Contrary to previous thought, a giant planet in a wild orbit doesn’t mean there can’t be an Earth-like planet in the same system. What's more, the view from that Earth-like world as its giant neighbor moves past would be unlike anything we’ve ever seen.
Artist’s concept of Venus – brightest planet visible from Earth and a dazzling light low in the west after sunset now – in contrast to the brightness of the giant planet in the distant star system HR 5183. Image via UC Riverside .
HR 5183b is an exoplanet – discovered earlier this year – orbiting a distant sun some 103 light-years away in the direction of our constellation Virgo the Maiden. The planet has at least three times the mass of Jupiter, our solar system’s most massive and biggest world. Even more interestingly, the giant exoplanet HR 5183b has a highly eccentric orbit. If its orbit were placed within our solar system, this huge world would travel closer to the sun than Jupiter, then swing outward again beyond the orbit of Neptune. Its wild orbit gave it the nickname of the whiplash planet . Shortly after its discovery, astronomers said such a large planet in such an orbit precluded the presence of an Earth-like planet in the same solar system.
Not to change the topic here:
It Seems Impossible, But Somehow This Planet Survived its Star's Red Giant Phase - Universe
Astronomers working with TESS (Transiting Exoplanet Survey Satellite) data have found a planet where it shouldn't be: in the space recently filled by its host star when it was a red giant.
TESS uses Asteroseismology to examine stars. It measures the tiny oscillations in a star that gives clues to its interior structure. These clues are hidden from other types of observations, like brightness and surface temperature. In a new published study, the authors examined two red-giant stars: HD 212771 and HD 203949. These are the first asteroseismology studies of stars that are known to host planets.
The title of the paper is " TESS Asteroseismology of the known red-giant host stars HD 212771 and 203949 ." The lead author of the paper is Tiago Campante, from the University of Porto, Portugal. In a press release , Campante explained how TESS's power helped the authors study these stars: "TESS observations are precise enough to allow measuring the gentle pulsations at the surfaces of stars. These two fairly evolved stars also host planets, providing the ideal test-bed for studies of the evolution of planetary systems."
NASA Just Picked New Planetary Missions to Study. Here Are The Most Exciting Ones
Look, Mars is great. It's full of great rocks , and those blue sunsets are just top-notch. But there's no denying it: Mars definitely gets way more attention than other planets. At time of writing, there are eight active probes on or orbiting Mars.
Other Solar System planets have their secrets too, and NASA has just funded a bunch of planetary mission concept studies to see what's feasible to explore in the near future.
These studies will be published in the 2023 Planetary Science Decadal Survey, a US National Research Council publication produced every 10 years or so, identifying key issues and outlining recommendations for the coming decade in planetary science.
Not all of the concept studies will be selected to be developed into full missions; and then, not all the selected missions will end up being fully developed. A Mars mission concept from the 2013 survey, for instance, was cancelled .
Wind Erosion On Mars And Other Small Terrestrial Planets - Astrobiology
We carried out wind tunnel experiments on parabolic flights with 100 μm Mojave Mars simulant sand. The experiments result in shear stress thresholds and erosion rates for varying g-levels at 600 Pa pressure.
Our data confirm former results on JSC Mars 1A simulant where the threshold shear stress is lower under Martian gravity than extrapolated from earlier ground-based studies which fits observations of Martian sand activity. The data are consistent with a model by Shao and Lu (2000) and can also be applied to other small terrestrial (exo)-planets with low pressure atmospheres.
Maximilian Kruss, Grzegorz Musiolik, Tunahan Demirci, Gerhard Wurm, Jens Teiser
(Submitted on 5 Nov 2019)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Journal reference: Icarus 337 (2020), 113438
DOI: 10.1016/j.icarus.2019.113438
Cite as: arXiv:1911.01692 [astro-ph.EP] (or arXiv:1911.01692v1 [astro-ph.EP] for this version)
Submission history
From: Maximilian Kruss
[v1] Tue, 5 Nov 2019 10:02:03 UTC (750 KB)
https://arxiv.org/abs/1911.01692
Astrobiology, Astrogeology
And here's another article:
Lessons from scorching hot weirdo-planets
Illustration of a hot Jupiter planet in the Messier 67 star cluster. Hot Jupiters are so named because of their close proximity — usually just a few million miles — to their star, which drives up temperatures and can puff out the planets.
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Hot Jupiters were the first kind of exoplanet found. A quarter-century later, they still perplex and captivate — and their origins hold lessons about planet formation in general.
In 1995, after years of effort, astronomers made an announcement: They'd found the first planet circling a sun-like star outside our solar system. But that planet, 51 Pegasi b, was in a quite unexpected place — it appeared to be just around 4.8 million miles away from its home star and able to dash around the star in just over four Earth-days. Our innermost planet, Mercury, by comparison, is 28.6 million miles away from the sun at its closest approach and orbits it every 88 days.
Spot six planets in the sky this week: Mercury, Mars, Uranus and more | New Scientist
THE coming week is a great time to look for planets. A new moon on 28 October means no moonlight and, with the exception of Neptune , every planet is visible at some point in the coming days. Even distant Uranus, which at 8 pm GMT on 27 October will be a mere 2.8 billion kilometres away.
Venus is the easiest to find, with an apparent magnitude of -4.6. In the magnitude scale, objects with lower numbers are brighter. It is close to the sun, …
'We've found dozens of potentially habitable planets - now we need to study them in detail' |
In 2017, his SPECULOOS project discovered seven Earth-sized planets around the TRAPPIST-1 system, one of the most intriguing planetary systems found so far – and now the hunt is on for more weird, wonderful, and even Earth-like worlds.
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'The SPECULOOS project aimed to develop facilities composed of several robotic telescopes to search for exoplanets – planets orbiting around other stars – that transit very nearby (Earth) and around very tiny small stars (ultra-cool dwarfs), basically, the least massive kind of star. The goal was to search for planets that are potentially habitable and that are well-suited for detailed (atmospheric) characterisation by (NASA's) upcoming James Webb Space Telescope (due to launch in 2021). Now we really want to move from exoplanet detection to exoplanet detailed study characterisation.
'In 2017, (the project) achieved a wonderful result because it detected the famous TRAPPIST-1 system , which is composed of seven Earth-sized planets around one of the brightest and nearest SPECULOOS targets. This system is the best system so far for the study of temperate, potentially habitable planets with James Webb.'
'Dirty' Collisions Shed Light on Planet Formation | Space
Planetary models are incredibly complex, requiring scientists to account for everything that happens to a growing planet on timescales spanning a few days to millions of years. In the past, astronomers would simplify their models of colliding objects by assuming that all of the material from both the impactor and its target perfectly merged into a single object — an unrealistic expectation, since at least some pieces would most likely be flung into space and lost. But because computers of the past were less powerful than those today, scientists were forced into the simplification.
In the past decade, however, improvements in computational power have allowed researchers to begin studying more-realistic collision scenarios. Now, scientists can model so-called hit-and-run collisions , where two bodies scraped each other in passing, or even the total annihilation that could occur when two planetary embryos slammed together. These imperfect "dirty collisions" not only affect how large planets grow to be but also help to explain their orbits.
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