THE CHEMICAL COMPOSITION OF<i>τ</i>CETI AND POSSIBLE EFFECTS ON TERRESTRIAL PLANETS

Pagano, Michael; Truitt, Amanda; Young, Patrick; Shim, Sang‐Heon

doi:10.1088/0004-637x/803/2/90

Cited by 42 publications

(16 citation statements)

References 58 publications

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“…We consider planet (f) as more solidly dwelling in the habitable zone of Tau Ceti (red) with P =0.370, but it still has a relatively low posterior probability for long-term habitability (in terms of the CHZ 2 ) due to the fact that (f) has likely only recently entered the habitable zone. These calculations confirm the result of Pagano et al (2015), who noted that planet (e) would be considered to be in the habitable zone only with very optimistic assumptions. Planet (f) would initially appear to be a somewhat more robust candidate as a potentially habitable exoplanet, but the associated stellar evolution track shows that due to the increased luminosity of Tau Ceti over its MS lifetime, it is likely the planet has only recently moved into the star's conservative habitable zone.…”

Section: Some Of the Sub-panel Plots Insupporting

confidence: 86%

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

Truitt

Young

Walker

et al. 2020

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The catalog of stellar evolution tracks discussed in our previous work is meant to help characterize exoplanet host-stars of interest for follow-up observations with future missions like JWST. However, the utility of the catalog has been predicated on the assumption that we would precisely know the age of the particular host-star in question; in reality, it is unlikely that we will be able to accurately estimate the age of a given system. Stellar age is relatively straightforward to calculate for stellar clusters, but it is difficult to accurately measure the age of an individual star to high precision. Unfortunately, this is the kind of information we should consider as we attempt to constrain the long-term habitability potential of a given planetary system of interest. This is ultimately why we must rely on predictions of accurate stellar evolution models, as well a consideration of what we can observably measure (stellar mass, composition, orbital radius of an exoplanet) in order to create a statistical framework wherein we can identify the best candidate systems for follow-up characterization. In this paper we discuss a statistical approach to constrain long-term planetary habitability by evaluating the likelihood that at a given time of observation, a star would have a planet in the 2 Gy continuously habitable zone (CHZ 2 ). Additionally, we will discuss how we can use existing observational data (i.e. data assembled in the Hypatia catalog and the Kepler exoplanet host star database) for a robust comparison to the catalog of theoretical stellar models.

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Section: Some Of the Sub-panel Plots Insupporting

confidence: 86%

“…The Tau Ceti exoplanets were chosen specifically as a follow-up investigation to the work done in Pagano et al (2015). In Figure 9, P (CHZ 2 |Z, M ) for planet (e) of the Tau Ceti system (blue) is P =0, since the planet is quite close-in to the star.…”

Section: Some Of the Sub-panel Plots Inmentioning

confidence: 99%

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

Truitt

Young

Walker

et al. 2020

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“…HD 10700 (τ Ceti) is a nearby G-type star, believed to be very similar to our Sun, at a distance of 3.7 pc with an estimated age of 7650 Myr, but with an uncertainty in the range 6130 to 8500 Myr (Pagano et al 2015). The SONS 850 µm image shows a peak in emission at the stellar position with a flux density of 4.4 ± 0.6 mJy ( Fig.…”

Section: τ Ceti (Hd 10700)mentioning

confidence: 86%

SONS: The JCMT legacy survey of debris discs in the submillimetre

Holland

Matthews

Kennedy

et al. 2017

Monthly Notices of the Royal Astronomical Society

126

111

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Debris discs are evidence of the ongoing destructive collisions between planetesimals, and their presence around stars also suggests that planets exist in these systems. In this paper, we present submillimetre images of the thermal emission from debris discs that formed the SCUBA-2 Observations of Nearby Stars (SONS) survey, one of seven legacy surveys undertaken on the James Clerk Maxwell telescope between 2012 and 2015. The overall results of the survey are presented in the form of 850 µm (and 450 µm, where possible) images and fluxes for the observed fields. Excess thermal emission, over that expected from the stellar photosphere, is detected around 49 stars out of the 100 observed fields. The discs are characterised in terms of their flux density, size (radial distribution of the dust) and derived dust properties from their spectral energy distributions. The results show discs over a range of sizes, typically 1-10 times the diameter of the Edgeworth-Kuiper Belt in our Solar System. The mass of a disc, for particles up to a few millimetres in size, is uniquely obtainable with submillimetre observations and this quantity is presented as a function of the host stars' age, showing a tentative decline in mass with age. Having doubled the number of imaged discs at submillimetre wavelengths from ground-based, single dish telescope observations, one of the key legacy products from the SONS survey is to provide a comprehensive target list to observe at high angular resolution using submillimetre/millimetre interferometers (e.g., ALMA, SMA).

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“…Arizona State University (ASU): The ASU analysis was done using the CoG method of stellar abundance determination, relying on the 2014 version of the MOOG radiative transfer code. A previously created script was used to run through all of the steps, then edited to meet the requirements and line list for this study (Pagano et al 2015(Pagano et al , 2016. The stellar atmospheres were calculated through ATLAS9 grid model atmospheres (Castelli & Kurucz 2003) via the MSPAWN72 script.…”

Section: Appendix A: Techniques In the Fieldmentioning

confidence: 99%

A Comparison of Stellar Elemental Abundance Techniques and Measurements

Hinkel

Young

Pagano

et al. 2016

ApJS

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Stellar elemental abundances are important for understanding the fundamental properties of a star or stellar group, such as age and evolutionary history, as well as the composition of an orbiting planet. However, as abundance measurement techniques have progressed, there has been little standardization between individual methods and their comparisons. As a result, different stellar abundance procedures determine measurements that vary beyond quoted error for the same elements within the same stars (Hinkel et al. 2014). The purpose of this paper is to better understand the systematic variations between methods and offer recommendations for producing more accurate results in the future. We have invited a number of participants from around the world (Australia, Portugal, Sweden, Switzerland, and USA) to calculate ten element abundances (C, O, Na, Mg, Al, Si, Fe, Ni, Ba, and Eu) using the same stellar spectra for four stars (HD 361, HD 10700, HD 121504, HD 202206). Each group produced measurements for each of the stars using: 1) their own autonomous techniques, 2) standardized stellar parameters, 3) standardized line list, and 4) both standardized parameters and line list. We present the resulting stellar parameters, absolute abundances, and a metric of data similarity that quantifies homogeneity of the data. We conclude that standardization of some kind, particularly stellar parameters, improves the consistency between methods. However, because results did not converge as more free parameters were standardized, it is clear there are inherent issues within the techniques that need to be reconciled. Therefore, we encourage more conversation and transparency within the community such that stellar abundance determinations can be reproducible as well as accurate and precise.

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THE CHEMICAL COMPOSITION OFτCETI AND POSSIBLE EFFECTS ON TERRESTRIAL PLANETS

Cited by 42 publications

References 58 publications

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

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

SONS: The JCMT legacy survey of debris discs in the submillimetre

A Comparison of Stellar Elemental Abundance Techniques and Measurements

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