On March 26, ESA’s Solar Orbiter made its closest approach to the sun so far. It ventured inside Mercury’s orbit and was about a third of the distance between Earth and the sun. It was hot but worth it.
The main mission of Solar Orbiter is to understand the link between the sun and its heliosphere, and new images of the close approach help build this understanding.
According to the ESA, the Solar Orbiter is the most complex scientific laboratory ever sent to the sun. It carries a suite of robust instruments, including a magnetometer, the Extreme Ultraviolet Imager, the Solar Wind Plasma Analyzer, and more. Its wide range of instruments allows it to observe solar events in multiple ways.
The spacecraft takes advantage of getting as close to the sun as possible. But close approaches make the Solar Orbiter hot. The spacecraft’s first line of defense is its heat shield. It is a multi-layered titanium device mounted on an aluminum honeycomb backing, with carbon fiber skins designed to conduct heat away. Between all of this and the body of the spacecraft, there are another 28 layers of insulation. During this approach, its heat shield reached 500 degrees Celsius (932 degrees Fahrenheit.)
Protected from the heat, the Solar Orbiter collected a lot of data in its approach. Scientists need more time to work with and understand, but the images and videos are immediately engaging. One solar feature that has caught everyone’s attention is the “space hedgehog”.
Thanks to a bit of luck, the sun put on a show as Solar Orbiter approached. There was solar flares, and even an Earth-directed coronal mass ejection (CME). The Solar Orbiter has several remote sensing instruments, and the scientists used them to predict when the CME would reach Earth. They released their forecast on social media, and 18 hours later, ground observers were prepared to witness the resulting aurora. The ESA has published a graphic to explain how it happened.
The following video features flare and CME images from three of Solar Orbiter’s instruments: the Extreme Ultraviolet Imager, Metis Coronagraph, and SoloHI, Solar Orbiter’s Heliospheric Imager.
The orbiter also gave us our highest resolution image of the sun’s south pole.
Scientists are interested in the poles of the sun because of how the sun’s magnetic fields work. Magnetic fields create strong but temporary active regions on the surface of the sun, and the fields are swept up and down to the poles before being engulfed by the sun again. Scientists believe they act as seeds for the next solar activity. The detailed images of the sun’s south pole should help researchers understand how it all works.
In the video of the sun South Pole, the brighter regions are mostly magnetic loops rising from the interior of the sun. They are called closed magnetic field lines because the particles find it difficult to cross them. Instead, the particles are trapped and emit extreme ultraviolet radiation, which Solar Orbiter’s Extreme Ultraviolet Imager (EUI) is poised to capture.
The darkest regions of the video are where the sun magnetic field the lines are open. Instead of being closed to particles and trapping them, gases can escape into space from these darker regions. This creates solar wind.
The orbiter also captured images and data from a March 2 solar flare. The spacecraft’s Extreme Ultraviolet Imager (EUI) and Telescope/X-Ray Spectrometer (STIX) instruments captured the flare as solar atmospheric gases reached temperatures of about one million degrees C (1 800,000 F) and emitted extreme ultraviolet energy and X-rays.
In the gif below, low energy x-rays are shown in red and higher energy x-rays are shown in blue.
There’s a lot more to come from the Solar Orbiter. Over the next four years, the spacecraft will encounter Venus for the fourth and fifth times. Each time it does, it will increase its tilt, giving it a more direct view of the sun’s poles. By December 2026, it will be inclined in orbit at 24 degrees, marking the start of the spacecraft’s “high latitude” mission.
These high latitude observations will give scientists a direct view of the poles. The ESA says these vantage points are crucial to unraveling the sun’s complex magnetic polar environment. This could help unravel the mystery of the sun’s 11-year cycles.
“We are delighted with the quality of the data from our first perihelion,” said Daniel Müller, ESA project scientist for Solar Orbiter. “It’s almost hard to believe this is just the beginning of the mission. We’re going to be really busy.”
Quote: Solar Orbiter images of the sun are just as dramatic as you’d hoped (2022, May 26) Retrieved May 26, 2022, from https://phys.org/news/2022-05-solar-biter-pictures-sun -bit .html
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