlds Observatory (HWO) - a ~6-meter space telescope equipped with advanced coronagraphs to suppress starlight by a factor of ~10$^{10}$ across the visible and possibly into the near-infrared and near-ultraviolet. Together, LIFE and HWO offer synergistic capabilities, enabling a comprehensive and robust assessment of the prevalence of life-bearing exoplanets in our galactic neighbourhood - a first in human history. By uniting an international and interdisciplinary community of scientists and engineers, LIFE offers a credible pathway toward the direct detection and characterization of potentially habitable - and even inhabited - worlds.

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arXiv2026

A preliminary exploration of the effects of baseline length for the LIFE space mission

By aiming to find and characterise dozens of habitable exoplanets through the technique of nulling interferometry, the LIFE space mission will produce transformational science. One of the key parameters for such an interferometric mission is the nulling baseline length - the distance between nulled apertures, which past studies have assumed to be 10-100m. Advances in planet occurrence statistics and simulation tools allow us now to revisit this key assumption with significantly more detail, particularly with the intention to reduce the range of baselines considered due to mission implementation concerns. We utilise the LIFEsim mission simulator along with revised mathematical tools to identify whether the range of baselines could be reduced without significantly affecting planet yield and fringe tracking performance. Along the way, we also determine a new astrophysically motivated technique for choosing which baselines are optimal for a given science target. We find that indeed, LIFE could utilise a considerably shorter range of baselines, such as 25-80m, or even discrete baselines without much (<10%) loss of performance. Nevertheless, careful trade-offs between performance and implementation simplification must be made, especially considering any spectral weighting that may be required by the scientific goals, and the potential loss of target-specific baseline optimisation.

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arXiv2026

The Nulling Interferometry Cryogenic Experiment (NICE): Architecture, requirements, and preliminary warm precursor results

The success of the Large Interferometer For Exoplanets (LIFE) space mission depends on measuring the faint mid-infrared emission spectra of exoplanets while suppressing the glare of a host star. This requires an instrument capable of high-contrast nulling interferometry with exceptional sensitivity. While previous testbeds have proven the principle of deep, stable nulls, they have not combined high contrast with the high throughput and cryogenic operation required for LIFE. Here, we present the architecture of the Nulling Interferometry Cryogenic Experiment (NICE), a mid-infrared nulling testbed, to increase the technological readiness of LIFE. We derive the laboratory requirements necessary to validate the LIFE beam combiner and present the optical design of NICE. Finally, we report results from the ambient \enquote{Warm Bench} precursor, which has successfully demonstrated the required null depth ($< 10^{-5}$) using a polarized narrowband 4.7 um source, and the required throughput (> 17%) using one of the two nulling channels.

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arXiv2026

The Goldilocks problem for detecting water in terrestrial planets: Constraining water abundances in the mid-IR with LIFE

We investigate how well the Large Interferometer for Exoplanets (LIFE) mission concept can detect habitable conditions on exoplanets through the presence of atmospheric water vapor as a proxy for surface oceans. We model the atmosphere of a pre-biotic Earth-like planet across a range of water concentrations, from water-poor to water-rich, with surface partial pressures from 10$^{-7}$ to 1 bar of H$_2$O. We simulate LIFE-like noise at spectral resolutions R = 50 and 100 using LIFEsim and perform Bayesian atmospheric retrievals to determine the technical requirements for LIFE to confirm habitability. We model three vertical water distributions: a vertically constant profile, a Manabe-Wetherald based Earth-like profile, and a diffusion and photochemistry profile to test how the assumed vertical structure influences the retrieved abundances. Clouds are not modeled. We find the ability for LIFE to detect water strongly depends on the vertical profile assumed. LIFE is unable to constrain the highest water cases and provides upper limits on low water planets. For the highest water abundances, absorption features saturate and reduce sensitivity to characterize precise H$_2$O levels. Water vapor is not detectable in any profile modeled for $\leq10^{-6}$ bar in surface water, comparable to Mars. For an Earth-like profile, LIFE could constrain H$_2$O concentrations from $\sim10^{-3}$ to 1 bar, spanning below and above present-day Earth concentrations of 10$^{-2}$ bar. Detectable atmospheric water may imply surface oceans, as water is highly reactive and rapidly removed by surface mineral reactions. Thus, LIFE can characterize water abundances indicative of habitable surface conditions.

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arXiv2026

Climates of Terrestrial Exoplanets and Biosignatures

Understanding the climates of terrestrial exoplanets and the detectability of biosignatures is an inherently interdisciplinary challenge, requiring the integration of insights from Solar System exploration, exoplanet observations and climate science. Building from Earth as the only known inhabited planet, NCCR PlanetS has developed models, tools and observational strategies to assess planetary environments far beyond direct reach. Between 2018 and 2025, PlanetS made major contributions across theory, modelling, instrumentation and mission preparation. On the modelling side, the Generic Planetary Climate Model enabled climate studies across a wide range of planetary regimes, from early Venus to temperate terrestrial exoplanets including Proxima b, incorporating advanced developments such as a dynamical slab ocean. In parallel, the THOR global climate model was developed to avoid Earth-centric assumptions and to stably simulate diverse atmospheric regimes. PlanetS has also advanced atmospheric retrieval techniques combining forward modelling, Bayesian inference and machine learning, applied to targets ranging from Solar System bodies to exoplanet phase curves and directly imaged spectra. These efforts have helped assess the scientific return of future missions, notably the Large Interferometer for Exoplanets (LIFE) and to define instrumental requirements for detecting Earth-like atmospheres and biosignatures. Within the Solar System, PlanetS contributed key technologies for biosignature detection, including ORIGIN and SenseLife, enabling in-situ and remote detection of organics, isotopic ratios and microstructures. Finally, PlanetS has played a major role in preparing the next generation of observatories, from JWST, VLT and ELT instruments to LIFE and the Habitable Worlds Observatory. Together, these contributions form an integrated framework advancing the search for life beyond Earth.

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arXiv2025

Planetary albedo is limited by the above-cloud atmosphere: Implications for sub-Neptune climate

Energy limits that delineate the `habitable zone' for exoplanets depend on a given exoplanet's net planetary albedo (or `Bond albedo'). We here demonstrate that the planetary albedo of an observed exoplanet is limited by the above-cloud atmosphere - the region of the atmosphere that is probed in remote observation. We derive an analytic model to explore how the maximum planetary albedo depends on the above-cloud optical depth and scattering versus absorbing properties, even in the limit of a perfectly reflective grey cloud layer. We apply this framework to sub-Neptune K2-18b, for which a high planetary albedo has recently been invoked to argue for the possibility of maintaining a liquid water ocean surface, despite K2-18b receiving an energy flux from its host star that places it inside of its estimated `habitable zone' inner edge. We use a numerical multiple-scattering line-by-line radiative transfer model to retrieve the albedo of K2-18b based on the observational constraints from the above-cloud atmosphere. Our results demonstrate that K2-18b's observed transmission spectrum already restricts its possible planetary albedo to values below the threshold required to be potentially habitable, with the data favouring a median planetary albedo of 0.17-0.18. Our results thus reveal that currently characteriseable sub-Neptunes are likely to be magma-ocean or gas-dwarf worlds. The methods that we present are generally applicable to constrain the planetary albedo of any exoplanet with measurements of its observable atmosphere, enabling the quantification of potential exoplanet habitability with current observational capabilities.

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arXiv2025

Robust Data Interpretation for Perturbed Nulling Interferometers via Proper Handling of Correlated Errors

The detection and atmospheric characterization of potentially habitable, temperate terrestrial exoplanets using a space-based mid-infrared nulling interferometer is a major goal of contemporary astrophysics. A central part of the analysis of such an instrument are correlated errors arising from perturbations in the system. While previous studies have often treated their effects in a limited manner, we aim to treat them comprehensively here and argue that data whitening based on the covariance of these errors is a suitable method to mitigate their impact. We present a framework that quantitatively connects instrumental perturbations to performance metrics and develop two computational tools to support our analysis: PHRINGE, for the generation of synthetic nulling data, and LIFEsimMC, a new Monte Carlo-based end-to-end simulator for the Large Interferometer For Exoplanets (LIFE). Applying our framework to a reference observation of an Earth twin orbiting a Sun twin at 10 pc, we find that whitening is not only essential for a correct interpretation of the detection metric used in hypothesis testing, but also improves the estimates of the planetary properties. Moreover, our approach enables an estimation of the spectral covariance of the extracted planetary spectra, providing valuable additional input for future atmospheric retrievals. We therefore recommend incorporating the framework into performance assessments and requirement derivations for future nulling interferometers.

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arXiv2025

Consequences of Non-Gaussian Instrumental Noise in Perturbed Nulling Interferometers

With the astrophysics community working towards the first observations and characterizations of Earth-like exoplanets, interest in space-based nulling interferometry has been renewed. This technique promises unique scientific and technical advantages by enabling direct mid-infrared observations. However, concept studies of nulling interferometers often overlook the impact of systematic noise caused by instrument perturbations. Earlier research introduced analytical and numerical models to address instrumental noise and, building on these results, we reproduce key simulations and report that the noise in the differential output of nulling interferometers follows a non-Gaussian distribution. The presence of non-Gaussian noise challenges the validity of classical hypothesis tests in detection performance estimates, as their reliance on Gaussian assumptions leads to overconfidence in detection thresholds. For the first time, we derive the true noise distribution of the differential output of a dual Bracewell nulling interferometer, demonstrating that it follows iterative convolutions of Bessel functions. Understanding this noise distribution enables a refined formulation of hypothesis testing in nulling interferometry, leading to a semi-analytical prediction of detection performance. This computationally efficient instrument model, implemented in a publicly available codebase, is designed for integration into science yield predictions for nulling interferometry mission concepts. It will play a key role in refining key mission parameters for the Large Interferometer For Exoplanets (LIFE).

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arXiv2025

Detecting Atmospheric CO2 Trends as Population-Level Signatures for Long-Term Stable Water Oceans and Biotic Activity on Temperate Terrestrial Exoplanets

Identifying key observables is essential for enhancing our knowledge of exoplanet habitability and biospheres, as well as improving future mission capabilities. While currently challenging, future observatories such as the Large Interferometer for Exoplanets (LIFE) will enable atmospheric observations of a diverse sample of temperate terrestrial worlds. Using thermal emission spectra that represent conventional predictions of atmospheric CO2 variability across the Habitable Zone (HZ), we assess the ability of the LIFE mission - as a specific concept for a future space-based interferometer - to detect CO2 trends indicative of the carbonate-silicate (Cb-Si) weathering feedback, a well-known habitability marker and potential biological tracer. Therefore, we explore the feasibility of differentiating between CO2 trends in biotic and abiotic planet populations. We create synthetic exoplanet populations based on geochemistry-climate predictions and perform retrievals on simulated thermal emission observations. The results demonstrate the robust detection of population-level CO2 trends in both biotic and abiotic scenarios for population sizes as small as 30 Exo-Earth Candidates (EECs) and the lowest assessed spectrum quality in terms of signal-to-noise ratio, S/N = 10, and spectral resolution, R = 50. However, biased CO2 partial pressure constraints hinder accurate differentiation between biotic and abiotic trends. If these biases were corrected, accurate differentiation could be achieved for populations with $\geq$ 100 EECs. We conclude that LIFE can effectively enable population-level characterization of temperate terrestrial atmospheres and detect Cb-Si cycle driven CO2 trends as habitability indicators. Nevertheless, the identified biases underscore the importance of testing atmospheric characterization performance against the broad diversity expected for planetary populations.

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arXiv2025

What if we find nothing? Bayesian analysis of the statistical information of null results in future exoplanet habitability and biosignature surveys

Future telescopes will survey temperate, terrestrial exoplanets to estimate the frequency of habitable ($η_{\text{Hab}}$) or inhabited ($η_{\text{Life}}$) planets. This study aims to determine the minimum number of planets ($N$) required to draw statistically significant conclusions, particularly in the case of a null result (i.e., no detections). Using a Bayesian framework, we analyzed surveys of up to $N=100$ planets to infer the frequency of a binary observable feature ($η_{\text{obs}}$) after null results. Posterior best fits and upper limits were derived for various survey sizes and compared with predicted yields from missions like the Large Interferometer for Exoplanets (LIFE) and the Habitable Worlds Observatory (HWO). Our findings indicate that $N=20-50$ ``perfect'' observations (100\% confidence in detecting or excluding the feature) yield conclusions relatively independent of priors. To achieve 99.9\% upper limits of $η_{\text{obs}} \leq 0.2/0.1$, approximately $N \simeq 40/80$ observations are needed. For ``imperfect'' observations, uncertainties in interpretation and sample biases become limiting factors. We show that LIFE and HWO aim for sufficiently large survey sizes to provide statistically meaningful estimates of habitable environments and life prevalence under these assumptions. However, robust conclusions require careful sample selection and high-confidence detection or exclusion of features in each observation.

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