TRAPPIST-1

Do the TRAPPIST-1 Planets Have Hydrogen-rich Atmospheres?

Do the TRAPPIST-1 Planets Have Hydrogen-rich Atmospheres?

Recently, transmission spectroscopy in the atmospheres of the TRAPPIST-1 planets revealed flat and featureless absorption spectra, which rule out cloud-free hydrogen-dominated atmospheres. Earth-sized planets orbiting TRAPPIST-1 likely have either a clear or a cloudy/hazy hydrogen-poor atmosphere.

Radiation

Rotifer Studies In Space

Rotifer Studies In Space

With the spacewalk season on hold until next year, ESA astronaut Luca Parmitano took his time to prepare the orbital home for new, tiny and incredibly resistant passengers. Rotifers, commonly called wheel animals, are usually less than a millimetre in size and usually found in fresh water and moist soil.

Mars

New Map Of Water Ice on Mars

New Map Of Water Ice on Mars

A new paper published in Geophysical Research Letters will help by providing a map of water ice believed to be as little as an inch (2.5 centimeters) below the surface.

Analog Studies

Experts on Earth Could Support Astronaut-Scientists on Mars, if They Team Up from the Start

Experts on Earth Could Support Astronaut-Scientists on Mars, if They Team Up from the Start

A scene that first played out on the Moon in 1972 happened again, years later, in Hawaii. While exploring the lunar surface, Apollo 17 astronaut and geologist Harrison Schmitt spotted some bright orange soil - an important clue about the Moon's volcanic history. You can hear the excitement in his voice in recordings, but mission control in Houston couldn't see what was so remarkable in the video beamed back to Earth.

Habitable Zones & Global Climate

Climate Bistability Of Earth-like Exoplanets

Climate Bistability Of Earth-like Exoplanets

Before about 500 million years ago, most probably our planet experienced temporary snowball conditions, with continental and sea ices covering a large fraction of its surface.

Astrochemistry

Mass-Metallicity Trends in Transiting Exoplanets from Atmospheric Abundances of H2O, Na, and K

Mass-Metallicity Trends in Transiting Exoplanets from Atmospheric Abundances of H2O, Na, and K

Atmospheric compositions can provide powerful diagnostics of formation and migration histories of planetary systems.

Astrochemistry

Searching For Water Ice In The Coma Of Interstellar Object 2I/Borisov

Searching For Water Ice In The Coma Of Interstellar Object 2I/Borisov

Interstellar Objects (ISO) passing through our Solar System offer a rare opportunity to probe the physical and chemical processes involved in solid body and planet formation in extrasolar systems.

Extrasolar Planets

Water Is Common Yet Scarce In Exoplanets

Water Is Common Yet Scarce In Exoplanets

The most extensive survey of atmospheric chemical compositions of exoplanets to date has revealed trends that challenge current theories of planet formation and has implications for the search for water in the solar system and beyond.

Habitable Zones & Global Climate

Breathing New Life Into The Rise Of Oxygen Debate

Breathing New Life Into The Rise Of Oxygen Debate

New research strongly suggests that the distinct 'oxygenation events' that created Earth's breathable atmosphere happened spontaneously, rather than being a consequence of biological or tectonic revolutions.

Plant Biology

Constraints on Aquatic Photosynthesis for Terrestrial Planets Around Other Stars

Constraints on Aquatic Photosynthesis for Terrestrial Planets Around Other Stars

Aquatic photosynthesis plays a major role in carbon fixation and O2 production on Earth. In this paper, we analyze the prospects for oxygenic photosynthesis in aquatic environments on Earth-analogs around F-, G-, K- and M-type stars.

Astrochemistry

Origin Of Earth's Water: Sources And Constraints

Origin Of Earth's Water: Sources And Constraints

We review the state of knowledge on the origin of Earth's water. Empirical constraints come from chemical and isotopic measurements of solar system bodies and of Earth itself. Dynamical models have revealed pathways for water delivery to Earth during its formation; most are anchored to specific models for terrestrial planet formation.

More top stories from December.