SYLLABUS

GS-3: Awareness in the fields of IT, Space, Computers, robotics, nano-technology, bio-technology and issues relating to intellectual property rights. 

Context: 

Scientists at the Indian Institute of Astrophysics, working with NASA, used the Visible Emission Line Coronagraph (VELC) payload on India’s Aditya-L1 solar observatory to precisely measure key parameters of a coronal mass ejection (CME) near its point of eruption.

Key Findings

First-of-its-kind Observations: 

• VELC has recorded the first-ever spectroscopic observations of a Coronal Mass Ejection (CME) in the visible wavelength range, closest to the Sun's visible surface.
• It provides a sustained view of the Sun for 24 hours everyday because of being at the Sun-Earth Lagrangian L1 location, where the Sun never sets.

Key Physical Parameters Measured: 

• Electron density of the CME was about 370 million electrons/cm³, far higher than the 10–100 million typical of non-CME coronal regions. CME energy release was estimated at 9.4×10²¹ joules, several orders of magnitude greater than the energy of World War II atomic bombs.
• CME mass was nearly 270 million tonnes, vastly larger than the 1.5 million-tonne iceberg that sank the Titanic.
• Initial velocity measured at 264 km/s, and temperature estimated at 1.8 million Kelvin.

Future Prospects: With Solar Cycle 25 nearing its peak and VELC fully operational, even larger and more energetic eruptions are expected to be observed and studied in the coming months.

About Aditya-L1 Mission 

Aditya-L1 was launched by the Indian Space Research Organisation (ISRO) on September 2, 2023, with the mission of observing and better understanding the Sun.

The mission aims to observe the Sun’s corona and understand its extreme heat from a halo orbit around the first Sun-Earth Lagrangian point (L1), which is located roughly 1.5 million km from the Earth.

• Aditya-L1 is India's first space-based solar mission to operate outside Earth's orbit. 

Aditya-L1 has seven instruments for the observation of all the radiation and charged particles such as:

• Visible Emission Line Coronagraph (VELC)
• Solar Ultra-Violet Imaging Telescope (SUIT) payload
• Aditya Solar wind Particle Experiment (ASPEX)
• Plasma Analyser Package for Aditya (PAPA) payloads
• Solar Low Energy X-ray Spectrometer (SoLEXS) 
• High Energy L1 Orbiting X-ray Spectrometer (HEL1OS)
• Advanced Tri-axial High Resolution Digital Magnetometers 

Visible Emission Line Coronagraph (VELC) Payload

VELC is developed by the Indian Institute of Astrophysics at their CREST campus in Karnataka.

It is an internally occulted solar coronagraph equipped for simultaneous imaging, spectroscopy, and spectro-polarimetry near the solar limb.

VELC images the solar corona starting from 1.05 solar radii, the closest ever by any such instrument, offering insights into coronal structure and dynamics.

Scientific Objectives: 

• VELC facilitates detailed analysis of the solar corona’s temperature, plasma velocity, electron density, and magnetic field parameters.
• It focuses on understanding the initiation and evolution of CMEs and their impact on space weather.
• These observations enhance knowledge of coronal heating, solar wind acceleration, and the Sun’s magnetic field dynamics.

Advantages of VELC payload: 

• It offers uninterrupted 24×7 solar viewing from the Sun–Earth L1 point, where the Sun never sets.
• Near-Sun data from VELC are crucial for quantifying the actual mass and energy lost during CME eruptions, unlike previous observations from larger distances.
• These first-of-its-kind near-Sun spectroscopic observations are essential for improving the understanding of CME properties and their impacts. 

Sources:
The Hindu
Isro. Gov