Earth-like Planet Archives

Schematic view of the four 8.2m Unit Telescopes of the VLT (multi-UT mode) feeding, through the Coude train, the Front-End unit of the ESPRESSO spectrograph located in the Com- ´ bined Coude Laboratory. -- astro-ph.IM

Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

ESPRESSO on VLT: An Instrument For Exoplanet Research

by Keith CowingFebruary 1, 2024February 1, 2024

ESPRESSO (Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations) is a VLT ultra-stable high resolution spectrograph installed at ESO’s Paranal Observatory in Chile at the end of 2017 and […]

Best-fit model from combined fit, showing K2 (top) and TESS data (middle). The three planets are illustrated with different colors. The bottom panel presents phase folds of K2 and TESS data with the transit model. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

The Compact Multi-planet System GJ 9827 Revisited With ESPRESSO

by Keith CowingJanuary 16, 2024January 16, 2024

GJ 9827 is a bright, nearby K7V star orbited by two super-Earths and one mini-Neptune on close-in orbits. The system was first discovered using K2 data and then further characterized […]

The Masses (or M sin i values or mass estimates) vs. semi-major axes of the KGPS-I transiting planets and companions. For systems with a giant planet (M sin i > 0.3 MJ), the circle fill color corresponds to the maximum detected companion mass in the system (capped at 100 Jupiter masses), and the edge color encircling each point corresponds to the planetary system. Black dots correspond to transiting planets in our survey for which giant planets were not detected. Planet masses or M sin i values are reported where they are measured, but mass estimates are used for m ≲ 3 × 10−2MJ (see text for details). Companions that have eccentric, stellar-mass companions at large separations (KOIs 2169 and 3158, yellow) have planets that are smaller and closer to their stars than the typical transiting planets from the KGPS sample, whereas transiting planets that have giant planet companions (non-yellow colors) have comparable sizes and orbits to the transiting planets without detected giant planet companions. -- -- astro-ph.EP "The Kepler Giant Planet Search. I: A Decade of Kepler Planet Host Radial Velocities from W. M. Keck Observatory" -- astro-ph.EP The Kepler Giant Planet Search. I: A Decade of Kepler Planet Host Radial Velocities from W. M. Keck Observatory (older version) -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Astrophysicists Publish Kepler Giant Planet Search, An Aid To “Figure Out Where To Find Life”

by Keith CowingDecember 21, 2023December 21, 2023

A team of astrophysicists led by Lauren Weiss, assistant professor in the Department of Physics and Astronomy at the University of Notre Dame, created the first-ever catalog of small, Earth-like […]

An Earth-like target and a Mi = 3.604 × 1022 kg (Mi/Mt = 0.0063) impactor at the time of contact between the impactor and the target, with (a) the locations of tracer particles within the target and impactor, (b) geotherms under standard and warm mantle conditions (see Appendix A.3), as well as the solidus for our mantle and core materials, and (c) the pre-impact pressure and temperature profiles within the y = 0 km slice of both bodies. -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Comets and Asteroids, Impact events, Meteorites & Asteroids, Status Report

The Distribution Of Impactor Core Material During Large Impacts On Earth-like Planets

by Keith CowingDecember 20, 2023December 20, 2023

Large impacts onto young rocky planets may transform their compositions, creating highly reducing conditions at their surfaces and reintroducing highly siderophile metals to their mantles. Key to these processes is […]

True N2-dominated planet-to-star flux ratio spectrum with an assumed S/N = 20 (red) plotted against 1000 randomly sampled retrieved spectra with 95% confidence intervals. The blue spectrum is the median spectrum created from the 1000 plotted model runs that make up our confidence interval. -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Constraining Background N2 Inventories On Directly Imaged Terrestrial Exoplanets To Rule Out O2 False Positives

by Keith CowingNovember 24, 2023November 24, 2023

Direct imaging spectroscopy with future space-based telescopes will constrain terrestrial planet atmospheric composition and potentially detect biosignature gases. One promising indication of life is abundant atmospheric O2.

Spectral signs of glint in phase-dependent observations of Earth. A full phase spectrum of Earth is corrected to crescent phase using a Lambert phase function (dark blue) and subtracted from a crescent phase spectrum of Earth (black) to produce a difference spectrum (grey). The result is well reproduced in window regions by a model that represents a solar spectrum that experiences Rayleigh scattering opacity (light blue) as it passes twice through the atmosphere and scatters once at the surface. -- astro-ph.EP

Exoplanets, -moons, -comets, Habitable Zones, Status Report, Water/Hycean Worlds & Oceanography

Characterizing Exoplanet Habitability

by Keith CowingNovember 20, 2023November 20, 2023

A habitable exoplanet is a world that can maintain stable liquid water on its surface. Techniques and approaches to characterizing such worlds are essential, as performing a census of Earth-like […]

Mass-radius diagram. The green circles show the exoplanet data from exoplanets.eu, the black stars show the Solar System planets and the blue and orange points show the measured values for TOI-1736 b and TOI-2141 b, respectively. Several models from Zeng et al. (2019) are also plotted for comparison. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

TOI-1736 and TOI-2141: Two Systems Including Sub-Neptunes Around Solar Analogs Revealed By TESS And SOPHIE

by Keith CowingNovember 15, 2023November 15, 2023

Planetary systems around solar analogs inform us about how planets form and evolve in Solar System-like environments. We report the detection and characterization of two planetary systems around the solar […]

Responses of the atmospheric pCH4 to biogenic CH4 flux for the case of F-, G-, and Ktype stars (blue, black, and light blue solid lines with dots) (ExpCH4fluxF2V, ExpCH4fluxG2V, and ExpCH4fluxK2V in Table 3). The dotted lines represent the results of the case of the G-type star with the scaled intensity of the spectra at 200–210 nm (0.1, 0.5, 2, 10, and 40 times for purple, light purple, orange, red, and brown lines, respectively). (ExpCH4flux200nm in Table 3). -- astro-ph.EP

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Status Report

Controls of Atmospheric Methane on Early Earth and Inhabited Earth-like Terrestrial Exoplanets

by Keith CowingNovember 14, 2023November 14, 2023

Methane (CH4) is a primarily biogenic greenhouse gas. As such, it represents an essential biosignature to search for life on exoplanets.

Upper left panel: Comparison of our work to the model results of Mikal-Evans (2022) who assumed a cloud-less Archean-Earth. Grey shading indicated the wavelength range of the figure below. Lower left panel: The transmission spectra of TRAPPIST-1e observed with HST/WFC3 during two different transits (see Zhang et al. 2018). The green lines show our wet alive model results during the Carrington-like event (solid lines - scenario [5], dashed lines - scenario [6]), while the blue lines correspond to the Archean-Earth scenario of Mikal-Evans (2022). Right panel: Comparison of the corresponding assumed atmospheric temperature profiles. -- astro-ph.EP

Exoplanets, -moons, -comets, Imaging & Spectroscopy, Radiation, Space Weather & Heliophysics, Status Report, TRAPPIST-1

Impact of Cosmic Rays on Atmospheric Ion Chemistry and Spectral Transmission Features of TRAPPIST-1e

by Keith CowingNovember 10, 2023November 10, 2023

Ongoing observing projects like the James Webb Space Telescope (JWST) and future missions offer the chance to characterize Earth-like exoplanetary atmospheres. Thereby, M-dwarfs are preferred targets for transit observations, for […]

Boundaries of the Habitable Zone under various climate and atmospheric models as a function of radiative flux received from the host star, relative to Earth. Dashed lines represent the extended boundaries due to subglacial liquid water suggested in this work: blue for the inner HZ boundary (nightside ice evaporates due to heat transport, the percentage marks the global transport parameter f) and violet for the outer one (Martian polar lakes). Solid green lines and green shading denote the conservative HZ boundaries: inner one (moist greenhouse) and outer one (maximum CO2 greenhouse), calculated using the 1-D climate model. Also marked is the recent Venus boundary (dashed green line). The orange curve marks the tidal locking radius. Circles denote the terrestrial planets in the solar system and a few Earth-sized exoplanets orbiting M-dwarf stars. -- Hebrew University of Jerusalem

Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Press Release, Water/Hycean Worlds & Oceanography

Extended Habitability Of Exoplanets Due To Subglacial Water

by Keith CowingNovember 10, 2023November 10, 2023

Professor Amri Wandel, from Hebrew University of Jerusalem, has unveiled research that promises to redefine our comprehension of habitable exoplanets. In a recent study published in the Astronomical Journal, Professor […]

Earth-like Planet

ESPRESSO on VLT: An Instrument For Exoplanet Research

The Compact Multi-planet System GJ 9827 Revisited With ESPRESSO

Astrophysicists Publish Kepler Giant Planet Search, An Aid To “Figure Out Where To Find Life”

The Distribution Of Impactor Core Material During Large Impacts On Earth-like Planets

Constraining Background N2 Inventories On Directly Imaged Terrestrial Exoplanets To Rule Out O2 False Positives

Characterizing Exoplanet Habitability

TOI-1736 and TOI-2141: Two Systems Including Sub-Neptunes Around Solar Analogs Revealed By TESS And SOPHIE

Controls of Atmospheric Methane on Early Earth and Inhabited Earth-like Terrestrial Exoplanets

Impact of Cosmic Rays on Atmospheric Ion Chemistry and Spectral Transmission Features of TRAPPIST-1e

Extended Habitability Of Exoplanets Due To Subglacial Water

Curiosity Mars Rover Discovers A Field Of Honeycomb Textures

Viking Science

Constraining The Lives And Times Of Exoplanets Through Evolutionary Bayesian Retrievals

Project Hephaistos — III. Characterizing Anomalous Infrared Sources Identified As Dyson-sphere Candidates

SCoRE: The Surface Composition Of Rocky Exoplanets