Planets

Blog about planets.

A graph with the conservative habitable zone illustrated by the orange band and ellipses illustrating the extended habitable zone proposed by this study

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An article published in “The Astrophysical Journal” reports the results of a study on the habitable zone that goes beyond the so-called conservative zone because it’s based on rigid assumptions. Astrophysicist Amri Wandel of the Hebrew University of Jerusalem focused on examining the conditions existing in systems of low-mass stars: orange dwarfs (K-class stars) and red dwarfs (M-class stars). The study specifically considered planets tidally locked to their stars.

Amri Wandel conducted an analysis using climate models that account for global heat transport, the greenhouse effect, and albedo. This led him to conclude that these stars may host planets potentially habitable for Earth-like life forms orbiting outside the conservative habitable zone.

Artist's concept of the of the exoplanet PSR J2322-2650b and its pulsar (Image NASA, ESA, CSA, Ralf Crawford (STScI))

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An article published in The Astrophysical Journal Letters reports the results of a study of a gas giant exoplanet cataloged as PSR J2322-2650b, which has a completely abnormal atmosphere composed above all of helium and carbon. A team of researchers used observations conducted with the James Webb Space Telescope to study the atmosphere of this exoplanet, which has a mass similar to Jupiter’s and has a distance from its star that is only one-hundredth of the Earth’s distance from the Sun. The star is a pulsar, adding another unusual element to the system. PSR J2322-2650b can’t be explained by current models of planetary formation.

Some views of the rock Cheyava Falls with spectroscopic results (d) from the examination of samples from the area

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An article published in the journal “Nature” reports the results of the analysis of data collected by NASA’s Mars Rover Perseverance on the rock nicknamed Cheyava Falls. Perseverance found it in 2024 in the Neretva Valley during its journey within the Jezero Crater on Mars. The rock immediately attracted great interest because it contains chemical signatures and structures that could have been generated by ancient Martian life forms.

A team of researchers confirmed the exciting results presented last year and concluded that these are potential biosignatures. This means they provide clues to the possible presence of Martian life forms in the past, but further studies are needed to obtain definitive answers. In fact, the presence of organic compounds and iron minerals such as vivianite and greigite could also be due to abiotic reactions.

The Alpha Centauri system as seen by the James Webb Space Telescope on the left, a zoom of the two main stars in the center, and a further zoom on the right indicating the exoplanet candidate designated as S1.

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Two articles accepted for publication in “The Astrophysical Journal Letters” report different aspects of the study that led to the possible discovery of a gas giant planet orbiting the star Alpha Centauri A. Astronomers used observations with the James Webb Space Telescope’s MIRI instrument to identify a light source whose characteristics make it a candidate exoplanet. The information gathered suggests it may be a gas planet similar in size to Jupiter, although its mass could be close to Saturn’s. If confirmed, it would be the closest exoplanet orbiting a Sun-like star in its system’s habitable zone.

Arcadia Planitia on Mars

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ESA has published a photo of the Arcadia Planitia region on Mars captured by its Mars Express space probe’s High Resolution Stereo Camera (HRSC). This is an interesting region from a geological point of view because it’s northwest of the large volcanoes of Tharsis, the largest in the entire solar system, and traces of ancient lava flows are still visible. It could be important for the exploration of the red planet if confirmation of the presence of frozen water right under the surface were to arrive.