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Saturn's Moon Mimas May Harbor an Internal Ocean | Planetary News – Planetary News

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A new study suggests that an ocean might lurk below the heavily cratered, seemingly inactive surface of Saturn’s moon Mimas. Credit: Cassini Imaging Team/ISS/JPL/ESA/NASA.

Saturn’s moon Mimas may be the newest, if not the most unlikely member of the solar system’s family of icy bodies, with internal liquid water oceans according to a new study by Alyssa Rose Rhoden of the Southwest Research Institute and Matthew E. Walker of the Planetary Science Institute. These bodies, which include Europa, Enceladus, and possibly Pluto and Triton, are all considered prime targets for exploration due to their ability to maintain potentially life-sustaining water under their outer ice shells at a wide range of distances from the Sun.

What makes Mimas unusual is what it lacks in comparison with all other known ocean-bearing moons: active geology. Mimas is small (less than 400 kilometers-in-diameter) and heavily cratered, suggesting that it has remained frozen and geologically inactive for many millions of years despite the powerful tidal forces it experiences as it orbits Saturn. Observations made by the Cassini spacecraft of Mimas’ orbital libration, or variation in its tilt over time, suggested that either its core was irregularly shaped or that an internal ocean could exist. For Mimas to maintain an internal ocean, but have an ice shell thick enough to remain frozen, would require a careful balance of tidal heating, as its small size means it would quickly lose any heat that is produced.  

Rhodes and Walker used tidal heating models to find the balance between these two constraints and found that an ice shell between 24 and 31 kilometers thick produced a good fit for the data. Because the thickness of the ice shell is related to the surface heat flux, a future mission with an instrument similar to Juno’s microwave radiometer could verify this finding. The confirmation of an ocean on such an unlikely world would greatly expand our understanding of how prevalent these important ocean moons may be in the solar system and beyond. READ MORE

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NASA: Contact lost with spacecraft on way to test moon orbit – Hamilton Spectator

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WASHINGTON (AP) — NASA said Tuesday it has lost contact with a $32.7 million spacecraft headed to the moon to test out a lopsided lunar orbit, but agency engineers are hopeful they can fix the problem.

After one successful communication and a second partial one on Monday, the space agency said it could no longer communicate with the spacecraft called Capstone. Engineers are trying to find the cause of the communications drop-off and are optimistic they can fix it, NASA spokesperson Sarah Frazier said Tuesday.

The spacecraft, which launched from New Zealand on June 28, had spent nearly a week in Earth orbit and had been successfully kick-started on its way to the moon, when contact was lost, Frazier said.

The 55-pound satellite is the size of a microwave oven and will be the first spacecraft to try out this oval orbit, which is where NASA wants to stage its Gateway outpost. Gateway would serve as a staging point for astronauts before they descend to the lunar surface.

The orbit balances the gravities of Earth and the moon and so requires little maneuvering and therefore fuel and allows the satellite — or a space station — to stay in constant contact with Earth.

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My Thesis in 400 Words: Anne Boucher | Institute for Research on Exoplanets – News | Institute for Research on Exoplanets

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Anne Boucher, an iREx student at the Université de Montréal, submitted her doctoral thesis at the end of 2021. She summarises the research project she carried out as part of her Ph.D here.

During my Ph.D, I became interested in the atmosphere of gas giant exoplanets that orbit very close to their star. Thanks to a technique called transmission spectroscopy, I studied the chemical composition of their atmosphere, which gives a lot of information on their formation and evolution mechanisms. The detailed study of these exoplanets, which we sometimes call hot Jupiters or hot sub-Saturns, provides a better understanding of the physical, chemical, and dynamical processes that govern the atmosphere of these celestial objects.

I mainly used data from the SPIRou instrument, a high-resolution spectropolarimeter that operates in the near infrared and is installed at the Canada-France-Hawaii Telescope. We first observed HD 189733 b, one of the most studied exoplanets, to build the analysis codes. By exploiting transit spectroscopy, we were able to confirm the presence of water and determine its abundance. The results obtained, consistent with previous studies, indicate that the atmosphere of HD 189733 b is relatively clear (free of clouds) and that the planet likely formed far from its star, where it is cold enough to find water in the form of ice. A strong blueshift of water absorption was observed, which could be a consequence of the presence of strong winds in the atmosphere.

Artistic representation of the exoplanet HD 189733 b, credit :  NASA, ESA, and G. Bacon (STScI)

Next, we studied WASP-127 b, a less massive exoplanet, but much larger than Saturn. A recent study of data from the Hubble Space Telescope (HST) and the Spitzer Space Telescope could not differentiate between two atmospheric scenarios: a low carbon-to-oxygen (C/O) ratio with little carbon monoxide (CO), or a high ratio with a lot of CO. As this ratio helps to determine how a planet was formed, we decided to use SPIRou, which makes it possible to observe a band of CO not observable with HST and Spitzer. We were able to determine that there was very little CO and a very low C/O, which has rarely been observed, but which is supported by some more realistic training scenarios that vary over time. The SPIRou data also confirmed the presence of water and suggests that, if confirmed, there could even be hydroxyl (OH): an unexpected detection since the exoplanet is so cold.

This work has allowed to develop the expertise of the Université de Montréal in high resolution near-infrared transit spectroscopy, in particular with SPIRou, allowing to explore the atmospheric conditions of hot Jupiters and sub-Saturns. This first joint analysis made on high and low resolution transmission data allowed to obtain better constraints on the atmospheric parameters. This method is proving to be a very powerful tool for the study of atmospheres and will be even more so with the revolutionary capabilities of JWST.

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Anne worked on her Ph.D. at the Université de Montréal between 2016 and 2022, under the supervision of David Lafrenière. Her thesis will soon be available.

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Nicolas Cowan, Finalist for the 2021 Relève scientifique Prize – News | Institute for Research on Exoplanets

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Nicholas Cowan. Credit: McGill University.

Nicolas Cowan, Professor at McGill University and a member of both iREx and the McGill Space Institute, is one of the finalists for the Relève Scientifique du Québec 2021 Prize, an award which aims to highlight the commitment and excellence in research of a person 40 years of age or younger.

Nick has been a Professor in the Departments of Physics and Earth and Planetary Sciences at McGill University since 2015. He specialises in astrobiology and mainly studies the surface and atmosphere of exoplanets. He is particularly interested in the climate of these planets found outside of our Solar System.

The researcher mainly uses space- and ground-based telescopes to collect and analyse data which he uses to study the characteristics of various exoplanets. More specifically, the data seeks to measure the reflection of clouds, detect the presence of greenhouse gases via the infrared signature of the atmosphere, and heat transport, i.e. the winds. These data are used to create maps of the surface and the temperature of exoplanets, a method commonly referred to as exo-cartography. The study of the exoplanets’ climate also allows us to learn a lot about that of our planet, Earth.

Nick’s commitment to the research community is illustrated in particular by his participation in numerous NASA and Canadian Space Agency committees to promote the study of planetary climates and to contribute to the planning of future space missions to study exoplanets.

In addition to his work as a researcher, Nick is also involved in the Astronomy in Indigenous Communities program, which aims to attract Indigenous youth to pursue a career in STEM.

It is with pride that the iREx congratulates Nicolas Cowan for this distinction.

About the Relève scientifique du Québec Prize

The Relève scientifique du Québec prize is awarded to a person aged 40 or under who has distinguished themselves by the excellence of their research and who demonstrates the ability to establish and maintain constructive and lasting links with the research community. All disciplines are recognised for this award. Each year one recipient and two finalists are selected.

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