"If you wish to make an apple pie truly from scratch, you must first invent the universe."

— Carl Sagan

Feed aggregator

The dome-shaped Brandburg Massif near the Atlantic coast of central Namibia

NASA - Breaking News - Mon, 09/09/2024 - 11:45am

The dome-shaped Brandburg Massif, near the Atlantic coast of central Namibia, containing Brandberg Mountain, the African nation’s highest peak and ancient rock paintings going back at least 2,000 years, is pictured from the International Space Station as it orbited 261 miles above.

Image Credit: NASA

Categories: NASA

Public Affairs Manager Gary Jordan

NASA - Breaking News - Mon, 09/09/2024 - 11:39am

“It’s 2 a.m. in the morning on a Sunday. You have your headset in your hand. You’re about to walk into Mission Control. And you understand — in the darkness, the crickets chirping, the lights shining on the building — you understand where you’re going and what you’re a part of.

“This is the building where we heard astronauts say, ‘Houston, we’ve had a problem.’ Where we heard, ‘the Eagle has landed.’ And the people on the ground supporting those historic missions were in this building — and now I get to be a part of that.

“There is just this undying sense of wonder every time I walk into this building. Not to say that there isn’t an undying sense of wonder at many of the other buildings at Johnson [Space Center]. But with this building in particular, having that ownership and that responsibility as I walk in — that will never go away. It’s wonderful.”

—Gary Jordan, Public Affairs Manager, NASA’s Johnson Space Center

Image Credit: NASA/Robert Markowitz
Interviewer: NASA/Thalia Patrinos

Check out some of our other Faces of NASA.

Categories: NASA

Iron Winds are Blowing on WASP-76 b

Universe Today - Mon, 09/09/2024 - 11:39am

Exoplanets have been discovered with a wide range of environmental conditions. WASP-76b is one of the most extreme with a dayside temperature of over 2,000 degrees. A team of researchers have found that it’s even more bizarre than first thought! It’s tidally locked to its host star so intense winds encircle the planet. They contain high quantities of iron atoms that stream from the lower to upper layers around the atmosphere.

Exoplanets exist outside of our Solar System and orbit other stars. The first confirmed discovery was back in the 1990’s and since then, over 5,200 have been discovered. Many of them are gas giants like Jupiter or Saturn and others are small rocky Earth like planets, minus perhaps their habitability status. As more advanced telescopes and detection techniques are developed not only will our detection levels increase further but so will our ability to explore these alien worlds. 

Artist impression of glory on exoplanet WASP-76b. Credit: ESA

One such exoplanet, WASP-76b has received quite a lot of attention of late. It is an ultra-hot gas giant that is 640 light years from us in the direction of the constellation Pisces. It was discovered back in 2013 and has an orbit that is very close to its host star, completing one orbit in just 1.8 Earth days! It’s the proximity to the star that has led to the extreme daytime temperatures of over 2,000 degrees. The intense heat is thought to vaporise iron which then condenses into liquid on the cooler night-time side and fall as iron rain! 

A team of astronomers, with some from the University of Geneva, announced their findings in the journal Astronomy & Astrophysics of evidence for intense iron winds in the atmosphere of WASP-76b. Astronomers have been focussing on this planet since its discovery to try and understand the mechanisms in the atmosphere of this ultra-hot Jupiter world. It really is a fascinating world and even a rainbow was detected there last April! 

The team kept their attention on the day-time side where the temperatures are far higher. They used the ESPRESSO spectrograph that was installed on the European Southern Observatory’s Very Large Telescope (yes that’s its name!) It is known for its stability and high spectral resolution so it can discern wonderfully fine levels of detail in a stellar spectrum. 

The four 8.2-metre Unit Telescopes of the Very Large Telescope at the Paranal Observatory complex. ESO/VLT

Using a technique known as high resolution emission spectroscopy, the team studied the visible light spectrum. The approach relies upon the detection of emission lines in a spectrum and enables the chemical composition to be decoded. Here they detected the chemical signature of iron and found that they were moving from lower levels to the higher layers of the atmosphere.

The study of exoplanet atmospheres help us to further develop our understanding of the range of environments on these alien worlds. As a gas giant, the discoveries on WASP-76b help us learn a little more about the climates of worlds that are barraged by extreme levels of radiation from their host star.

Source : Iron winds on an ultra-hot exoplanet

The post Iron Winds are Blowing on WASP-76 b appeared first on Universe Today.

Categories: Astronomy

Endangered wombat's rare encounter with echidna caught on camera

New Scientist Space - Cosmology - Mon, 09/09/2024 - 11:33am
A camera trap at an Australian nature refuge has captured a boisterous interaction between a northern hairy-nosed wombat and an echidna
Categories: Astronomy

Endangered wombat's rare encounter with echidna caught on camera

New Scientist Space - Space Headlines - Mon, 09/09/2024 - 11:33am
A camera trap at an Australian nature refuge has captured a boisterous interaction between a northern hairy-nosed wombat and an echidna
Categories: Astronomy

How AI is helping us search the universe for alien technosignatures

Space.com - Mon, 09/09/2024 - 11:15am
"It's now a part of mainstream astrophysics."
Categories: Astronomy

Celebrate International Observe the Moon Night at NASA Goddard

NASA - Breaking News - Mon, 09/09/2024 - 11:06am

2 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

The public is invited to celebrate International Observe the Moon Night on Saturday, Sept. 14, from 6 to 9 p.m. EDT at NASA Goddard’s Visitor Center in Greenbelt, Maryland.

International Observe the Moon Night is a time to come together with fellow Moon enthusiasts and curious people around the world. The public is invited to learn about lunar science and exploration, take part in celestial observations, and honor cultural and personal connections to the Moon.

Save the date! International Observe the Moon Night is September 14, 2024!NASA

During the Goddard event, attendees will be able to participate in a variety of interactive hands-on activities. There will also be a photo booth, Moon-themed presentations, and lunar and astronomical observing with telescopes. 

This free event is open to the public and will occur rain or shine.

International Observe the Moon Night occurs annually in September or October, when the Moon is around first quarter – a great phase for evening observing. Last year, almost a million people participated in 123 countries and all 7 continents. This year, NASA is celebrating 15 years of the program!

International Observe the Moon Night is sponsored by NASA’s LRO (Lunar Reconnaissance Orbiter) mission and the Solar System Exploration Division of NASA’s Goddard Space Flight Center, with support from many partners. LRO is managed by Goddard for the Science Mission Directorate at NASA Headquarters in Washington.

No registration is needed.

To participate in International Observe the Moon Night from wherever you may be, tune into our NASA broadcast or watch live streams of the Moon from telescopes around the world on our Live Streams page on Sept. 14: https://moon.nasa.gov/observe-the-moon-night/participate/live-streams/.

For directions to the Goddard Visitor Center, go to:

https://www.nasa.gov/centers/goddard/visitor/directions/index.html

To learn more about the program, visit:

https://moon.nasa.gov/observe-the-moon-night

For more information about LRO, visit:

https://science.nasa.gov/mission/lro

Share Details Last Updated Sep 09, 2024 EditorWilliam SteigerwaldContactNancy N. Jonesnancy.n.jones@nasa.govLocationGoddard Space Flight Center Related Terms Explore More 5 min read NASA’s Hubble, Chandra Find Supermassive Black Hole Duo

Like two Sumo wrestlers squaring off, the closest confirmed pair of supermassive black holes have…

Article 17 hours ago
2 min read Hubble Examines a Busy Galactic Center

This NASA/ESA Hubble Space Telescope image features the spiral galaxy IC 4709 located around 240…

Article 4 days ago
6 min read NASA’s Hubble, MAVEN Help Solve the Mystery of Mars’ Escaping Water

Mars was once a very wet planet as is evident in its surface geological features.…

Article 5 days ago
Categories: NASA

The First Person to Receive an Eye and Face Transplant Is Recovering Well

Scientific American.com - Mon, 09/09/2024 - 11:00am

A man who received a partial face and eye transplant after a serious accident does not have any vision in the transplanted eye, but the eye itself is still alive

Categories: Astronomy

Like a Diamond in the Sky: How to Spot NASA’s Solar Sail Demo in Orbit

NASA - Breaking News - Mon, 09/09/2024 - 10:59am
NASA’s Advanced Composite Solar Sail System is seen orbiting Earth in this 13-second exposure photograph, Monday, Sept. 2, 2024, from Arlington, Virginia. The mission team confirmed the spacecraft’s unique composite boom system unfurled its reflective sail on Thursday, Aug. 29, 2024, accomplishing a critical milestone in the agency’s demonstration of next-generation solar sail technology that will allow small spacecraft to “sail on sunlight.” Just as a sailboat is powered by wind in a sail, a spacecraft can use the pressure of sunlight on a solar sail for propulsion. This technology demonstration serves as a pathfinder for future missions powered by solar sail technology.NASA/Bill Ingalls

Now that its reflective sail has deployed fully open in orbit, the Advanced Composite Solar Sail System can be seen in the night sky from many locations across the world!

Stargazers can join NASA’s #SpotTheSail campaign by using the NASA app on mobile platforms to find out when the spacecraft will be visible at their location. The app, which is free to use and available on iOS and Android, provides a location-specific schedule of upcoming sighting opportunities. A built-in augmented reality tool points users to the location of the spacecraft in real time.

Can you spot the solar sail? Share your viewing experience online using the hashtag #SpotTheSail for a chance to be featured on NASA’s website and social media channels.

Here’s how to use the sighting prediction tool: 

  • Install and open the NASA app on an iOS or Android device.
  • Tap on the “Featured” tab on the bottom navigation bar.
  • Tap on the Advanced Composite Solar Sail System mission from the Featured Missions at the top of the screen.
  • Tap on the “Sightings” tab on the bottom navigation bar. A list of all the upcoming sightings for your location will be displayed.
  • If you are using an iOS device, you can tap on the “Sky View” link for an augmented reality guide to help you locate the spacecraft’s real-time location during the visible pass.

NASA’s Advanced Composite Solar Sail System is testing new technologies in low Earth orbit, including a composite boom system that supports a four-piece sail. Not to be confused with solar panels, solar sails allow small spacecraft to “sail on sunlight,” eliminating the need for rocket fuel or other conventional propellants. This propulsion technology can enable low-cost deep space missions to increase access to space.  

For ongoing mission updates, follow us on social media:

X: @NASAAmes@NASA
Facebook: NASA AmesNASA
Instagram: @NASAAmes@NASA

NASA’s Ames Research Center in California’s Silicon Valley manages the Advanced Composite Solar Sail System project and designed and built the onboard camera diagnostic system. NASA’s Langley Research Center in Hampton, Virginia, designed and built the deployable composite booms and solar sail system. NASA’s Small Spacecraft Technology program office based at NASA Ames and led by the agency’s Space Technology Mission Directorate (STMD) in Washington, funds and manages the mission. NASA STMD’s Game Changing Development program developed the deployable composite boom technology. Rocket Lab USA, Inc of Long Beach, California, provided launch services. NanoAvionics provided the spacecraft bus.

Categories: NASA

Find Me on the Moon: NASA Lunar Navigation Challenge

NASA - Breaking News - Mon, 09/09/2024 - 10:53am
Image credit: Freelancer

NASA’s Artemis campaign is a series of lunar missions to further explore the lunar landscape to prepare for future missions to Mars. The Artemis missions will send humans to land on the moon and explore the lunar south pole. This will be NASA’s first human lunar landing since the Apollo missions over 50 years ago. The Artemis missions will be landing at the lunar south pole; this area is of interest because the permanently shadowed regions that exist there may be traps for water ice which could be accessed to support future missions to Mars. One area of interest is Shackleton Crater, measuring 13 miles (21 km) in diameter and 2.6 miles (4.2 km) deep. The crater has steep sides and continuous shadows cause the floor of the crater to be below 90 K and may have water ice trapped beneath the surface. To support these missions, NASA is seeking two solutions: one low-tech and one high-tech. While both solutions are related to navigation, they are independent challenges and solutions.

For Challenge 1, NASA is seeking an orienteering aid that will help the astronauts navigate on traverses away from the lunar lander and return back. While there were similar devices available to the Apollo astronauts, NASA is looking for new and unique solutions. Among other considerations, devices must be accurate, easy to use, able to be used on the moon’s surface by an astronaut wearing pressurized gloves. If your solution is one of the best, you could be eligible for a share of the $15,000 prize purse. 

For Challenge 2, NASA is looking for assistance in getting to and mapping the bottom of Shackleton Crater. The design must work in the extreme conditions of the lunar south pole and Shackleton Crater, map the crater, characterize and quantify what is in the crater, and send the data back to be used for future missions. If you can solve this challenge by describing your design concept in detail, you could be eligible for a share of the $30,000 prize purse.

In addition, there is $5,000 in prize money to be distributed among solutions from both challenges that show exceptional achievement.

Award: $50,000 in total prizes

Open Date: September 4, 2024

Close Date: November 25, 2024

For more information, visit: https://www.freelancer.com/contest/Find-Me-on-the-Moon-NASA-Lunar-Navigation-Challenge-2442541/details

Categories: NASA

NASA’s Hubble, Chandra Find Supermassive Black Hole Duo

NASA - Breaking News - Mon, 09/09/2024 - 10:18am
Hubble Space Telescope

  1. Home
  2. NASA’s Hubble, Chandra…
  • Missions
  •  

    5 min read

    NASA’s Hubble, Chandra Find Supermassive Black Hole Duo This is an artist’s depiction of a pair of active black holes at the heart of two merging galaxies. They are both surrounded by an accretion disk of hot gas. Some of the material is ejected along the spin axis of each black hole. Confined by powerful magnetic fields, the jets blaze across space at nearly the speed of light as devastating beams of energy. NASA, ESA, Joseph Olmsted (STScI)
    Download this artist’s depiction

    Like two Sumo wrestlers squaring off, the closest confirmed pair of supermassive black holes have been observed in tight proximity. These are located approximately 300 light-years apart and were detected using NASA’s Hubble Space Telescope and the Chandra X-ray Observatory. These black holes, buried deep within a pair of colliding galaxies, are fueled by infalling gas and dust, causing them to shine brightly as active galactic nuclei (AGN).

    This AGN pair is the closest one detected in the local universe using multiwavelength (visible and X-ray light) observations. While several dozen “dual” black holes have been found before, their separations are typically much greater than what was discovered in the gas-rich galaxy MCG-03-34-64. Astronomers using radio telescopes have observed one pair of binary black holes in even closer proximity than in MCG-03-34-64, but without confirmation in other wavelengths.

    AGN binaries like this were likely more common in the early universe when galaxy mergers were more frequent. This discovery provides a unique close-up look at a nearby example, located about 800 million light-years away.

    A Hubble Space Telescope visible-light image of the galaxy MCG-03-34-064. Hubble’s sharp view reveals three distinct bright spots embedded in a white ellipse at the galaxy’s center (expanded in an inset image at upper right). Two of these bright spots are the source of strong X-ray emission, a telltale sign that they are supermassive black holes. The black holes shine brightly because they are converting infalling matter into energy, and blaze across space as active galactic nuclei. Their separation is about 300 light-years. The third spot is a blob of bright gas. The blue streak pointing to the 5 o’clock position may be a jet fired from one of the black holes. The black hole pair is a result of a merger between two galaxies that will eventually collide. NASA, ESA, Anna Trindade Falcão (CfA); Image Processing: Joseph DePasquale (STScI)
    Download this image

    The discovery was serendipitous. Hubble’s high-resolution imaging revealed three optical diffraction spikes nested inside the host galaxy, indicating a large concentration of glowing oxygen gas within a very small area. “We were not expecting to see something like this,” said Anna Trindade Falcão of the Center for Astrophysics | Harvard & Smithsonian in Cambridge, Massachusetts, lead author of the paper published today in The Astrophysical Journal. “This view is not a common occurrence in the nearby universe, and told us there’s something else going on inside the galaxy.”

    Diffraction spikes are imaging artifacts caused when light from a very small region in space bends around the mirror inside telescopes.

    Falcão’s team then examined the same galaxy in X-rays light using the Chandra observatory to drill into what’s going on. “When we looked at MCG-03-34-64 in the X-ray band, we saw two separated, powerful sources of high-energy emission coincident with the bright optical points of light seen with Hubble. We put these pieces together and concluded that we were likely looking at two closely spaced supermassive black holes,” said Falcão.

    In a surprise finding, astronomers, using NASA’s Hubble Space Telescope have discovered that the jet from a supermassive black hole at the core of M87, a huge galaxy 54 million light years away, seems to cause stars to erupt along its trajectory. The stars, called novae, are not caught inside the jet, but in a dangerous area near it.
    NASA’s Goddard Space Flight Center; Lead Producer: Paul Morris

    To support their interpretation, the researchers used archival radio data from the Karl G. Jansky Very Large Array near Socorro, New Mexico. The energetic black hole duo also emits powerful radio waves. “When you see bright light in optical, X-rays, and radio wavelengths, a lot of things can be ruled out, leaving the conclusion these can only be explained as close black holes. When you put all the pieces together it gives you the picture of the AGN duo,” said Falcão.

    The third source of bright light seen by Hubble is of unknown origin, and more data is needed to understand it. That might be gas that is shocked by energy from a jet of ultra high-speed plasma fired from one of the black holes, like a stream of water from a garden hose blasting into a pile of sand.

    “We wouldn’t be able to see all of these intricacies without Hubble’s amazing resolution,” said Falcão.

    The two supermassive black holes were once at the core of their respective host galaxies. A merger between the galaxies brought the black holes into close proximity. They will continue to spiral closer together until they eventually merge — in perhaps 100 million years — rattling the fabric of space and time as gravitational waves.

    The National Science Foundation’s Laser Interferometer Gravitational-Wave Observatory (LIGO) has detected gravitational waves from dozens of mergers between stellar-mass black holes. But the longer wavelengths resulting from a supermassive black hole merger are beyond LIGO’s capabilities. The next-generation gravitational wave detector, called the LISA (Laser Interferometer Space Antenna) mission, will consist of three detectors in space, separated by millions of miles, to capture these longer wavelength gravitational waves from deep space. ESA (European Space Agency) is leading this mission, partnering with NASA and other participating institutions, with a planned launch in the mid-2030s.

    NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science from Cambridge, Massachusetts and flight operations from Burlington, Massachusetts. Northrop Grumman Space Technologies in Redondo Beach, California was the prime contractor for the spacecraft.

    The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.

    Facebook logo @NASAHubble

    @NASAHubble

    Instagram logo @NASAHubble

    Media Contacts:

    Claire Andreoli
    NASA’s Goddard Space Flight Center, Greenbelt, MD
    claire.andreoli@nasa.gov

    Ray Villard
    Space Telescope Science Institute, Baltimore, MD

    Science Contact:

    Anna Trindade Falcão
    Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA

    Share

    Details

    Last Updated

    Sep 09, 2024

    Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center

    Related Terms Keep Exploring Discover More Topics From Hubble

    Hubble Space Telescope

    Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.


    Galaxy Details and Mergers


    Monster Black Holes Are Everywhere


    Hubble’s Galaxies

    Categories: NASA

    A particularly active 'aurora season' could be just weeks away

    Space.com - Mon, 09/09/2024 - 10:00am
    September could be a prime time to see vibrant auroras, thanks to a quirk of Earth's tilt that leads to more intense geomagnetic activity around the equinox.
    Categories: Astronomy

    A New Quantum Cheshire Cat Thought Experiment Is Out of the Box

    Scientific American.com - Mon, 09/09/2024 - 9:00am

    The spin of a particle seems to detach and move without a body—a strange experimental observation that’s stirring up debate

    Categories: Astronomy

    Best Transformers shows of all time

    Space.com - Mon, 09/09/2024 - 8:59am
    From the original series to the modern day, we've ranked all the Transformers animated TV series from worst to best.
    Categories: Astronomy

    The biggest galaxies live in our universe's supercluster 'cities'

    Space.com - Mon, 09/09/2024 - 8:00am
    Machine learning algorithms analyzed millions of galaxies to reveal where the biggest ones are.
    Categories: Astronomy

    We Must Secure Our Future in a Hotter, More Dangerous World

    Scientific American.com - Mon, 09/09/2024 - 7:00am

    Defending the U.S. is much more complicated in an era of climate change

    Categories: Astronomy

    Watch a 100,000-mile-high tower of plasma erupt from the sun in this stunning video

    Space.com - Mon, 09/09/2024 - 6:00am
    Astrophotographer Mark Johnston got a front row seat to an epic fireworks show when he filmed a 100,000-mile-high tower of plasma erupting from the sun.
    Categories: Astronomy

    Invasive Jellyfish Clones Overrunning British Columbian Lakes; Measles Cases Increasing in Oregon

    Scientific American.com - Mon, 09/09/2024 - 6:00am

    This week’s news roundup: Jellyfish clones are multiplying in British Columbia’s lakes, measles cases are on the rise in Oregon, and a new study finds cell phones aren’t linked to brain cancer.

    Categories: Astronomy

    Goodnight, Cluster: brilliant end to trailblazing mission

    ESO Top News - Mon, 09/09/2024 - 2:00am

    The first satellite in ESA’s Cluster quartet safely came back down to Earth last night in a world-first ‘targeted reentry’, marking a brilliant end to this remarkable mission.

    The spacecraft, dubbed ‘Salsa’ (Cluster 2), reentered Earth’s atmosphere at 20:47 CEST on 8 September 2024 over the South Pacific Ocean. In this region, any risk of fragments reaching land are absolutely minimised.

    During the last two decades Cluster has spent in space, it has provided invaluable data on how the Sun interacts with Earth’s magnetic field, helping us better understand and forecast space weather. With this first-ever targeted reentry, Cluster will go down in history for a second reason – helping ESA become a world-leader in sustainable space exploration.

    Categories: Astronomy

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

    Universe Today - Sun, 09/08/2024 - 8:47pm

    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.

    The team was led by Jessica Speedie, an astronomy and astrophysics Ph.D. candidate at the University of Victoria. She was joined by colleagues from the Kavli Institute for Astronomy and Astrophysics (KIAA-PKU), the Center for Simulational Physics (CSP-UGA), the Cambridge Institute of Astronomy, the Centre de Recherche Astrophysique de Lyon (CNSA-CRAL), the Institute of Astronomy and Astrophysics (ASIAA), the Department of Earth, Atmospheric, and Planetary Sciences (MIT EAPS), the National Astronomical Observatory of Japan (NAOJ), the European Southern Observatory (ESO), and multiple universities and observatories.

    The paper that details their research, “Gravitational instability in a planet-forming disk,” was recently published in the journal Nature.

    Located in the Atacama desert in the Chilean Andes, ALMA is the largest radio telescope in the world dedicated to studying the parts of the Universe that are otherwise invisible to astronomers. This includes cold dust clouds in space, protoplanetary disks, and some of the earliest galaxies in the Universe, which are only visible at millimeter and submillimeter wavelengths. Using ALMA, Speedie and her colleagues observed the well-characterized protoplanetary disk around AB Aurigae, a young star system (4 million years old) located about 530 light-years from Earth.

    The star is a pre-main sequence A-type star (blue-white) approximately 2.5 times the size of our Sun and about 2.4 times as massive. Beginning in 2017, scientists at ALMA began observing the star’s protoplanetary disk to learn more about planet formation in young star systems. Since then, astronomers have observed several developing protoplanets forming in AB Aurigae’s disk, as well as a gas giant nine times the mass of Jupiter that was confirmed in 2022. These appear as clumps within the protoplanetary disk’s spiral arms, rotating counterclockwise around the star.

    The detection of these bodies around such a young star raised doubts about the “bottom-up” process. According to this model, these protoplanets did not have nearly enough time to become as large as they have. Along with her PhD advisor Ruobing Dong, Speedie and their team were determined to study how the gas in the system’s vast spiral arms is moving. ALMA’s sensitivity and high velocity resolution was crucial to that task and enabled the team to probe the gas deep within the disk and measure its motion precisely.

    Dr. Cassandra Hall, an Assistant Professor of Computational Astrophysics at the University of Georgia was also a co-author on the research. Four years ago, Hall led a study where she and her colleagues (which included Dong and other members of Speedie’s team) simulated how a gravitationally unstable disk would behave. As she indicated in a NRAO press release:

    “Disks that are gravitationally unstable should have distinctive ‘wiggles’ in their velocity field, unlike disks that are stable. Back in 2020, we performed some of the most advanced simulations in the world to predict the existence of this hallmark signature of gravitational instability. It was clear, it was testable, and it was a bit scary – if we didn’t find it, then something had to be very, very wrong with our understanding of these disks.”

    Spiral arms form in a protoplanetary disk when the disk-to-star mass ratio is sufficiently high. Over time, changes in density lead to changes in gravity, which causes variations in the velocities of gas in and around the spiral arms. These variations in velocity are seen as “wiggles,” and the magnitude can be used to infer the mass ratio between the host star and the material in its disk. Using ALMA’s array of radio antennas, Speedie and her team mapped the velocity of carbon monoxide isotopes within the disk’s spiral arms and looked for indications of the predicted “wiggles.”

    These measurements yielded a three-dimensional rectangular “data cube” that mapped gas velocity and position within the protoplanetary disk along the observatory’s line of sight. As is customary with ALMA’s interferometry measurements, the data was parsed into “slices” (or strategically oriented cuts), allowing Speedie and her team to conclusively identify the velocity wiggle indicating gravitational instability. This constitutes the first direct observational confirmation that the “top-down” pathway to planet formation is correct.

    What’s more, it indicates that planetary systems may form much faster than previously thought, which could have significant implications for astrogeology and exoplanet research. As Speedie explained, Hall’s work, ALMA’s sensitivity, and the quality data products it created for them were what made this discovery possible:

    “This is a classic science story of, ‘we predicted it, and then we found it’. The Hall-mark of gravitational instability. We worked with one of the deepest ALMA observations taken with such high-velocity resolution toward a single protoplanetary disk to date. The ALMA data provides a clear diagnosis of gravitational instability in action. There is no other mechanism we know of that can create the global architecture of spiral structure and velocity patterns that we observe.”

    In the near future, Speedie and her colleagues plan to continue using ALMA to learn more about how planetary systems form around young stars. As part of the NFS/NRAO ALMA ambassador program, Speedie is training alongside other postdoctoral students and early career astronomers to share ALMA’s resources and capabilities with the wider astronomical community.

    Further Reading: NRAO, Nature

    The post ALMA Detects Hallmark “Wiggle” of Gravitational Instability in Planet-Forming Disk appeared first on Universe Today.

    Categories: Astronomy