Jump to content

Recommended Posts

Posted
Tiny_magnetic_episodes_may_have_large_co Video: 00:42:00

ESA’s Solar Orbiter may have taken another step towards solving the eighty-year-old mystery of why the Sun’s outer atmosphere is so hot.

On 3 March 2022, just a few months into Solar Orbiter’s nominal mission, the spacecraft’s Extreme Ultraviolet Imager (EUI) returned data showing for the first time that a magnetic phenomenon called reconnection was taking place persistently on tiny scales.

At that time, the spacecraft was about halfway between the Earth and the Sun. This enabled coordinated observations with NASA’s Solar Dynamics Observatory (SDO) and Interface Region Imaging Spectrograph (IRIS) missions. The data from the three missions was then combined during the analysis.

Magnetic reconnection occurs when a magnetic field changes itself into a more stable configuration. It is a fundamental energy release mechanism in superheated gasses known as plasmas and is believed to be the major mechanism for powering large-scale solar eruptions. This makes it the direct cause of space weather, and a prime candidate for the mysterious heating of the Sun’s outer atmosphere.

It has been known since the 1940s that the Sun’s outer atmosphere, called the corona, is much hotter than the Sun’s surface. While the surface glows at around 5 500°C, the corona is a rarified gas of around 2 million °C. How the Sun injects energy into its atmosphere to heat it to this tremendous temperature has been a major puzzle ever since.

In the past, magnetic reconnection has usually been seen during large-scale, explosive phenomena. However, the new result presents ultra-high-resolution observations of persistent small-scale (around 390 km across) reconnection in the corona. These are revealed to be a long-lived ‘gentle’ sequence compared to sudden explosive releases of energy that reconnection is usually associated with.

The 3 March 2022 event took place over the period of one hour. The temperatures around the point of the magnetic field where the magnetic field intensity drops to zero, known as the null-point, sustained itself at around 10 million °C, and generated an outflow of material that came in the form of discrete ‘blobs’ travelling away from the null point with a speed of around 80 km/s.

In addition to this continuous outflow, an explosive episode also took place around this null point, and lasted for four minutes.

Solar Orbiter’s results suggest that magnetic reconnection, at scales that were previously too small to be resolved, proceeds continually in both gentle and explosive ways. This is importantly because it means that reconnection can therefore persistently transfer mass and energy to the overlying corona, contributing to heating it.

These observations also suggest that even smaller and more frequent magnetic reconnections await discovery. The goal is now to observe these with EUI at even higher spatio-temporal resolution in the future around Solar Orbiter’s closest approaches to estimate what fraction of the corona’s heat may be transferred in this way.

Solar Orbiter’s most recent closest passage to the Sun took place on 10 April 2023. At that time, the spacecraft was just 29 percent the Earth’s distance from the Sun.

Solar Orbiter is a space mission of international collaboration between ESA and NASA, operated by ESA.

These results are published in Nature Communications in a paper titled Ultra-high-resolution Observations of Persistent Null-point Reconnection in the Solar Corona. Principal author Prof. Xin Cheng, Nanjing University, China, and Max Planck Institute for Solar System Research, Göttingen, Germany led an international team of 24 collaborators.

View the full article

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Topics

    • By NASA
      Explore This Section Webb News Latest News Latest Images Blog (offsite) Awards X (offsite – login reqd) Instagram (offsite – login reqd) Facebook (offsite- login reqd) Youtube (offsite) Overview About Who is James Webb? Fact Sheet Impacts+Benefits FAQ Science Overview and Goals Early Universe Galaxies Over Time Star Lifecycle Other Worlds Observatory Overview Launch Deployment Orbit Mirrors Sunshield Instrument: NIRCam Instrument: MIRI Instrument: NIRSpec Instrument: FGS/NIRISS Optical Telescope Element Backplane Spacecraft Bus Instrument Module Multimedia About Webb Images Images Videos What is Webb Observing? 3d Webb in 3d Solar System Podcasts Webb Image Sonifications Team International Team People Of Webb More For the Media For Scientists For Educators For Fun/Learning 5 Min Read NASA Webb Explores Effect of Strong Magnetic Fields on Star Formation
      An image of the Milky Way captured by the MeerKAT radio telescope array puts the James Webb Space Telescope’s image of the Sagittarius C region in context. Full image below. Credits:
      NASA, ESA, CSA, STScI, SARAO, Samuel Crowe (UVA), John Bally (CU), Ruben Fedriani (IAA-CSIC), Ian Heywood (Oxford) Follow-up research on a 2023 image of the Sagittarius C stellar nursery in the heart of our Milky Way galaxy, captured by NASA’s James Webb Space Telescope, has revealed ejections from still-forming protostars and insights into the impact of strong magnetic fields on interstellar gas and the life cycle of stars.  
      “A big question in the Central Molecular Zone of our galaxy has been, if there is so much dense gas and cosmic dust here, and we know that stars form in such clouds, why are so few stars born here?” said astrophysicist John Bally of the University of Colorado Boulder, one of the principal investigators. “Now, for the first time, we are seeing directly that strong magnetic fields may play an important role in suppressing star formation, even at small scales.”
      Detailed study of stars in this crowded, dusty region has been limited, but Webb’s advanced near-infrared instruments have allowed astronomers to see through the clouds to study young stars like never before.
      “The extreme environment of the galactic center is a fascinating place to put star formation theories to the test, and the infrared capabilities of NASA’s James Webb Space Telescope provide the opportunity to build on past important observations from ground-based telescopes like ALMA and MeerKAT,” said Samuel Crowe, another principal investigator on the research, a senior undergraduate at the University of Virginia and a 2025 Rhodes Scholar.
      Bally and Crowe each led a paper published in The Astrophysical Journal.
      Image A: Milky Way Center (MeerKAT and Webb)
      An image of the Milky Way captured by the MeerKAT (formerly the Karoo Array Telescope) radio telescope array puts the James Webb Space Telescope’s image of the Sagittarius C region in context. Like a super-long exposure photograph, MeerKAT shows the bubble-like remnants of supernovas that exploded over millennia, capturing the dynamic nature of the Milky Way’s chaotic core. At the center of the MeerKAT image the region surrounding the Milky Way’s supermassive black hole blazes bright. Huge vertical filamentary structures echo those captured on a smaller scale by Webb in Sagittarius C’s blue-green hydrogen cloud. NASA, ESA, CSA, STScI, SARAO, Samuel Crowe (UVA), John Bally (CU), Ruben Fedriani (IAA-CSIC), Ian Heywood (Oxford) Image B: Milky Way Center (MeerKAT and Webb), Labeled
      The star-forming region Sagittarius C, captured by the James Webb Space Telescope, is about 200 light-years from the Milky Way’s central supermassive black hole, Sagittarius A*. The spectral index at the lower left shows how color was assigned to the radio data to create the image. On the negative end, there is non-thermal emission, stimulated by electrons spiraling around magnetic field lines. On the positive side, thermal emission is coming from hot, ionized plasma. For Webb, color is assigned by shifting the infrared spectrum to visible light colors. The shortest infrared wavelengths are bluer, and the longer wavelengths appear more red. NASA, ESA, CSA, STScI, SARAO, Samuel Crowe (UVA), John Bally (CU), Ruben Fedriani (IAA-CSIC), Ian Heywood (Oxford) Using Infrared to Reveal Forming Stars
      In Sagittarius C’s brightest cluster, the researchers confirmed the tentative finding from the Atacama Large Millimeter Array (ALMA) that two massive stars are forming there. Along with infrared data from NASA’s retired Spitzer Space Telescope and SOFIA (Stratospheric Observatory for Infrared Astronomy) mission, as well as the Herschel Space Observatory, they used Webb to determine that each of the massive protostars is already more than 20 times the mass of the Sun. Webb also revealed the bright outflows powered by each protostar.
      Even more challenging is finding low-mass protostars, still shrouded in cocoons of cosmic dust. Researchers compared Webb’s data with ALMA’s past observations to identify five likely low-mass protostar candidates.
      The team also identified 88 features that appear to be shocked hydrogen gas, where material being blasted out in jets from young stars impacts the surrounding gas cloud. Analysis of these features led to the discovery of a new star-forming cloud, distinct from the main Sagittarius C cloud, hosting at least two protostars powering their own jets.
      “Outflows from forming stars in Sagittarius C have been hinted at in past observations, but this is the first time we’ve been able to confirm them in infrared light. It’s very exciting to see, because there is still a lot we don’t know about star formation, especially in the Central Molecular Zone, and it’s so important to how the universe works,” said Crowe.
      Magnetic Fields and Star Formation
      Webb’s 2023 image of Sagittarius C showed dozens of distinctive filaments in a region of hot hydrogen plasma surrounding the main star-forming cloud. New analysis by Bally and his team has led them to hypothesize that the filaments are shaped by magnetic fields, which have also been observed in the past by the ground-based observatories ALMA and MeerKAT (formerly the Karoo Array Telescope).
      “The motion of gas swirling in the extreme tidal forces of the Milky Way’s supermassive black hole, Sagittarius A*, can stretch and amplify the surrounding magnetic fields. Those fields, in turn, are shaping the plasma in Sagittarius C,” said Bally.
      The researchers think that the magnetic forces in the galactic center may be strong enough to keep the plasma from spreading, instead confining it into the concentrated filaments seen in the Webb image. These strong magnetic fields may also resist the gravity that would typically cause dense clouds of gas and dust to collapse and forge stars, explaining Sagittarius C’s lower-than-expected star formation rate. 
      “This is an exciting area for future research, as the influence of strong magnetic fields, in the center of our galaxy or other galaxies, on stellar ecology has not been fully considered,” said Crowe.  
      The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
      Downloads
      Click any image to open a larger version.
      View/Download all image products at all resolutions for this article from the Space Telescope Science Institute.
      View/Download the science paper led by Bally from the The Astrophysical Journal.
      View/Download the science paper led by Crowe from the The Astrophysical Journal.
      Media Contacts
      Laura Betz – laura.e.betz@nasa.gov
      NASA’s Goddard Space Flight Center, Greenbelt, Md.
      Leah Ramsay – lramsay@stsci.edu
      Space Telescope Science Institute, Baltimore, Md.
      Christine Pulliam – cpulliam@stsci.edu
      Space Telescope Science Institute, Baltimore, Md.
      Related Information
      Read more: press releases about the center of the Milky Way
      NASA’s Universe of Learning: ViewSpace Interactive image tour of the center of the Milky Way
      Learn more about the Milky Way and Sagittarius Constellation
      More Webb News
      More Webb Images
      Webb Science Themes
      Webb Mission Page
      Related For Kids
      What Is a Nebula?
      What Is a Galaxy?
      What is the Webb Telescope?
      SpacePlace for Kids
      En Español
      ¿Qué es una nebulosa?
      ¿Qué es una galaxia?
      Ciencia de la NASA
      NASA en español 
      Space Place para niños
      Keep Exploring Related Topics
      James Webb Space Telescope


      Webb is the premier observatory of the next decade, serving thousands of astronomers worldwide. It studies every phase in the…


      Stars



      Galaxies



      Universe


      Share








      Details
      Last Updated Apr 02, 2025 Editor Marty McCoy Contact Laura Betz laura.e.betz@nasa.gov Related Terms
      James Webb Space Telescope (JWST) Astrophysics Galaxies Galaxies, Stars, & Black Holes Goddard Space Flight Center Protostars Science & Research Stars The Milky Way The Universe View the full article
    • By Amazing Space
      LIVE NOW: Live Close Up Video Of The Sun - 1st April
    • By Amazing Space
      The Sun Today - 1st April - Close Up View.
    • By Amazing Space
      LIVE NOW: Live Close Up Video Of The SUn
    • By Amazing Space
      LIVE NOW: Live Close Up Video Of The SUn
  • Check out these Videos

×
×
  • Create New...