Description

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Context

Scientists at the Indian Institute of Astrophysics (IIA) Bengaluru have reported the “first significant” results from the Visible Emission Line Coronagraph (VELC) payload onboard the ADITYA-L1.

Read about Aditya 1: https://www.iasgyan.in/daily-current-affairs/aditya-l-1-launched

About IIA

The Indian Institute of Astrophysics (IIA), with its headquarters in Bengaluru, is an autonomous research institute wholly funded by the Department of Science and Technology, Government of India. It was established in 1971. IIA conducts research primarily in the areas of astronomy, astrophysics and related fields.

The institute has a network of laboratories and observatories in India, including the Kodaikanal Solar Observatory, Kavalur (the Vainu Bappu Observatory), the Gauribidanur Radio Observatory, Hanle (the Indian Astronomical Observatory) and Hosakote.

Details

Scientists have used a special tool on the spacecraft, called the Visible Emission Line Coronagraph (VELC), to capture the early stages of a massive solar eruption, known as a coronal mass ejection (CME), which occurred on July 16, 2024.

Read about CME: https://www.iasgyan.in/daily-current-affairs/coronal-mass-ejections-cmes#:~:text=CMEs%20are%20typically%20caused%20by,they%20frequently%20occur%20in%20tandem.

This is the first significant scientific result from Aditya-L1, which was launched by the Indian Space Research Organisation (ISRO) on September 2, 2023, to study the Sun.

The VELC instrument, developed by the Indian Institute of Astrophysics (IIA) in Bengaluru along with ISRO, is designed to closely observe the outer layer of the Sun, called the corona.

Read about corona and layers of sun: https://www.iasgyan.in/daily-current-affairs/solar-corona

This tool is stationed at a special point in space, called L1, where it can constantly monitor the Sun without any interference from Earth.

Read about Lagrange points :

https://www.iasgyan.in/daily-current-affairs/lagrange-points-38#:~:text=Lagrange%20points%2C%20also%20known%20as,Sun%2C%20create%20a%20stable%20equilibrium.&text=There%20are%20five%20Lagrange%20points,with%20unique%20characteristics%20and%20properties.

VELC lets scientists see CMEs when they are still close to the Sun’s surface, which wasn’t possible with earlier instruments. These early observations give scientists important information on how CMEs form and develop, helping them improve predictions about space weather.

As the Sun approaches the most active phase of its 11-year solar cycle, CMEs are expected to happen more frequently.

What is a coronagraph?

A coronagraph is a specialized instrument designed to block out the light of the sun so that researchers can glimpse the burning star's hot, thin, outermost layer, called the corona.

The French astronomer Bernard Lyot invented the coronagraph in the 1930s.

The sun's corona is normally visible only during solar eclipses, when the moon's shadow covers the bright central layers of our parent star and allows its dimmer corona to appear. A coronagraph mimics this natural phenomenon with a circular mask that sits inside a telescope and selectively blocks the bulk of the sun's light.

Examples of coronagraphs

Topic	Details
Keck Telescope Observations	The Keck telescope on Mauna Kea in Hawaii uses a coronagraph to block starlight and observe baby planets forming within protoplanetary disks of gas and dust around young stars. This helps in studying the structure and composition of disks, advancing knowledge of planetary formation.
Starshade Technology	A starshade is an external, flower-like filter that floats in space between a telescope and the target star. Unlike a coronagraph, it blocks starlight outside the telescope, reducing glare and allowing telescopes to image faint exoplanets more clearly. NASA plans to pair a starshade with the Nancy Grace Roman Space Telescope for enhanced exoplanet imaging.
Traditional Coronagraphs	Traditional coronagraphs remain important for solar research. NASA's STEREO-A spacecraft, orbiting between Earth and Venus, uses a coronagraph to monitor the sun's corona and capture details of solar phenomena like flares, streamers, and coronal mass ejections. This helps improve understanding of space weather's effects on Earth.