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doi:10.1086/509283

Cited by 19 publications

(6 citation statements)

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“…We assume that CI and CO are segregated, with CI mainly present in a surface layer surrounding the CO gas, creating optimal shielding (analogous to assuming negligible vertical diffusion; Marino et al 2022). In addition, we update EXOGAS such that the release rate of CO gas is also inversely proportional to the orbital period (  S µ S W + CO dust 2 K , with Ω K the Keplerian frequency; Wyatt et al 2007). This enhances the CO release at smaller radii.…”

Section: Co Gas Distributionmentioning

confidence: 99%

ALMA Observations of the HD 110058 Debris Disk

Hales

Marino

Sheehan

et al. 2022

ApJ

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We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the young, gas-rich debris disk around HD 110058 at 0.″3–0.″6 resolution. The disk is detected in the 0.85 and 1.3 mm continuum, as well as the J = 2–1 and J = 3–2 transitions of 12CO and 13CO. The observations resolve the dust and gas distributions and reveal that this is the smallest debris disk around stars of similar luminosity observed by ALMA. The new ALMA data confirm the disk is very close to edge-on, as shown previously in scattered-light images. We use radiative transfer modeling to constrain the physical properties of dust and gas disks. The dust density peaks at around 31 au and has a smooth outer edge that extends out to ∼70 au. Interestingly, the dust emission is marginally resolved along the minor axis, which indicates that it is vertically thick if truly close to edge-on with an aspect ratio between 0.13 and 0.28. We also find that the CO gas distribution is more compact than the dust (similar to the disk around 49 Ceti), which could be due to a low viscosity and a higher gas release rate at small radii. Using simulations of the gas evolution taking into account the CO photodissociation, shielding, and viscous evolution, we find that HD 110058's CO gas mass and distribution are consistent with a secondary origin scenario. Finally, we find that the gas densities may be high enough to cause the outward drift of small dust grains in the disk.

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Section: Co Gas Distributionmentioning

confidence: 99%

ALMA Observations of the HD 110058 Debris Disk

Hales

Marino

Sheehan

et al. 2022

ApJ

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“…Middle right: Post-impact planet transmission spectra 100 kyr (blue) and 10 Myr (orange) after the impact, with atmospheric properties chosen to match those described by Zahnle et al (2020) for a Hadean Earth. Bottom: Model TRAPPIST-1e with an atmosphere to emulate an early epoch of Earth history (Kaltenegger et al 2007).…”

Section: Resultsmentioning

confidence: 99%

“…Observations suggest that these planets do not possess hydrogen-rich atmospheres (De Wit et al 2018). Therefore we include an additional model exoplanet, with planetary properties based on TRAPPIST-1e and the atmospheric composition based on a potential early epoch of Earth history (see Kaltenegger et al 2007;Rugheimer et al 2015).…”

Section: Background Atmospheresmentioning

confidence: 99%

“…In order to explore both the high-mean-molecularweight atmosphere of early Earth and the TRAPPIST-1 system, we simulate surveys of 5-100 transits around M8V star TRAPPIST-1 at spectral resolution R = 100 (each with 10 hr of out of transit observation). The noise we obtain from this is used to calculate detection thresholds with a varying number of transits for our model TRAPPIST-1e, with a high-meanmolecular-weight 90% N 2 10% CO 2 atmosphere to simulate the atmosphere of the early Earth (Kaltenegger et al 2007;Rugheimer et al 2015). We use a 10 ppm systematic noise floor for our high intensity regimes, which is approached but not reached at any point, even for 100 transits.…”

Section: Alternative Observational Regimesmentioning

confidence: 99%

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Prebiosignature Molecules Can Be Detected in Temperate Exoplanet Atmospheres with JWST

Claringbold,

Rimmer,

Rugheimer

et al. 2023

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The search for biosignatures on exoplanets connects the fields of biology and biochemistry to astronomical observation, with the hope that we might detect evidence of active biological processes on worlds outside the solar system. Here we focus on a complementary aspect of exoplanet characterization connecting astronomy to prebiotic chemistry: the search for molecules associated with the origin of life, prebiosignatures. Prebiosignature surveys in planetary atmospheres offer the potential to both constrain the ubiquity of life in the galaxy and provide important tests of current prebiotic syntheses outside of the laboratory setting. Here, we quantify the minimum abundance of identified prebiosignature molecules that would be required for detection by transmission spectroscopy using JWST. We consider prebiosignatures on five classes of terrestrial planets: an ocean planet, a volcanic planet, a post-impact planet, a super-Earth, and an early-Earth analog. Using a novel modeling and detection test pipeline, with simulated JWST noise, we find the detection thresholds of hydrogen cyanide ( HCN ), hydrogen sulfide (H2S), cyanoacetylene (HC3N), ammonia (NH3), methane (CH4), acetylene (C2H2), sulfur dioxide (SO2), nitric oxide (NO), formaldehyde (CH2O), and carbon monoxide (CO) in a variety of low-mean-molecular-weight (<5) atmospheres. We test the dependence of these detection thresholds on an M dwarf target star and the number of observed transits, finding that a modest number of transits (1–10) are required to detect prebiosignatures in numerous candidate planets, including TRAPPIST-1e with a high-mean-molecular-weight atmosphere. We find that the Near Infrared Spectrograph G395M/H instrument is best suited for detecting most prebiosignatures.

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“…The UV band (∼0.2-0.4 μm) provides a promising means of detecting these species owing to their strong absorption in this wavelength range. In the solar system, Earth's atmosphere exhibits strong O 2 and O 3 absorption bands in the UV region (e.g., Turnbull et al 2006;Kaltenegger et al 2007), which have played a significant role in shaping the planet's ability to be a life-bearing world.…”

Section: Introductionmentioning

confidence: 99%

Reflected Spectroscopy of Small Exoplanets. III. Probing the UV Band to Measure Biosignature Gases

Damiano,

Hu,

Mennesson

2023

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Direct-imaging observations of terrestrial exoplanets will enable their atmospheric characterization and habitability assessment. Considering Earth, the key atmospheric signatures for the biosphere are O2 and the photochemical product O3. However, this O2–O3 biosignature is not detectable in the visible wavelengths for most of the time after the emergence of oxygenic photosynthesis life (i.e., Proterozoic Earth). Here we demonstrate spectroscopic observations in the ultraviolet wavelengths for detecting and characterizing O2 and O3 in Proterozoic-Earth-like planets, using ExoReL R . For an O2 mixing ratio 2–3 orders of magnitude less than the present-day Earth and an O3 mixing ratio of 10−7 to 10−6, we find that O3 can be detected and its mixing ratio can be measured precisely (within 1 order of magnitude) in the ultraviolet (0.25–0.4 μm), in addition to visible-wavelength spectroscopy. With modest spectral resolution (R = 7) and signal-to-noise ratio (∼10) in the ultraviolet, the O3 detection is robust against other potential gases absorbing in the ultraviolet (e.g., H2S and SO2), as well as the short-wavelength cutoff between 0.2 and 0.25 μm. While the O3 detection does not rely on the near-infrared spectra, extending the wavelength coverage to the near-infrared (1–1.8 μm) would provide essential information to interpret the O3 biosignature, including the mixing ratio of H2O, the cloud pressure, and the determination of the dominant gas of the atmosphere. The ultraviolet and near-infrared capabilities should thus be evaluated as critical components for future missions aiming at imaging and characterizing terrestrial exoplanets, such as the Habitable Worlds Observatory.

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Untitled

Cited by 19 publications

References 0 publications

ALMA Observations of the HD 110058 Debris Disk

ALMA Observations of the HD 110058 Debris Disk

Prebiosignature Molecules Can Be Detected in Temperate Exoplanet Atmospheres with JWST

Reflected Spectroscopy of Small Exoplanets. III. Probing the UV Band to Measure Biosignature Gases

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