‘Campfires’ Spotted on the Sun in First Solar Orbiter Images – The Closest Images to the Sun


This animation shows a series of views of the Sun captured with the Extreme Ultraviolet Imager (EUI) on ESA/NASA’s Solar Orbiter on May 30, 2020. They show the appearance of the Sun at a wavelength of 17 nanometers, which is in the extreme ultraviolet region of the electromagnetic spectrum. Images at this wavelength reveal the Sun’s upper atmosphere, the corona, with a temperature of over a million degrees. Credit: Solar Orbiter/EUI Team (ESA & NASA); CSL, IAS, MPS, PMOD/WRC, ROB, UCL/MSSL

The first images from ESA/[{” attribute=””>NASA’s Solar Orbiter are now available to the public, including the closest pictures ever taken of the Sun.

Solar Orbiter is an international collaboration between the European Space Agency, or ESA, and NASA, to study our closest star, the Sun. Launched on Feb. 9, 2020 (EST), the spacecraft completed its first close pass of the Sun in mid-June.

“These unprecedented pictures of the Sun are the closest we have ever obtained,” said Holly Gilbert, NASA project scientist for the mission at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “These amazing images will help scientists piece together the Sun’s atmospheric layers, which is important for understanding how it drives space weather near the Earth and throughout the solar system.”

“We didn’t expect such great results so early,” said Daniel Müller, ESA’s Solar Orbiter project scientist. “These images show that Solar Orbiter is off to an excellent start.”

Solar Orbiter Spots Campfires

Solar Orbiter spots ‘campfires’ on the Sun. Locations of campfires are annotated with white arrows. Credit: Solar Orbiter/EUI Team (ESA & NASA); CSL, IAS, MPS, PMOD/WRC, ROB, UCL/MSSL

Getting to this point was no simple feat. The novel coronavirus forced mission control at the European Space Operations Center, or ESOC, in Darmstadt, Germany to close down completely for more than a week. During commissioning, the period when each instrument is extensively tested, ESOC staff were reduced to a skeleton crew. All but essential personnel worked from home.

“The pandemic required us to perform critical operations remotely – the first time we have ever done that,” said Russell Howard, principal investigator for one of Solar Orbiter’s imagers.

But the team adapted, even readying for an unexpected encounter with comet ATLAS’s ion and dust tails on June 1 and 6, respectively. The spacecraft completed commissioning just in time for its first close solar pass on June 15. As it flew within 48 million miles of the Sun, all 10 instruments flicked on, and Solar Orbiter snapped the closest pictures of the Sun to date. (Other spacecraft have been closer, but none have carried Sun-facing imagers.)

Solar Orbiter carries six imaging instruments, each studying a different aspect of the Sun. Normally, the first images of a spacecraft confirm that the instruments are working; scientists do not expect new discoveries from them. But the Extreme Ultraviolet Imager, or EUI, on Solar Orbiter returned data hinting at solar features never before seen in such detail.

Lead researcher David Berghmans, an astrophysicist at the Royal Observatory of Belgium in Brussels, points to what he calls “campfires” dotting the Sun in EUI images.

“The campfires we’re talking about here are the little nephews of solar flares, at least a million, maybe a billion times smaller,” Berghmans said. “When you look at the new high resolution EUI images, they are literally everywhere we look.”

First images from the solar and heliospheric imager

The first images from the Solar and Heliospheric Imager, or SoloHI instrument, reveal zodiacal light (the bright spot of light on the right protruding towards the center). Mercury is also visible as a bright dot in the left image. The right light feature on the very edge of the image is a deflector illuminated by reflections from the spacecraft’s solar panel. Credit: Solar Orbiter/SoloHI team (ESA and NASA), NRL

It is not yet known what these campfires are or how they correspond to the solar brightening observed by other spacecraft. But it’s possible they’re mini-explosions known as nanoflares – tiny but ubiquitous sparks theorized to help heat the Sun’s outer atmosphere, or corona, to its temperature 300 times hotter than the Sun. solar surface.

To be sure, scientists need a more accurate measurement of campfire temperatures. Fortunately, the Spectral Imaging of the Coronal Environment, or SPICE, instrument, also on Solar Orbiter, does just that.

We therefore look forward to our next set of data,” said Frédéric Auchère, principal investigator for SPICE operations at the Institute for Space Astrophysics in Orsay, France. “The hope is to detect nanoflares for sure and quantify their role in coronal heating.”

Other images of the spacecraft show additional promise for later in the mission, when Solar Orbiter will be closer to the Sun.

The Solar and Heliospheric Imager, or SoloHI, led by Russell Howard of the Naval Research Laboratory in Washington, DC, revealed so-called zodiacal light, sunlight reflecting off interplanetary dust – light so faint that the face bright from the Sun normally darkens it. To see it, SoloHI had to reduce the Sun’s light to one trillionth of its original luminosity.

“The images produced such a perfect, clean zodiac light pattern,” Howard said. “It gives us a lot of confidence that we will be able to see solar wind structures as we get closer to the Sun.”

Polarimetric and helioseismic imager

This animation shows a sequence of images from the Polarimetric and Helioseismic Imager (PHI) on ESA/NASA’s Solar Orbiter. PHI measures the magnetic field near the surface of the Sun and allows the investigation of the interior of the Sun via the technique of helioseismology. Credit: Solar Orbiter/Team PHI/ESA and NASA

Images from the Polar and Helioseismic Imager, or PHI, showed it is also ready for further observations. PHI maps the Sun’s magnetic field, with particular emphasis on its poles. It will have its finest hour later in the mission as Solar Orbiter gradually tilts its orbit 24 degrees above the plane of the planets, giving it an unprecedented view of the Sun’s poles.

“The magnetic structures we see on the visible surface show that PHI is receiving high-quality data,” said Sami Solanki, PHI principal investigator at the Max Planck Institute for Solar System Research in Göttingen, Germany. “We’re ready for big science as more of the Sun’s poles appear.”

Today’s post highlights Solar Orbiter’s imagers, but the mission’s four in-situ instruments also revealed early results. In situ instruments measure the space environment immediately surrounding the spacecraft. The Solar Wind Analyzer, or SWA instrument, has shared the first dedicated measurements of heavy ions (carbon, oxygen, silicon, iron and others) in the solar wind from the inner heliosphere.

The new data, including films and images with detailed descriptions, can be viewed in the ESA gallery.

Solar Orbiter is an international cooperation mission between the European Space Agency and NASA. The European Space Operations Center (ESOC) in Germany operates Solar Orbiter. Solar Orbiter was built by Airbus Defense and Space and contains 10 instruments: nine provided by ESA Member States and ESA. NASA provided one instrument, SoloHI, hardware and sensors for three other instruments, and the Atlas V 411 launcher. The European Space Astronomy Center (ESAC) in Spain is leading the science operations.

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