8 pictures you must see to understand what ISRO's Aditya L1 is looking for

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The Sun’s outermost layer, the corona burns at nearly 6,000 degrees Kelvin — that’s hotter than the disk underneath. And, ISRO wants to find out why.

Scientists think it might be because the process is magnetic — akin to solar ‘tornadoes’.

“How the corona gets heated to such high temperatures is still an unanswered question in solar physics,” it says.

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The Visible Emission Line Chronograph (VELC) is the largest instrument aboard abroad the Aditya L1 satellite. It’s objective is to study the corona, including the origin of coronal mass ejections (CMEs) — a sudden and significant release of plasma and magnetic field.

They often occur just after solar flares — tongues of fire that reach out thousands of kilometres above the sun’s surface. VELC will be able to observe the plasma as it’s released into the solar wind.

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X-rays are why we know that solar corona is hotter than the rest of the Sun. Only very hot gases, like the corona, have the ability to emit X-rays. The Solar Low Energy X-ray Spectrometer (SoLEXS) and the High Energy L1 Orbiting X-ray Spectrometer (HEL1OS) are two instruments aboard Aditya L1 to study those X-rays.

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Solar storms are believed to be at the epicentre of space weather. And, Aditya L1 plans to keep a close eye of these storms using the Plasma Analyser Package for Aditya (PAPA), Aditya Solar Wind Particle Experiment (ASPEX) and Magnetometer.

Observational data from those instruments will help astronomers understand more about the origin and evolution of these storms.

On Earth, humans are protected from the Sun’s radiation by the planet’s atmosphere. But, in outer space, strong radiation and solar particles can be deadly to spacecraft and astronauts. Analysing the path of solar storms could help dictate future predictions reducing the risks of space exploration.

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The Aditya 1 mission was originally conceived to only study the corona — the Sun’s outermost layer. With time, ISRO repurposed the mission and now it will also be collecting information about the solar photosphere and chromosphere while monitoring solar winds and magnetic fields.

These two layers are still above the surface, but below the corona — and not as hot.

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The photosphere is the lowest layer and around 500 kilometres thick. This is where the Sun’s energy is released as light.

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The photosphere, on the other hand, is where the Sun’s magnetic field breaks through the surface. It can be observed by detecting the ‘sunspots’ over the sun’s disk. The movement of the sunspots is what led scientists to discover that the Sun’s isn’t stagnant — it actually rotates.

The photosphere is also where solar flares originate.

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The Aditya L1 mission, unlike the Parker Solar Probe, won’t actually go anywhere near the Sun. However, unlike other satellites, it’s not going to be stuck in Earth’s lower atmosphere either.

Instead, the plan is to launch it in a halo orbit around Lagrangian Point 1 (L1), which is approximately 1.5 kilometres from the Earth’s surface. At L1, the ISRO satellite will still be moving in orbit but its position relative to the Sun and the Earth will be stable.

"A satellite placed in the halo orbit around L1 of the Sun-Earth system has the major advantage of continuously viewing the Sun without any occultation or eclipses," says ISRO.

See also:

NASA’s Sun probe sheds new light on our star — here are 5 new secrets it uncovered