Tag: Solar Orbiter

The Sun’s south pole, as seen by Solar Orbiter at perihelion. Click for full movie.

The European Space Agency (ESA) yesterday released a few of the images taken by its Solar Orbiter spacecraft before and during its first perihelion (closest point in its orbit) on March 26, 2022.

The spacecraft was inside the orbit of Mercury, at about one-third the distance from the Sun to the Earth, and its heatshield was reaching around 500°C. But it dissipated that heat with its innovative technology to keep the spacecraft safe and functioning.

Solar Orbiter carries ten science instruments – nine are led by ESA Member States and one by NASA – all working together in close collaboration to provide unprecedented insight into how our local star ‘works’. Some are remote-sensing instruments that look at the Sun, while others are in-situ instruments that monitor the conditions around the spacecraft, enabling scientists to ‘join the dots’ from what they see happening at the Sun, to what Solar Orbiter ‘feels’ at its location in the solar wind millions of kilometres away.

The photo above, cropped, reduced, and revised slightly to post here, looks at the Sun’s south pole, from the side. The surface of the Sun (the top two thirds) almost looks like thunderheads on Earth, except the rain coming from them are high energy heat and radiation.

The data produced a lot of fascinating short movies, all available at the link, including a phenomenon the scientists have nicknamed a “space hedgehog” because of its look. About 15,000 miles across, “At present no one knows exactly what it is or how it formed in the Sun’s atmosphere.”

Click for full image.

The Solar Orbiter science team today released the first images taken during the spacecraft’s first close fly-by of the Sun.

The image to the right, reduced to post here, highlights what they are touting as their first discovery, what they have dubbed “campfires” on the solar surface, small flares previously not known to exist.

The campfires shown in the first image set were captured by the Extreme Ultraviolet Imager (EUI) from Solar Orbiter’s first perihelion, the point in its elliptical orbit closest to the Sun. At that time, the spacecraft was only 77 million km away from the Sun, about half the distance between Earth and the star. “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 the first glance, but when we look in detail, we can see those miniature flares everywhere we look.”

The scientists do not know yet whether the campfires are just tiny versions of big flares, or whether they are driven by different mechanisms. There are, however, already theories that these miniature flares could be contributing to one of the most mysterious phenomena on the Sun, the coronal heating.

Much more to come in future orbits, as the spacecraft works its way even closer to the Sun.

Engineers have now confirmed that Solar Orbiter, having completed its first close fly-by of the Sun, is working perfectly and is producing images and data better than expected.

They will release to the public the first images on July 16.

“The first images are exceeding our expectations,” says Daniel Müller, Solar Orbiter Project Scientist at ESA. “We can already see hints of very interesting phenomena that we have not been able to observe in detail before. The 10 instruments on board Solar Orbiter work beautifully, and together provide a holistic view of the Sun and the solar wind. This makes us confident that Solar Orbiter will help us answer profound open questions about the Sun.”

No other images of the Sun have been taken from such a close distance. During its first perihelion, the point in the spacecraft’s elliptical orbit closest to the Sun, Solar Orbiter got as close as 77 million kilometres from the star’s surface, about half the distance between the Sun and Earth. The spacecraft will eventually make much closer approaches to the Sun. The spacecraft is now in its cruise phase, gradually adjusting its orbit around the Sun. Once in its science phase, which will commence in late 2021, the spacecraft will get as close as 42 million kilometres from the Sun’s surface, closer than the planet Mercury. The spacecraft’s operators will gradually tilt Solar Orbiter’s orbit to enable the probe to get the first proper view of the Sun’s poles.

A previous spacecraft, Ulysses, flew over the Sun’s poles, but it did it from far away, and was designed not to take images but to study the Sun’s solar wind. Solar Orbiter is getting in close.