In February of this year, the European Space Agency’s (ESA) Solar Orbiter launched from Cape Canaveral in Florida and headed straight for the Sun. Now, the tough solar explorer has sent back its first images, which reveal previously unseen “campfires” on the Sun’s surface.
When the Solar Orbiter snapped the photos that captured the small fiery disruptions, it was 55 million miles away from the Sun, a relatively close distance considering how much heat our star throws off. In fact, while NASA’s Parker Solar Probe represents the closest a vessel from earth has ever gotten to the Sun, the pictures returned by Solar Orbiter are the closest shots ever taken of the giant fireball.
So, What Are the “Campfires?”
“The campfires are little relatives of the solar flares that we can observe from Earth, million or billion times smaller,” says David Berghmans of the Royal Observatory of Belgium (ROB), Principal Investigator of the EUI instrument, which takes high-resolution images of the lower layers of the Sun’s atmosphere, known as the solar corona. “The Sun might look quiet at first glance, but when we look in detail, we can see those miniature flares everywhere we look.”
It’s still unclear whether the campfires eventually grow into solar flares, which are massive explosions of energy that stream out into space and enhance the solar wind, or if they exist unto themselves.
Hot Air
One theory is that the campfires might contribute to the coronal heating in part of a still unknown mechanism that heats the Sun’s outermost layer (the corona) to temperatures higher than a million degrees Celsius, which is quite a bit more blistering than the Sun’s surface temperature of 5500 degrees celsius.
While these first images have certainly caused a stir in the astronomy community, they represent only the start of the Solar Orbiter’s mission, which is set to return better and better images of our star as it gets closer, while also revealing more details about the solar wind using its ten onboard instruments.
“We are all really excited about these first images — but this is just the beginning,” adds Daniel. “Solar Orbiter has started a grand tour of the inner Solar System and will get much closer to the Sun within less than two years. Ultimately, it will get as close as 42 million km, which is almost a quarter of the distance from Sun to Earth.”
Check out more images from the Orbiter in the gallery below selected from the ESA, or see all the photos at their online gallery.
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The Extreme Ultraviolet Imager (EUI) on ESA’s Solar Orbiter spacecraft took these images on 30 May 2020. They show the Sun’s appearance at a wavelength of 17 nanometers, which is in the extreme ultraviolet region of the electromagnetic spectrum. Images at this wavelength reveal the upper atmosphere of the Sun, the corona, with a temperature of around 1 million degrees.
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A high-resolution image from the Extreme Ultraviolet Imager (EUI) on ESA’s Solar Orbiter spacecraft, taken with the HRIEUV telescope on 30 May 2020. These images show the Sun’s appearance at a wavelength of 17 nanometers, which is in the extreme ultraviolet region of the electromagnetic spectrum. Images at this wavelength reveal the upper atmosphere of the Sun, the corona, with a temperature of around 1 million degrees.
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These solar images have been produced by the high resolution imager, HRILYA telescope, which is part of the Extreme Ultraviolet Imager (EUI) instrument on ESA’s Solar Orbiter spacecraft. The images show the solar surface in a particular ultraviolet wavelength that is produced by hydrogen, the most abundant chemical element in the Universe.
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The ‘network’ structure seen in the images is characteristic of a region of the solar atmosphere known as the chromosphere. This section of the Sun’s lower atmosphere has a temperature of about ten-thousand to hundred-thousand degrees Kelvin. It is an important transition region in the solar atmosphere where the electrically charged gas, known as plasma, is increasingly dominated by the magnetic field of the Sun.
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This image is a view of the Sun taken by the Polarimetric and Helioseismic Imager (PHI) Full Disc Telescope on ESA’s Solar Orbiter on 18 June 2020. This is a visible light image and represents what we would see with the naked eye. There are no sunspots visible because the Sun is displaying only low levels of magnetic activity at the moment.
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The full disc image below shows a map of magnetic propertied for the whole Sun based on data from the Polarimetric and Helioseismic Imager (PHI) on ESA’s Solar Orbiter. Taken on 18 June 2020, there is a large magnetically active region in the lower right-hand quadrant of the Sun.
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This image is a ‘tachogram’ of the Sun, taken with the Polarimetric and Helioseismic Imager (PHI) Full Disc Telescope on ESA’s Solar Orbiter on 18 June 2020. It shows the line of sight velocity of the Sun, with the blue side turning to us and the red side turning away.
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An image of the Sun’s corona obtained with the Metis instrument on ESA’s Solar Orbiter. This image comes from the instrument’s first light, which was obtained on 15 May 2020, and was taken in visible light (580-640 nm). It shows the two bright equatorial streamers and fainter polar regions that are characteristic of the solar corona during times of minimal magnetic activity.
