A Flexible Bayesian Framework for Assessing Habitability with Joint Observational and Model Constraints

Truitt, Amanda; Young, Patrick; Walker, Sara Imari; Spacek, Alexander

doi:10.3847/1538-3881/ab4e93

Cited by 18 publications

(23 citation statements)

References 80 publications

(81 reference statements)

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“…For instance, the biosignature search community is developing many mature frameworks for designing and interpreting the results of life detection experiments, including the development and selection of good biosignatures to search for, selection criteria and prioritization of target lists, and frameworks for determining the confidence of detection and dealing with ambiguity (Stark et al 2019;Truitt et al 2020;Tuchow & Wright 2020, 2021Neveu et al 2018;Green et al 2021, to give a few recent examples in addition to the references in Section 1).…”

Section: Discussionmentioning

confidence: 99%

The Case for Technosignatures: Why They May Be Abundant, Long-lived, Highly Detectable, and Unambiguous

Wright,

Haqq-Misra,

Frank

et al. 2022

Preprint

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The intuition suggested by the Drake Equation implies that technology should be less prevalent than biology in the galaxy. However, it has been appreciated for decades in the SETI community that technosignatures could be more abundant, longer-lived, more detectable, and less ambiguous than biosignatures.We collect the arguments for and against technosignatures' ubiquity, and discuss the implications of some properties of technological life that fundamentally differ from non-technological life, in the context of modern astrobiology: it can spread among the stars to many sites, it can be more easily detected at large distances, and it can produce signs that are unambiguously technological.As an illustration in terms of the Drake Equation, we consider two Drake-like equations, for technosignatures (calculating N (tech)) and biosignatures (calculating N (bio)). We argue that Earth and humanity may be poor guides to the longevity term L, and that its maximum value could be very large, in that technology can outlive its creators and even its host star. We conclude that while the Drake equation implies that N (bio) N (tech), it is also plausible that N (tech) N (bio). As a consequence, as we seek possible indicators of extraterrestrial life, for instance via characterization of the atmospheres of habitable exoplanets, we should search for both biosignatures and technosignatures. This exercise also illustrates ways in which biosignature and technosignature searches can complement and supplement each other, and how methods of technosignature search, including old ideas from SETI, can inform the search for biosignatures and life generally.

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Section: Discussionmentioning

confidence: 99%

The Case for Technosignatures: Why They May Be Abundant, Long-lived, Highly Detectable, and Unambiguous

Wright,

Haqq-Misra,

Frank

et al. 2022

Preprint

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“…Values for the fixed age required for sustained habitability range in the literature from 2 Gyr to 4 Gyr (Truitt et al 2020). If one were to select 2 Gyr as the habitable duration required to host biosignatures, then H would have the functional form:…”

Section: Relative Biosignature Yield Metricsmentioning

confidence: 99%

Potential Habitability as a Stellar Property: Effects of Model Uncertainties and Measurement Precision

Tuchow,

Wright

2021

Preprint

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Knowledge of a star's evolutionary history combined with estimates of planet occurrence rates allows one to infer its relative quality as a location in the search for biosignatures, and to quantify this intuition using long-term habitability metrics. In this study, we analyse the sensitivity of the biosignature yield metrics formulated by Tuchow & Wright (2020) to uncertainties in observable stellar properties and to model uncertainties. We characterize the uncertainties present in fitting a models to stellar observations by generating a stellar model with known properties and adding synthetic uncertainties in the observable properties. We scale the uncertainty in individual observables and observe the the effects on the precision of properties such as stellar mass, age, and our metrics. To determine model uncertainties we compare four well accepted stellar models using different model physics and see how they vary in terms of the values of our metrics. We determine the ability of future missions to rank target stars according to these metrics, given the current precision to which host star properties can be measured. We show that obtaining independent age constraints decreases both the model and systematic uncertainties in determining these metrics and is the most powerful way to improve assessments of the long-term habitability of planets around low mass stars.

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“…The coefficients encapsulate underlying assumptions of the atmospheric modeling and the weather on the planet, as well as of the properties of the surface of the planet and other unknown planet properties that are beyond the scope of this, and indeed most, papers. We found that there is a lack of general consensus in the literature as to what these parameters should be, and an overall disagreement in the models that should be applied (e.g., Kokaia et al 2020;Truitt et al 2020 Abe et al 2011). In choosing our model parameters for the Really Habitable Zone, we therefore followed what appears to be standard practice, and made-up new coefficients entirely as shown in Table 1 according to our whims.…”

Section: Determining the Really Habitable Zonementioning

confidence: 99%

Defining the Really Habitable Zone

Pedbost,

Pomalgu,

Lintott

et al. 2020

Preprint

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Since the discovery of the first confirmed exoplanet, observations have revealed a remarkable diversity of worlds. A wide variety of orbital and physical characteristics are detected in the exoplanet population, and much work has been devoted to deciding which of these planets may be suitable for life. Until now, though, little work has been devoted to deciding which of the potentially habitable planets might actually be worth existing on. To this end, we present the Really Habitable Zone (RHZ), defined as the region around a star where acceptable gins and tonic are likely to be abundant. In common with much of the work in the field, we rely throughout on assumptions which are difficult if not impossible to test and present some plots which astronomers can use in their own talks, stripped of all caveats. We suggest that planets in the Really Habitable Zone be early targets for the JWST, because by the time that thing finally launches we're all going to need a drink.

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A Flexible Bayesian Framework for Assessing Habitability with Joint Observational and Model Constraints

Cited by 18 publications

References 80 publications

The Case for Technosignatures: Why They May Be Abundant, Long-lived, Highly Detectable, and Unambiguous

The Case for Technosignatures: Why They May Be Abundant, Long-lived, Highly Detectable, and Unambiguous

Potential Habitability as a Stellar Property: Effects of Model Uncertainties and Measurement Precision

Defining the Really Habitable Zone

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