planet formation Archives

October 7, 2024October 7, 2024 by Matt Williams

The JWST Reveals New Things About How Planetary Systems Form

This artist’s impression of a planet-forming disk surrounding a young star shows a swirling “pancake” of hot gas and dust from which planets form. Credit and ©: National Astronomical Observatory of Japan (NAOJ)

Every second in the Universe, more than 3,000 new stars form as clouds of dust and gas undergo gravitational collapse. Afterward, the remaining dust and gas settle into a swirling disk that feeds the star’s growth and eventually accretes to form planets – otherwise known as a protoplanetary disk. While this model, known as the Nebular Hypothesis, is the most widely accepted theory, the exact processes that give rise to stars and planetary systems are not yet fully understood. Shedding light on these processes is one of the many objectives of the James Webb Space Telescope (JWST).

In a recent study, an international team of astronomers led by University of Arizona researchers and supported by scientists from the Max Planck Institute of Astronomy (MPIA) used the JWST’s advanced infrared optics to examine protoplanetary disks around new stars. These observations provided the most detailed insights into the gas flows that sculpt and shape protoplanetary disks over time. They also confirm what scientists have theorized for a long time and offer clues about what our Solar System looked like roughly 4.6 billion years ago.

September 17, 2024September 17, 2024 by Matt Williams

Astronomers Have Found a Star with a Hot Jupiter and a Cold Super Jupiter in Orbit

Artist's vision of a cold super-Jupiter in the HD 118203 system. It is an extremely massive gas planet orbiting its star in an orbit six times that of Earth. Credit: NCU/ Maciejewski, G. et al (2024)

Located in the constellation Ursa Major, roughly 300 light-years from Earth, is the Sun-like star HD 118203 (Liesma). In 2006, astronomers detected an exoplanet (HD 118203 b) similar in size and twice as massive as Jupiter that orbits very closely to Liesma (7% of the distance between Earth and the Sun), making it a “Hot Jupiter.” In a recent study, an international team of astronomers announced the detection of a second exoplanet in this system: a Super Jupiter with a wide orbit around its star. In short, they discovered a “Cold Super-Jupiter” in the outskirts of this system.

September 8, 2024September 8, 2024 by Matt Williams

ALMA Detects Hallmark “Wiggle” of Gravitational Instability in Planet-Forming Disk

ALMA images reveal vast spiral arms in the AB Aurigae circumstellar disk (three rightmost panels), and counterparts observed with VLT/SPHERE (leftmost panel). Credit: ALMA (ESO/NAOJ/NSF NRAO), VLT/SPHERE (ESO), Speedie et al.

According to Nebula Theory, stars and their systems of planets form when a massive cloud of gas and dust (a nebula) undergoes gravitational collapse at the center, forming a new star. The remaining material from the nebula then forms a disk around the star from which planets, moons, and other bodies will eventually accrete (a protoplanetary disk). This is how Earth and the many bodies that make up the Solar System came together roughly 4.5 billion years ago, eventually settling into their current orbits (after a few migrations and collisions).

However, there is still debate regarding certain details of the planet formation process. On the one hand, there are those who subscribe to the traditional “bottom-up” model, where dust grains gradually collect into larger and larger conglomerations over tens of millions of years. Conversely, you have the “top-down” model, where circumstellar disk material in spiral arms fragments due to gravitational instability. Using the Atacama Large Millimeter/submillimeter Array (ALMA), an international team of astronomers found evidence of the “top-down” model when observing a protoplanetary disk over 500 light-years away.

March 28, 2024March 28, 2024 by Evan Gough

Webb Joins the Hunt for Protoplanets

This artist’s impression shows the formation of a gas giant planet embedded in the disk of dust and gas in the ring of dust around a young star. A University of Michigan study aimed the James Webb Space Telescope at a protoplanetary disk surrounding a protostar called SAO 206462, hoping to find a gas giant planet in the act of forming. Image credit: ESO/L. Calçada

We can’t understand what we can’t clearly see. That fact plagues scientists who study how planets form. Planet formation happens inside a thick, obscuring disk of gas and dust. But when it comes to seeing through that dust to where nascent planets begin to take shape, astronomers have a powerful new tool: the James Webb Space Telescope.

February 29, 2024February 29, 2024 by Evan Gough

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.

February 29, 2024February 29, 2024 by Evan Gough

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.

December 5, 2023December 5, 2023 by Evan Gough

This Planet is Way Too Big for its Star

This artist's illustration shows what the star LHS 3145 might look like from the surface of its planet, LHS 314b. Image Credit: Penn State / Penn State. Creative Commons

Scientists love outliers. Outliers are nature’s way of telling us what its boundaries are and where its limits lie. Rather than being upset when an outlier disrupts their understanding, scientists feed on the curiosity that outliers inspire.

It’s true in the case of a new discovery of a massive planet orbiting a small star. That goes against our understanding of how planets form, meaning our planet-formation model needs an update.

November 26, 2023November 26, 2023 by Mark Thompson

JWST Reveals Protoplanetary Disks in a Nearby Star Cluster

This composite image contains X-ray data from NASA’s Chandra X-ray Observatory and the ROSAT telescope (purple), infrared data from NASA’s Spitzer Space Telescope (orange), and optical data from the SuperCosmos Sky Survey (blue) made by the United Kingdom Infrared Telescope. Located in our galaxy about 5,500 light years from Earth, NGC 6357 is actually a “cluster of clusters,” containing at least three clusters of young stars, including many hot, massive, luminous stars. The X-rays from Chandra and ROSAT reveal hundreds of point sources, which are the young stars in NGC 6357, as well as diffuse X-ray emission from hot gas — Composite images of NGC6357 (Credit : NASA)

The Orion Nebula is a favourite among stargazers, certainly one of mine. It’s a giant stellar nebula out of which, hot young stars are forming. Telescopically to the eye it appears as a grey/green haze of wonderment but cameras reveal the true glory of these star forming regions. The Sun was once part of such an object and astronomers have been probing their secrets for decades. Now, a new paper presents the results from a detailed study from the James Webb Space Telescope (JWST) that has been exploring planet forming disks around stars in the Lobster Nebula.

October 30, 2023October 30, 2023 by Evan Gough

JWST Searches for Planets in the Fomalhaut System

This image shows Fomalhaut, the star around which the newly discovered planet orbits. Fomalhaut is much hotter than our Sun, 15 times as bright, and lies 25 light-years from Earth. It is blazing through hydrogen at such a furious rate that it will burn out in only one billion years, 10% the lifespan of our star. The field of view is 2.7 x 2.9 degrees.

The Fomalhaut system is nearby in astronomical terms, and it’s also one of the brightest stars in the night sky. That means astronomers have studied it intensely over the years. Now that we have the powerful James Webb Space Telescope the observations have intensified.

The Fomalhaut system has a confounding and complex dusty disk, including a dusty blob. The blob has been the subject of an ongoing debate in astronomy. Can the JWST see through its complexity and find answers to the systems unanswered questions?

October 10, 2023October 10, 2023 by Evan Gough

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?