#planetary formation

[deep-space-netwerk]

please please please PLEASE share more on your Thoughts about gas giants!! i'd love to learn in a way that doesnt leave me baffled and half my brain leaking from my ears! you explained things so well in the psyche post and also i think things are generally more fun to learn from someone who is Excited To Share than from Published Research Papers where everything has been dried out For Professional Reasons- understandably so, mind, but i am not In The Field and dont know the terms lol

Okay it's taken me forever to get back to this but I AM SO GLAD YOU ASKED.

Like other planets, it all starts with a disk made of gas and dust orbiting an infant star, called a protoplanetary disk. Like these in the Orion Nebula, discovered by the Hubble!

To form terrestrial planets (rocky planets with relatively thin atmospheres like Mercury, Venus, Earth, and Mars), the gas in the protoplanetary disk coalesces to form hundreds and hundreds of rocky bodies called planetesimals, about a kilometer across. These planetesimals collide, and form dozens of protoplanets about the size of the moon. The protoplanets then collide as well, and stabilize to form the solar system as we know it today.

But, in the case of gas giants, colliding protoplanets don't form fully-finished planets. Instead, they form a core, or a seed.

We think the only thing that determines whether a planet will be terrestrial or a gas giant is simply how far away from the sun it forms - that's it. As a new sun warms its evolving solar system, it heats up the material in the protoplanetary disk. Close to the sun, the disk gets hotter, and things like water and other ices melt and evaporate into gas, making them difficult for the protoplanets to gravitationally capture. However, further away, the icy compounds stay cold enough to remain solid and coalesce along with rocky particles.

That boundary in the solar system - where ices evaporate to gas on the sunward side, and remain solid on the other - is called the "Frost Line". In our solar system, the Frost Line is right between Mars and Jupiter.

The protoplanets that form past the Frost Line turn into gas giant seeds, and are able to (kinda literally) snowball, picking up both rocky and icy material. With all that solid ice available, they grow far larger and far faster than planets in the inner solar system, and their gravity gets stronger and stronger. More gravity causes them to collect even MORE material until they're heavy enough to capture extremely lightweight elements like hydrogen and helium. Which, of course, makes them get even bigger and even heavier! Runaway growth!

But weirdly, as we study more exoplanets (planets that orbit stars other than our sun), we keep finding these huge gas giants incredibly close to their stars! Like, even closer than Mercury is to ours, which is insane. These "Hot Jupiters" break so many rules - gas giants "should" only be able to form where ice stays frozen, but here they are up close and personal with their stars, like this artist's concept!

It's possible that these planets are in the process of migrating closer to their stars, and we're managing to see them before they evaporate, but we just! Keep! Finding them!

One of my favorite parts of planetary science is how much we still have to learn. We'll think we have a pretty good idea of how things work out there, and then suddenly we'll find something that we can't explain. And there's an entire universe of weird shit - we've barely begun to scratch the surface!

[spacetimewithstuartgary]

How do rocky planets really form? A new theory for how rocky planets form could explain the origin of so-called "super-Earths"—a class of exoplanets a few times more massive than the Earth that are the most abundant type of planet in the galaxy. Further, it could explain why super-Earths within a single planetary system often wind up looking strangely similar in size, as though each system were only capable of producing a single kind of planet. "As our observations of exoplanets have grown over the past decade, it has become clear that the standard theory of planet formation needs to be revised, starting with the fundamentals. We need a theory that can simultaneously explain the formation of the terrestrial planets in our solar system as well as the origins of self-similar systems of super-Earths, many of which appear rocky in composition," says Caltech professor of planetary science Konstantin Batygin (MS '10, PhD '12), who collaborated with Alessandro Morbidelli of the Observatoire de la Côte d'Azur in France on the new theory. A paper explaining their work was published by Nature Astronomy on Jan. 12. Planetary systems begin their lifecycles as large spinning disks of gas and dust that consolidate over the course of a few million years or so. Most of the gas accretes into the star at the center of the system, while solid material slowly coalesces into asteroids, comets, planets, and moons. In our solar system, there are two distinct types of planets: the smaller rocky inner planets closest to the sun and the outer larger water- and hydrogen-rich gas giants that are farther from the sun. In an earlier study published in Nature Astronomy at the end of 2021, this dichotomy led Morbidelli, Batygin, and colleagues to suggest that planet formation in our solar system occurred in two distinct rings in the protoplanetary disk: an inner one where the small rocky planets formed and an outer one for the more massive icy planets (two of which—Jupiter and Saturn—later grew into gas giants). Super-Earths, as the name suggests, are more massive than the Earth. Some even have hydrogen atmospheres, which makes them appear almost gas giant-like. Moreover, they are often found orbiting close to their stars, suggesting that they migrated to their current location from more distant orbits. "A few years ago we built a model where super-Earths formed in the icy part of the protoplanetary disk and migrated all the way to the inner edge of the disk, near the star," says Morbidelli. "The model could explain the masses and orbits of super-Earths but predicted that all are water-rich. Recent observations, however, have demonstrated that most super-Earths are rocky, like the Earth, even if surrounded by a hydrogen atmosphere. That was the death sentence for our old model." Over the past five years, the story has gotten even weirder as scientists—including a team led by Andrew Howard, professor of astronomy at Caltech; Lauren Weiss, assistant professor at the University of Notre Dame; and Erik Petigura, formerly a Sagan Postdoctoral Scholar in Astronomy at Caltech and now a professor at UCLA—have studied these exoplanets and made an unusual discovery: while there exists a wide variety of types of super-Earths, all of the super-Earths within a single planetary system tend to be similar in terms of orbital spacing, size, mass, and other key features. "Lauren discovered that, within a single planetary system, super-Earths are like 'peas in a pod,'" says Howard, who was not directly connected with the Batygin–Morbidelli paper but has reviewed it. "You basically have a planet factory that only knows how to make planets of one mass, and it just squirts them out one after the other." So, what single process could have given rise to the rocky planets in our solar system but also to uniform systems of rocky super-Earths? "The answer turns out to be related to something we figured out in 2020 but didn't realize applied to planetary formation more broadly," Batygin says. In 2020, Batygin and Morbidelli proposed a new theory for the formation of Jupiter's four largest moons (Io, Europa, Ganymede, and Callisto). In essence, they demonstrated that, for a specific size range of dust grains, the force dragging the grains toward Jupiter and the force (or entrainment) carrying those grains in an outward flow of gas cancel each other perfectly. That balance in forces created a ring of material that constituted the solid building blocks for the subsequent formation of the moons. Further, the theory suggests that bodies would grow in the ring until they become large enough to exit the ring due to gas-driven migration. After that, they stop growing, which explains why the process produces bodies of similar sizes. In their new paper, Batygin and Morbidelli suggest that the mechanism for forming planets around stars is largely the same. In the planetary case, the large-scale concentration of solid rocky material occurs at a narrow band in the disk called the silicate sublimation line -- a region where silicate vapors condense to form solid, rocky pebbles. "If you're a dust grain, you feel considerable headwind in the disk because the gas is orbiting a bit more slowly, and you spiral toward the star; but if you're in vapor form, you simply spiral outward, together with the gas in the expanding disk. So that place where you turn from vapor into solids is where material accumulates," Batygin says. The new theory identifies this band as the likely site for a "planet factory" that, over time, can produce several similarly sized rocky planets. Moreover, as planets grow sufficiently massive, their interactions with the disk will tend to draw these worlds inward, closer to the star. Batygin and Morbidelli's theory is backed up by extensive computer modeling but began with a simple question. "We looked at the existing model of planet formation, knowing that it does not reproduce what we see, and asked, 'What assertion are we taking for granted?'" Batygin says. "The trick is to look at something that everybody takes to be true but for no good reason." In this case, the assumption was that solid material is dispersed throughout the protoplanetary disks. By jettisoning that assumption and instead supposing that the first solid bodies form in rings, the new theory can explain different types of planetary systems with a unified framework, Batygin says. If the rocky ring contains a lot of mass, planets grow until they migrate away from the ring, resulting in a system of similar super-Earths. If the ring contains little mass, it produces a system that looks much more like our solar system's terrestrial planets. "I'm an observer and an instrument builder, but I pay extremely close attention to the literature," Howard says. "We get a regular dribble of little-but-still-important contributions. But every five years or so, someone comes out with something that creates a seismic shift in the field. This is one of those papers." The paper is titled "Formation of Rocky Super-Earths From A Narrow Ring of Planetesimals." Funding to support this research came from Caltech, Observatoire de la Côte d’Azur, the David and Lucile Packard Foundation, the National Science Foundation, and the European Research Council. IMAGE....Artist's rendering of a protoplanetary disk with planets forming. CREDIT Caltech

[jingszo]

Scientists have discovered a rare sight in a nearby star system: Six planets orbiting their central star in a rhythmic beat. The planets move in an orbital waltz that repeats itself so precisely it can be readily set to music.

This discovery is going to become a benchmark system to study how sub-Neptunes, the most common type of planets outside of the solar system, form, evolve, what are they made of, and if they possess the right conditions to support the existence of liquid water in their surfaces.

A rare resonance

The six planets orbit a star known as HD110067, which lies around 100 light-years away in the northern constellation of Coma Berenices.

[headlinehorizon]

Red Dwarf Reveals Unexpected Planet: Headline Horizon!

In the latest news, astronomers have made a surprising discovery - a planet much larger than expected orbiting a red dwarf star. This revelation challenges previous theories on planetary formation around these common stars.

[ianmiller42]

The Martian Core Has Shrunk

Back in 2021 (Nature, 591, 514-515) it was announced that the Insight lander on Mars, which had a seismometer, had detected vibrations through the planet that showed it had a surprisingly large core, specifically with a radius of about 1830 km. Putting this in context, the Earth nominally has two cores: the radius of Earth’s inner core is about 1220 km, while the outer core adds a further 2260…

[thecontentlibrary32]

Unveiling the Distinction: Exploring the Differences Between Planets and Stars

Celestial bodies of varied shapes, sizes, and properties are dispersed over the great cosmic expanse, capturing our wonder and imagination. Planets and stars are prominent among these cosmic wonders, each with special characteristics and significance. Join us on an educational adventure as we explore the differences between planets and stars, revealing their distinguishing characteristics and…

[mindblowingscience]

Clouds of dust and gas not far from our solar system are giving astronomers a rare glimpse into the earliest stages of planet formation. These clouds, which are between 200,000 and 500,000 years old and lie within 700 light-years of Earth, have been spotted hosting dusty, gas-rich disks around a central star — the birthplaces of planets. Photos of these features, captured by the Atacama Large Millimeter/submillimeter Array (ALMA), were unveiled on Monday (Jan. 8) at the American Astronomical Society conference being held in New Orleans and online.

Continue Reading.

[sabakos]

I think anyone trying to derive the metallic composition of the crust of other planets from "first principles" is probably firmly atop Mount Stupid.

[iceslushii]

my chemical romance. send post

[spacenutspod]

The Space, Astronomy & Science Podcast. SpaceTime Series 27 Episode 38 *Witnessing the Final Stages of Planetary Formation For the first time, astronomers have captured the end of the planetary formation process, observing the dispersal of gas from a young star's circumstellar disk. The James Webb Space Telescope has provided unprecedented images of the Tchar star system, where a vast gap in its disk suggests we're witnessing the final act in its planetary evolution. The study sheds light on the fate of gas giants and terrestrial planets, revealing the delicate dance of creation that shapes nascent solar systems. *The Devil's Comet: A Green Spectacle in the Sky Comet 12P/Pons-Brooks, with its distinctive green hue and horned appearance, is making its first visit to the inner solar system in over 70 years. This Mount Everest-sized icy wanderer could grace our skies with its naked-eye visibility as it reaches perihelion this April. Nicknamed the 'Devil's Comet', its cryovolcanic nature promises a celestial show that won't return until 2095. *The Dust that Doomed Dinosaurs A new study proposes that fine dust particles from the Chicxulub asteroid impact contributed significantly to the mass extinction event that ended the reign of the non-avian dinosaurs. By blocking photosynthesis and plunging the Earth into a cold, dark winter, this fine dust may have been the final nail in the coffin for many species, reshaping life on our planet forever. For more SpaceTime and to support the show, visit our website at https://spacetimewithstuartgary.com where you can access our universal listen link, find show notes, and learn how to become a patron. Listen to SpaceTime on your favorite podcast app with our universal listen link: https://spacetimewithstuartgary.com/listen and access show links via https://linktr.ee/biteszHQ Support the show: https://www.spreaker.com/podcast/spacetime-with-stuart-gary--2458531/support For more space and astronomy podcasts, visit our HQ at https://bitesz.com

[bbygirl-obi]

"the jedi don't have therapists-"

jedi philosophy, and in particular the practices and teachings that jedi were expected to implement in their everyday lives, was therapy. dialectical behavior therapy (dbt), to be exact. anyone who's familiar with dbt knows where i'm already going with this, but like genuinely look up the basic tenets of dbt and it's identical with what the jedi were doing.

dbt, to put it simply, is a specific therapy technique that was designed for ptsd and past trauma. it's pretty different from traditional talk therapy. it combines a few different environments (individual, group, etc.), recognizing that no single format of treatment can stand alone.

the key focuses of dbt include:

emotional regulation- understanding, being more aware of, and having more control over your emotions

mindfulness- regulating attention and avoiding anxious fixation on the past or future

interpersonal effectiveness- navigating interpersonal situations

distress tolerance- tolerating distress and crises without spiraling and catastrophizing

i'm sure it's already clear from that list alone how much the jedi teachings correspond with the goals of dbt. the jedi value, teach, and practice the following:

identifying and understanding emotions

mindfulness and living in the present

compassion, diplomacy, and conflict resolution (on interpersonal scales, not just planetary or galactic)

accepting and tolerating certain levels of distress or discomfort (particularly mental, such as discomfort at the thought of losing a loved one to death)

idk man seems almost as if jedi mental health practices and dbt are two sides of a completely identical coin. (fun fact: both star wars and dbt are products of the 70s.)

and guess what? dbt was specifically designed as a treatment for borderline personality disorder. remember that one? or, if you don't, maybe you remember a specific character, the one who was literally used as an example by my professor in my undergrad psych class when she was teaching us about bpd?

tldr: simply existing within the jedi community, practicing jedi teachings, surrounded by a support network of other jedi of all life stages, was the therapy for anakin. even when viewed through a modern lens. it was even, more specifically, the precise type of therapy that has developed in modern times to treat the exact types of mental issues he was struggling with.

[spacetimewithstuartgary]

Shift to ultraviolet-driven chemistry in planet-forming disks marks beginning of late-stage planet formation The chemistry of planet formation has fascinated researchers for decades because the chemical reservoir in protoplanetary discs—the dust and gas from which planets form—directly impacts planet composition and potential for life. New research from the University of Michigan Department of Astronomy suggests that chemistry in late-stage planet development is fueled by ultraviolet rays, rather than cosmic rays or X-rays, and this new understanding provides a chemical signature that helps researchers trace exoplanets back to their cosmic nurseries in the planet-forming disks. Jenny Calahan, a doctoral student in astronomy and first author of the paper, which appears in Nature Astronomy, said the discovery was part happy accident, part building on previous work. "It has been shown that there are bright, complex organic molecules present in the coldest and densest parts of planet-forming disks," Calahan said. "This bright emission has been puzzling because we expect these molecules to be frozen out at these temperatures, not in the gas where we can observe them." These molecules are emitting from regions that are minus-400 degrees Fahrenheit, and at these temperatures they're thought to be frozen onto tiny solids that astronomers label as dust grains, or for the later mm-to-cm-sized solids as pebbles. These molecules should add to an icy coating on the grains, so they cannot be observed in the gas. The planet-forming disk has three main components, a pebble-rich dusty midplane, a gas atmosphere and a small dust population coupled to the gas. As the planet-forming disk evolves over time, the changing environment affects the chemistry within. To account for the observed brightness, Calahan adjusted her model to decrease the mass of the small dust population—which typically blocks UV photons––to allow more UV photons to penetrate deep into these coldest regions of the disc. This reproduced the observed brightness. "If we have a carbon-rich environment paired with a UV-rich environment due to the evolution of the small solids in planet forming regions, we can produce complex organics in the gas and reproduce these observations," she said. This represents the evolution of small dust over time. About 20 years ago, researchers realized that the chemistry of the gaseous disk is governed by chemistry operating on shorter timescales and powered by sources such as cosmic rays and X-rays, said Edwin Bergin, principal investigator, professor and chair of astronomy. "Our new work suggests that what really matters is the ultraviolet radiation field generated by the star accreting matter from the disk," he said. "The initial steps in making planets, forming larger and larger solids, shifts the chemistry from cosmic rays and X-ray-driven early, to UV-driven during the phase where giant planets are thought to be born. "Jenny's work tells us for terrestrial worlds, if you wonder how they get things like water, the key part of the evolution is the early phases before this shift occurs. That is when the volatile molecules that comprise life––carbon, hydrogen, nitrogen––are implanted in solids that make Earth-like worlds. These planets are not born in this phase but rather the composition of solids becomes fixed. The later stages of this model tells us how to determine the composition of material that makes giant planets." Co-authors include: Arthur Bosman and Evan Rich, both of the U-M Department of Astronomy.

[ianmiller42]

Where is Life to be Found?

One question that keeps bedevilling us is, how many planets in the galaxy are habitable, and could sustain technological life? I am going to limit it to rocky planets. A water world may well have life, although there would be difficulties getting started, but it most certainly will not develop technology. Animals that swim are evolutionarily constrained to have fins rather than hands, and you…

[fandom]

Space! ft. NASA

It was a big year in our part of the cosmos. We’ve invited our friends at @nasa​ to recap all the stunning scientific advances that gave us a deeper glimpse into the galaxy around us this year.

JWST Showed Us Space with New Eyes

In July 2022, we saw the first full-color images and data from the largest and most powerful space observatory ever made: the James Webb Space Telescope. This landscape of “mountains” and “valleys” is speckled with glittering stars, and called the Cosmic Cliffs. It’s the edge of the star-birthing Carina Nebula. Usually, the early phases of star formation are difficult to capture, but the infrared Webb can peer through cosmic dust thanks to its extreme sensitivity, spatial resolution, and imaging capability.

Credit: NASA, ESA, CSA, and STScI 

Artemis I Flew Us Beyond the Moon 

NASA’s most powerful rocket, the Space Launch System (SLS), lifted off for the first time on November 16, 2022, launching the Orion spacecraft on a journey around the Moon. Orion has now traveled farther from Earth than any other spacecraft designed to carry humans to deep space and safely return them to Earth. The Artemis I mission is the first part of a new era of deep space exploration. The program is designed to take astronauts back to the Moon and eventually on to Mars.

Credit: NASA

This One’s for the Dinosaurs

NASA’s DART mission successfully redirected an asteroid—the first time humanity has ever changed the orbit of a celestial object in space. On Sept. 26, 2022, the vending-machine-size spacecraft slammed into the stadium-size asteroid Dimorphos, slightly shortening its orbit around its much larger companion asteroid Didymos. Neither asteroid posed a threat to Earth before or after the test. The objective was to test this “planetary defense” technique, should an asteroid ever pose a threat. Note: there are no known asteroid threats to Earth for at least the next 100 years, but NASA is keeping an eye on the skies, just in case.

Credit: NASA/JHUAPL

Be sure to follow @nasa​ for more!

[apod]

2024 January 7

The Cat's Eye Nebula in Optical and X-ray Image Credit: NASA, ESA, Hubble Legacy Archive; Chandra X-ray Obs.; Processing & Copyright: Rudy Pohl

Explanation: To some it looks like a cat's eye. To others, perhaps like a giant cosmic conch shell. It is actually one of the brightest and most highly detailed planetary nebula known, composed of gas expelled in the brief yet glorious phase near the end of life of a Sun-like star. This nebula's dying central star may have produced the outer circular concentric shells by shrugging off outer layers in a series of regular convulsions. The formation of the beautiful, complex-yet-symmetric inner structures, however, is not well understood. The featured image is a composite of a digitally sharpened Hubble Space Telescope image with X-ray light captured by the orbiting Chandra Observatory. The exquisite floating space statue spans over half a light-year across. Of course, gazing into this Cat's Eye, humanity may well be seeing the fate of our sun, destined to enter its own planetary nebula phase of evolution ... in about 5 billion years.

∞ Source: apod.nasa.gov/apod/ap240107.html