Solar Orbiter Observes its First Cme (Planetary Science)

The images and animations of the first coronal mass ejections, or Cme for short, taken by the instruments on board the Solar orbiter probe still in full test have been released by the European Space Agency. Among them also the Italian coronographer Metis. With the comment of Silvano Fineschi, Inaf scientific manager for Solar Orbiter

Solar Orbiter was launched on February 10, 2020 and is currently in the cruise phase, ahead of the main science mission that will begin next November. While the four in-situ instruments have remained in operation for most of the time since launch, collecting scientific data on the space environment near the spacecraft, the operations of the six remote sensing instruments during the cruise phase are mainly aimed at calibrating the instruments. , and are activated only during dedicated control windows and specific campaigns.

A close pass at the perihelion of the Sun on February 10, 2021 , which brought the spacecraft halfway between the Earth and the Sun, was a unique opportunity that allowed the teams to perform dedicated observations, to control the settings of the tools and much more, to better prepare for the upcoming scientific phase. In full scientific mode, remote sensing and in situ instruments will continuously carry out joint observations.

At the time of passing close to our star, the spacecraft was ‘behind’ the Sun as seen from Earth, which resulted in very low data rates. Therefore, it took a long time to fully download the close passage data, which are still being analyzed.

By a happy coincidence, three of the Solar Orbiter remote sensing instruments have detected a pair of coronal mass ejections (CME, an acronym  coronal mass ejection ) in the days after greater degree of rapprochement. The Extreme Ultraviolet Imager (Eui), Heliospheric Imager (SoloHI) and Coronal Metis devices captured several aspects of the two CMEs that occurred throughout the day.

Infographic of the positions of the space probes that observed the coronal mass ejection (Cme) of 12 February. ESA’s Solar Orbiter was behind the Sun, relative to the Earth. ESA’s Proba-2 – which orbits the Earth – and Esa / Nasa’s Soho – which is in orbit around the Lagrange 1 point, 1.5 million km in front of the Earth towards the Sun – have also seen Cme. Nasa’s Stereo-A glimpsed the event, far from the direct Sun-Earth line. Together, the spacecraft provided valuable and diverse perspectives on the same event. Credits: Esa

The CMEs were also observed by ESA’s Proba-2 satellite and ESA / Nasa’s Soho from the ‘front’ side of the Sun, while NASA’s Stereo-A , located outside the Sun-Earth line, also recorded ‘it a slight glow; all these data allow us to obtain a global vision of the events.

For Solar Orbiter’s SoloHI, this was the first coronal mass ejection seen by the instrument ; Metis had detected one earlier, on January 17, and Eui one in November last year, while the spacecraft’s in situ detectors resumed their first CME  shortly after launch, in April 2020. Many of the in situ instruments also have detected particle activity around the CMEs in February 2021; the data are being analyzed and will be presented shortly.

For SoloHI, the sighting of the Cme took place thanks to a particularly fortunate circumstance, during the telemetry time ‘bonus’. Updates made to ground antennas since mission planning ended have allowed the team to download and link data at times when they would not have expected to be able to, albeit at lower telemetry rates. They therefore decided to collect only the volume of data of a line (the instrument has four sensor lines) at a frequency of two hours, and it happened that in that period of time they managed to capture a Cme.

CMEs are an important part of so-called space weather . The particles trigger auroras on planets with atmospheres, but they can cause malfunctions in some technological devices and can also be harmful to unprotected astronauts. It is therefore important to understand the CMEs and to be able to trace their evolution as they spread throughout the Solar System.

First coronal mass ejection taken by Eui of Solar Orbiter.  Credits: Esa

The study of the CMEs is only one aspect of the Solar Orbiter’s mission. The spacecraft will also send us close observations never made before the Sun and from high solar latitudes, providing us with the first images of our star’s unexplored polar regions . Together with measurements of the solar wind and magnetic field near the spacecraft, the mission will provide new insights into how our star functions in terms of the 11-year cycle of its activity, and how we can better predict periods of space weather storms.«Although the Sun is still at the beginning of its new cycle of activity, Solar Orbiter telescopes – and among them the Coronograph Metis – have already begun to observe the first coronal mass eruptions. In particular, this event is the first detected simultaneously and in temporal succession by the Uv Eui telescope that observes the solar disk and the low corona, the Metis coronograph and the SoloHI heliospheric coronograph, when Solar Orbiter was at a distance of 0.5 astronomical units from the Sole », Silvano Fineschi comments to Media Inaf, Inaf scientific manager for Solar Orbiter. «The Solar Orbiter cruise phase will end on November 27th, after a close encounter with the Earth that will insert the probe into orbit where all the instruments, once the calibration phase is complete, will enter the operational phase. Solar Orbiter will have its first close contact with the Sun next March when it reaches the first perihelion at about 0.3 astronomical units. Metis is the Italian coronographer financed by the Italian Space Agency and operated by the team of scientists from INAF, the University of Florence, Padua and the CNR who have also collaborated with the consortium of Italian industries to develop the instrument ».

To know more:

Watch the ESA video on the Solar Orbiter footage of the coronal mass ejection on YouTube:

Featured image: For Solar Orbiter’s SoloHI, this was the first coronal mass ejection seen by the instrument; Metis had detected one earlier on January 17 and the IUE had detected one in November last year, while the spacecraft’s in-situ detectors resumed their first CME soon after launch in April 2020. Many of the in-situ instruments also detected particle activity around the CMEs in February 2021; the data are being analyzed and will be presented at a later time. Credits: Esa


Provided by INAF

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