Exoplanets: I’ll Stop the World and Melt With You

By -

Source:  Caleb A. Scharf, Scientific American
Excerpt: Gas giant planets are among the most beautiful and awe-inspiring worlds. …The major bulk of these planets, and their cousins around other stars, consists of primordial hydrogen and helium – vast envelopes of matter cocooning their cores and rendering them inaccessible to us. The pressures deep down in a planet like Jupiter can reach a hundred million times those on Earth’s surface, and temperatures can be tens of thousands of Kelvin. …At such huge pressures, hydrogen becomes a liquid, even though temperatures are high. …A new paper showed up this past week by Wilson and Militzer that suggests … if a gas giant planet forms around a large rocky proto-planet (perhaps 10 times the mass of the Earth), the liquid metallic hydrogen that eventually envelops that core may also melt, or dissolve it. ... bigger, hotter “super-Jupiter” exoplanets may appear more abundant in heavy elements to our astronomical instruments not because they’re getting polluted by in-falling stuff, but because they’ve digested their original cores.

Popular posts from this blog

Stellar remains of famed 1987 supernova found at last

By -
https://www.science.org/content/article/stellar-remains-famed-1987-supernova-found-last By DANIEL CLERY , Science.  Excerpt: When a nearby star exploded in 1987, it created the first supernova visible to the naked eye in 4 centuries and became one of the most intensely studied objects in space. Now, after more than 35 years of searching, researchers have finally discovered the cinder left behind. Using NASA’s new giant space telescope JWST, astronomers spotted  glowing gas at the center of the blast that can only have been energized by something hot and compact inside it , they report this week in Science. They believe a neutron star, all that remains of the shattered star, is responsible.... 
Read more

Planets around dead stars offer glimpse of the Solar System’s future—after the Sun swallows us up

By -
https://www.science.org/content/article/planets-around-dead-stars-offer-glimpse-solar-system-s-future-after-sun-swallows-us By JONATHAN O’CALLAGHAN , Science.  Excerpt: In about 5 billion years the Sun will balloon up into a red giant, consuming Mercury, probably Venus, and maybe even Earth. But even if the outer planets avoid being swallowed up, they might eventually get pulled in or ejected from the Solar System. A new discovery suggests they can survive intact. Using NASA’s JWST space telescope, astronomers have for the first time directly imaged planets on Solar System–like orbits around white dwarfs, the dead stars left after Sun-like stars swell into red giants and subside. The planets follow orbits resembling those of the giant planets in the outer Solar System—big enough for them to have escaped the inferno.... For GSS A Changing Cosmos chapter 1.
Read more

The Smallest Moon of Mars May Not Be What It Seemed

By -
https://www.nytimes.com/2023/04/25/science/mars-deimos-moon-photos.html By Jonathan O’Callaghan , The New York Times.  Excerpt: Deimos, the smaller of the two moons of Mars, might be a chip off the old block — quite literally. That’s the conclusion drawn by scientists in the United Arab Emirates, whose Hope orbiter — also called the Emirates Mars Mission and the country’s first interplanetary spacecraft — just snapped the best views of Deimos ever taken by human spacecraft. ... Mars has two irregularly shaped moons , and neither is mighty. Phobos, the larger of the two, is about 17 miles in diameter at its widest, and orbits closer to the red planet at an altitude of about 3,700 miles. Deimos is just nine miles across on its longest side, and completes an orbit of Mars every 30 hours at an altitude of 15,000 miles. The moons’ small size and quirky dimensions led to suggestions that they may be asteroids captured by Mars long ago. Not so, say researchers analyzing data recorded by Hope,
Read more