Planets

Blog about planets.

The 3D structure of the atmosphere of the exoplanet Tylos

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Two articles, one published in the journal “Nature” and one in the journal “Astronomy & Astrophysics”, report the results of two studies of the exoplanet WASP-121b, officially named Tylos, which describe different aspects of its very turbulent atmosphere. Two teams of researchers with several members in common used the ESPRESSO instrument mounted on ESO’s VLT (Very Large Telescope) in Chile exploiting the combination of the four telescopes to examine the atmosphere of Tylos during a complete transit in front of its star. The result was a mapping of the layers of the atmosphere and the detection of traces of various chemical elements including sodium, iron, and titanium.

Scheme of the the HD 20794 system with its habitable zone in green (Image courtesy Gabriel Pérez (IAC))

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An article published in the journal “Astronomy & Astrophysics” reports the identification of the exoplanet that was cataloged as HD 20794 d. A team of researchers used data collected in more than twenty years with two spectrographs: ESPRESSO, mounted on the VLT, and HARPS, at the La Silla Observatory, both of ESO in Chile, to identify HD 20794 d and define its orbit and characteristics. The analysis indicates that it’s a super-Earth with a mass almost six times the Earth’s with a highly elliptical orbit that brings it into the habitable zone of its star system for part of its year.

Some Martian mounds (Image ESA/ TGO/ CaSSIS)

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An article published in the journal “Nature Geoscience” reports a study on the mounds in Mawrth Vallis, a valley on the planet Mars considered very interesting for the traces of the ancient presence of liquid water. A team of researchers from the Open University and the Natural History Museum in London used data collected by various space probes to perform geomorphological and spectroscopic analyses of the mounds. Their conclusions are that they’re the remains that were formed by erosion by the retreat of the plateau in the Noachian period, between 4.1 and 3.7 billion years ago. For this reason, they believe that they constitute a sort of stratigraphic record of the changes in the presence of water in Mawrth Vallis.

The Australe Scopuli region on Mars (Image ESA/DLR/FU Berlin (CC-BY-SA 3.0 IGO))

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ESA has published reprocessed images of the Australe Scopuli region of Mars captured by its Mars Express space probe’s High Resolution Stereo Camera (HRSC). The area is covered in what appears to be snow but is actually carbon dioxide ice and dust. Despite the differences, the view is reminiscent of a Christmas landscape, especially the kind common at altitudes where it normally snows on Earth. It’s still a significant day because, on December 25, 2003, Mars Express entered Mars’ orbit.

The NGC 346 cluster with 10 circled stars surrounded by protoplanetary disks (Image NASA, ESA, CSA, STScI, O. C. Jones (UK ATC), G. De Marchi (ESTEC), M. Meixner (USRA))

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An article published in “The Astrophysical Journal” reports the results of the study of a group of protoplanetary disks with an age of up to 30 million years, even 10 times older than current models of planet formation predict. A team led by Guido De Marchi of ESA’s European Space Research and Technology Centre used observations conducted with the James Webb space telescope of the cluster NGC 346, in the Small Magellanic Cloud. That region is characterized by a limited amount of elements heavier than hydrogen and helium, just like the early universe. This study confirms that in those conditions, protoplanetary disks can last much longer than astronomers thought.