One of the big stories of the week. Garys sent in the link https://arstechnica.com/science/2023/08/we-dont-understand-how-a-freakishly-heavy-exoplanet-could-have-formed/ … a huge planet, 73 times the mass of the earth, and the size of Neptune, has been discovered. This seems to have appealed to the media. We are told it has a very high density – akin to metal. Ars Technica says as dense as silver, the link at Phys Org says steel. It is situated in proximity to its host star, so close it is probably subject to intense radiation levels. This tends to drive away the planet’s atmosphere – stripping it down to its rocky core. All this has been deduced from telescope data. Its mass, or density, was measured by calculating the gravitational pull of the planet on its host star. The researchers came up with two possibilities – 1] a rocky planet with a thin atmosphere, and 2] evenly distributed between a rock core and a massive coating of water. However, it would not be like water on earth as it is orbiting too close to its host star. See https://doi.org/10.1038/s41586-023-06499-2 …
Gary also sent in another link, https://www.space.com/landslides-mars-water-surrounded-olympus-mons-solar-system-largest-volcano … landslides on Mars suggest water once surrounded Mons Olympus, a big volcanic crater [it is thought]. The claim comes via a digital terrain model as well as high resolution cameras onboard the ESA Mars Express. This new information comes after similar geological evidence found in July – gigantic cliffs surrounding Mons Olympus. The cliffs, or escaprment, may possibly mark an ancient shoreline.
At https://phys.org/news/2023-08-dense-neptune-sized-exoplanet-tess.html … here we look at the Neptune sized planet once again – discovered by using TESS = NASAs Transiting Exoplanet Survey Satellite. TESS has identified a possible 6800 exoplanets [objects of interest]. Some 379 of these have been confirmed. So far.