Baby Stars Discharge “Sneezes” of Gas and Dust

The baby star at the center surrounded by a bright disk called a protostellar disk. Spikes of magnetic flux, gas, and dust in blue. Researchers found that the protostellar disk will expel magnetic flux, gas, and dust—much like a sneeze—during a star's formation.

I’m really not sure what to call it but a ‘dusty sneeze’ is probably as good as anything. We have known for some years that stars surround themselves with a disk of gas and dust known as the protostellar disk. The star interacts with it, occasionally discharging gas and dust regularly. Studying the magnetic fields revealed that they are weaker than expected. A new proposal suggests that the discharge mechanism ‘sneezes’ some of the magnetic flux out into space. Using ALMA, the team are hoping to understand the discharges and how they influence stellar formation. 

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In a Distant Solar System, the JWST Sees the End of Planet Formation

This artist's illustration shows what gas leaving a planet-forming disk might look like around the T Tauri star T. Cha. Image Credit: ESO/M. Kornmesser CC BY

Every time a star forms, it represents an explosion of possibilities. Not for the star itself; its fate is governed by its mass. The possibilities it signifies are in the planets that form around it. Will some be rocky? Will they be in the habitable zone? Will there be life on any of the planets one day?

There’s a point in every solar system’s development when it can no longer form planets. No more planets can form because there’s no more gas and dust available, and the expanding planetary possibilities are truncated. But the total mass of a solar system’s planets never adds up to the total mass of gas and dust available around the young star.

What happens to the mass, and why can’t more planets form?

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One in Twelve Stars Ate a Planet

When a star eats a planet, it changes the star's metallicity. New research based on co-natal stars shows that one in twelve stars have eaten at least one planet. Image Credit: International Gemini Observatory/NOIRLab/NSF/AURA/M. Garlick/M. Zamani

That stars can eat planets is axiomatic. If a small enough planet gets too close to a large enough star, the planet loses. Its fate is sealed.

New research examines how many stars eat planets. Their conclusion? One in twelve stars has consumed at least one planet.

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Webb Sees a System That Just Finished Forming its Planets

An artistic impression adapted to highlight gas dispersing from a planet-forming disk. Credit: ESO/M. Kornmesser

Nearly 5 billion years ago a region of gas gravitationally collapsed within a vast molecular cloud. At the center of the region, the Sun began to form, while around it formed a protoplanetary disk of gas and dust out of which Earth and the other planets of the solar system would form. We know this is how the solar system began because we have observed this process in systems throughout the galaxy. But there are details of the process we still don’t understand, such as why gas planets are relatively rare in our system.

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This Planet-Forming Disk has More Water Than Earth’s Oceans

Astronomers have found water vapour in a disc around a young star exactly where planets may be forming. In this image, the new observations from the Atacama Large Millimeter/submillimeter Array (ALMA) show the water vapour in shades of blue. Image Credit: ALMA (ESO/NAOJ/NRAO)/S. Facchini et al.

Astronomers have detected a large amount of water vapour in the protoplanetary disk around a young star. There’s at least three times as much water among the dust as there is in all of Earth’s oceans combined. And it’s not spread throughout the disk; it’s concentrated in the inner disk region.

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How We Get Planets from Clumping Dust

This artist’s impression shows a young star surrounded by a protoplanetary disk, where dust grains gather together to form planetesimals—the building blocks of new planets. © ESO/L. Calçada

Our gleaming Earth, brimming with liquid water and swarming with life, began as all rocky planets do: dust. Somehow, mere dust can become a life-bearing planet given enough time and the right circumstances. But there are unanswered questions about how dust forms any rocky planet, let alone one that supports life.

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Seeing the Moment Planets Start to Form

ALMA captured this high-resolution image of the protoplanetary disk surrounding DG Taurus at a 1.3 mm wavelength. The young star is still embedded in its disk, and the smooth appearance, absent of ring-like structures, indicates a phase shortly before planets form. Credit: ALMA (ESO/NAOJ/NRAO), S. Ohashi, et al.

Nature makes few duplicates, and planets are as distinct from one another as snowflakes are. But planets all start out in the same circumstances: the whirling disks of material surrounding young stars. ALMA’s made great progress imaging these disks and the telltale gaps excavated by young, still-forming planets.

But new images from ALMA (Atacama Large Millimeter/submillimeter Array) show a star and disk so young that there are no telltale gaps in the disk. Is this the moment that planets start to form?

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Clumps Around a Young Star Could Eventually Turn Into Planets Like Jupiter

The young star V960 Mon and its surrounding dusty material, seen by SPHERE (left) and ALMA (right). Credit: ESO/ALMA (ESO/NAOJ/NRAO)/Weber et al

From the dust, we rise. Vortices within the disks of young stars bring forth planets that coalesce into worlds. At least that’s our understanding of planetary evolution, and new images from the Atacama Large Millimeter/submillimeter Array (ALMA) and the Very Large Telescope’s Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) further support this.

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Astronomers Directly Image Debris Disk and find a Jupiter-Sized Planet Orbiting a Sunlike Star

Astronomers with the SHINE collabortion observed a debris disk containing a Super-Jupiter around a young star. Credit: ALMA (ESO/NAOJ/NRAO); M. Weiss (NRAO/AUI/NSF)

According to the most widely-accepted theory, planetary systems form from large clouds of dust and gas that form disks around young stars. Over time, these disks accrete to create planets of varying size, composition, and distance from their parent star. In the past few decades, observations in the mid- and far-infrared wavelengths have led to the discovery of debris disks around young stars (less than 100 million years old). This has allowed astronomers to study planetary systems in their early history, providing new insight into how systems form and evolve.

This includes the SpHere INfrared survey for Exoplanets (SHINE) consortium, an international team of astronomers dedicated to studying star systems in formation. Using the ESO’s Very Large Telescope (VLT), the SHINE collaboration recently directly imaged and characterized the debris disk of a nearby star (HD 114082) in visible and infrared wavelengths. Combined with data from NASA’s Transiting Exoplanet Space Satellite (TESS), they were able to detect a gas giant many times the size of Jupiter (a “Super-Jupiter”) embedded within the disk.

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Ceres Probably Formed Farther out in the Solar System and Migrated Inward

This image of Ceres was taken by NASA's Dawn spacecraft on May 7, 2015, from a distance of 8,400 miles (13,600 kilometers). Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

When Sicilian astronomer Giuseppe Piazzi spotted Ceres in 1801, he thought it was a planet. Astronomers didn’t know about asteroids at that time. Now we know there’s an enormous quantity of them, primarily residing in the main asteroid belt between Mars and Jupiter.

Ceres is about 1,000 km in diameter and accounts for a third of the mass in the main asteroid belt. It dwarfs most of the other bodies in the belt. Now we know that it’s a planet—albeit a dwarf one—even though its neighbours are mostly asteroids.

But what’s a dwarf planet doing in the asteroid belt?

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