Terrestrial Planet Archives

Emblematic direct imaging discoveries (not exhaustive): 2M1207 & AB Pic [24,25], RXJ 1609 [26], κ And [27], HR 8799 [28], β Pic [29], HD 95086 b [30], GJ 504 [31], 51 Eri b [32], HIP 65426 b [33], TYC 8998-760-1 b [34], and b Cen b [35]. -- astro-ph.EP

Astrochemistry, Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Gas Giants, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Status Report, Stellar Cartography, Water/Hycean Worlds & Oceanography

Direct Imaging Of Exoplanets: Legacy And Prospects

by Keith CowingApril 18, 2024

Understanding how giant and terrestrial planets form and evolve, what is their internal structure and that of their atmosphere, represents one of the major challenges of modern astronomy, which is […]

We show the transmission spectrum for each reduction in the top panel and the differences between the reductions (in units of sigma) in the bottom panel. All three of our reductions agree per-point, at the ∼2σ level or better, with a median difference of 6ppm. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Status Report

JWST COMPASS: A NIRSpec/G395H Transmission Spectrum Of The Sub-Neptune TOI-836c

by Keith CowingApril 2, 2024

Planets between the sizes of Earth and Neptune are the most common in the Galaxy, bridging the gap between the terrestrial and giant planets in our Solar System.

Left: seasonal variation of the temperature, which is defined by the difference between the Northern Hemisphere (NH) averaged surface temperature and the global annual mean surface temperature. Middle: the maximum streamfunction in NH. Right: The latitude of the maximum zonal mean precipitation (ITCZ). The filled shaded contours represent the results from no-cloud simulations and the values are shown in the colourbars, while the open contours represent the results from cloud simulations and the values are shown in inline labels. For comparison, the contours are plotted at the same levels for no-clouds and clouds simulations. To highlight the difference in seasonal transition, the zero contour lines are bold black (clouds) and gray (no-clouds) for the left and right panels. The contours of streamfunction and ITCZ latitude are smoothed by a Gaussian filter with a standard deviation of σ = 3 days. The horizontal lines represent day of vernal equinox (day 90), northern summer solstice (day 180), and autumnal equinox (day 270), and day 0 is northern winter solstice. The vertical lines represent rotation rates of Ω∗ = 1/8 and 1. -- physics.ao-ph

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Status Report, Water/Hycean Worlds & Oceanography

Clouds And Seasonality On Terrestrial Planets With Varying Rotation Rates

by Keith CowingFebruary 12, 2024February 11, 2024

Using an idealised climate model incorporating seasonal forcing, we investigate the impact of rotation rate on the abundance of clouds on an Earth-like aquaplanet, and the resulting impacts upon albedo […]

Schematic diagram of various outcomes of planet formation when we assume efficient planet formation at pressure bumps. This diagram summarizes the results from Section 2.1 and 3.1. Pressure bumps allow planets to form quickly and at very similar time and location, which leads to pairs or chains of planets with highly similar masses. This leads to intra-similar “SuperEarths” and “Jupiters” whose masses are set by the pebble isolation mass and gas saturation mass, respectively. Meanwhile, planets that form cores slowly (“Earths”) or accrete massive envelopes slowly (“Saturns”) would exhibit less intra-system mass uniformity. -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gas Giants, Jupiter, Saturn, Status Report

Earths Are Not Super-Earths, Saturns Are Not Jupiters: Imprints Of Pressure-bump Planet Formation On Planetary Architectures

by Keith CowingJanuary 14, 2024January 14, 2024

In protoplanetary disks, sufficiently massive planets excite pressure bumps, which can then be preferred locations for forming new planet cores. We discuss how this loop may affect the architecture of […]

atmospheric abundances for Venus, Earth and Mars.

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Imaging & Spectroscopy, Press Release, TRAPPIST-1, Water/Hycean Worlds & Oceanography

A Carbon-lite Atmosphere Could Be A Sign Of Water And Life On Other Terrestrial Planets

by Keith CowingDecember 29, 2023December 29, 2023

Scientists at MIT, the University of Birmingham, and elsewhere say that astronomers’ best chance of finding liquid water, and even life on other planets, is to look for the absence, […]

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

Are There Terrestrial Planets Lurking in the Outer Solar System?

by Keith CowingDecember 15, 2023December 15, 2023

Motivated by recent measurements of the free-floating planet mass function at terrestrial masses, we consider the possibility that the solar system may have captured a terrestrial planet early in its […]

We select 10 and 5 candidate planets around nearby stars for ELT/HARMONI and ELT/METIS, respectively. As the spatial resolution of ELT/HARMONI is smaller than the plotting range, we only show spatial resolution for ELT/METIS as the vertical dotted blue line. Planets located to the right of the dotted line are suitable planets for ELT/METIS. All colored points are suitable planets for ELT/HARMONI. The size of the colored point is proportional to the planet radius. The color of the point is based on the equilibrium temperature. All colored data points are the candidate planets listed in Table 1. Selection criteria can be found in §2.1. The gray points are other exoplanets from NEA that are less suitable for direct imaging with ELT. -- astro-ph.EP

Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Proxima Centauri, Status Report, TRAPPIST-1

Detecting Biosignatures in Nearby Rocky Exoplanets using High-Contrast Imaging and Medium-Resolution Spectroscopy with Extremely Large Telescope

by Keith CowingNovember 30, 2023November 30, 2023

In the upcoming decades, one of the primary objectives in exoplanet science is to search for habitable planets and signs of extraterrestrial life in the universe.

Constraining the surface heterogeneities of a host star. a. A simulated 3.3-d full rotation curve of TRAPPIST-1 (black line) featuring nine transits of six planets (coloured lines). b. A snapshot of the spot distribution at the last rotational phase of the simulation shown in panel a, with the transit chords of planets b, c, d, and e. c. Contaminated transmission spectra for the same transit train of planets b–e (coloured lines). A nominal planet radius of 1 R⊕ (dashed gray line) is used for each planet to ease comparisons of the TLS effect for each planet. d. The residual stellar contamination signals for the simulated transits of planets c–e (coloured lines), after correcting for the TLS effect using the in-transit signal from planet b. A median-subtracted model of an atmosphere (see Figure 2) is shown for comparison (gray dashed line). e. Close-up view of the transit profiles for the four-planet transit train, highlighting repeated occultations of the same active regions by planets b and d as well as c and e, whose transit chords overlap in this simulation. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, TRAPPIST-1

A Roadmap To The Efficient And Robust Characterization Of Temperate Terrestrial Planet Atmospheres With JWST

by Keith CowingNovember 1, 2023November 1, 2023

Ultra-cool dwarf stars are abundant, long-lived, and uniquely suited to enable the atmospheric study of transiting terrestrial companions with JWST. Amongst them, the most prominent is the M8.5V star TRAPPIST-1 […]

The blue, orange, and red crosses represent the averaged RV of stars due to Earth-like planets located at the IHZ, CHZ, and OHZ, respectively. The green crosses represent the maximum RV of Earth-like planets at the IHZ, with an inclination of 90◦ . The right panel shows the histogram of the RV expectation and the CDF. -- astro-ph.EP

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

The Potential of Detecting Nearby Terrestrial Planets in the HZ with Different Methods

by Keith CowingOctober 24, 2023October 24, 2023

Terrestrial planets in the habitable zone around nearby stars are of great interest and provide a good sample for further characteristics of their habitability.

Mercury, Press Release

The Origin Of Mercury’s Structure and Chemical Composition and Their Astrobiological Implications

by Keith CowingOctober 17, 2023October 17, 2023

Mercury can be categorized as either an endmember or an outlier planet due to its unusually large iron core, constituting approximately 70% of its total mass. The origin of this […]

Terrestrial Planet

Direct Imaging Of Exoplanets: Legacy And Prospects

JWST COMPASS: A NIRSpec/G395H Transmission Spectrum Of The Sub-Neptune TOI-836c

Clouds And Seasonality On Terrestrial Planets With Varying Rotation Rates

Earths Are Not Super-Earths, Saturns Are Not Jupiters: Imprints Of Pressure-bump Planet Formation On Planetary Architectures

A Carbon-lite Atmosphere Could Be A Sign Of Water And Life On Other Terrestrial Planets

Are There Terrestrial Planets Lurking in the Outer Solar System?

Detecting Biosignatures in Nearby Rocky Exoplanets using High-Contrast Imaging and Medium-Resolution Spectroscopy with Extremely Large Telescope

A Roadmap To The Efficient And Robust Characterization Of Temperate Terrestrial Planet Atmospheres With JWST

The Potential of Detecting Nearby Terrestrial Planets in the HZ with Different Methods

The Origin Of Mercury’s Structure and Chemical Composition and Their Astrobiological Implications

Miraflores Butte On Mars

Ocean World Exploration: 2026 American Samoa ROV + Mapping Exploration

Development Of An Adaptive Optics Testbed At MPIA For The ELT/Planetary Camera And Spectrograph (PCS)

Exploring Long-period Architectures: Four New Planet Candidates from Kepler with Periods >342 days

The Selfish Ribosome