Know Our Sun : Aditya L1

The First space-based Indian solar mission by the Indian Space & Research Organization (ISRO), “Aditya L1”. Aditya refers to the sun in Sanskrit, and L1 is the location of the satellite (Lagrange point 1), which is approximately 1.5 million km from our planet. The precise locations that Joseph Louis Lagrange, a mathematician, found where the gravitational pulls of the sun and the Earth are balanced are known as Lagrange points. The major advantage of the L1 point is the continuous viewing of the sun without any occultation. On September 2, 2023, at 11:50 IST, the PSLV C57 launched the Aditya-L1 satellite into orbit and recently completed its fourth earthbound manoeuvres successfully. The current orbit is 256 km × 121973 km in dimension. On September 3, 5, and 10, respectively, the first, second, and third earth-bound manoeuvres were successfully executed. The movements are being carried out during the spacecraft's 16-day tour surrounding the Earth, which will provide the spacecraft with the requisite velocity for its subsequent mission to L1. The overall duration of travel from launch to L-1 (Lagrange point) of Aditya L1 would be around four months.

The sun is made up of several layers, comprising the core, convection zone, photosphere, radiative zone, chromosphere, and corona, analogous to our planet. The Sun's energy is all derived from its incredibly dense core, and there is the emission of nuclear energy. Over the core, there is the radiative zone, where light from the core flows. Because of the high density of matter in this area, a photon cannot travel very far without colliding with a particle, which causes it to alter its orientation and drop some of its energy. The solar interior's outermost layer is the convective zone. The convective zone is the solar interior's outermost layer. It is a 200,000-kilometer-thick layer that carries energy from the radiative zone's edge to the surface via massive convection cells, much like a pot of boiling muesli. The plasma in the convective zone's bottom is dangerously heated up, bursts into the outer layer, where it loses heat to space. When the plasma cools, it falls down to the convective zone's bottom.

Hence, the major objectives of the Aditya L1 mission are

1) Investigating the dynamics of the solar outer atmosphere (chromosphere and corona).

2) Monitor the real-time particle and plasma atmosphere that the Sun provides.

3) The heating mechanism of the celestial corona and its physics.

4) Space's atmospheric factors (the origin, structure, and behavior of solar wind).

5) Studies of the solar corona's magnetic field and its topology.

6) The temperature, momentum, and density measurements of coronal and coronal loop plasma.

Overall, Aditya-L1's instruments are set up to observe the solar atmosphere, primarily the chromosphere and corona.

On board Aditya -L1 has a total of seven payloads (Scientific instruments that a satellite carry is known as payload. A satellite may carry a variety of payloads for various space operations.) four of which are engaged in solar remote sensing and three of which are engaged in in-situ solar monitoring. Four Remote sensing payloads are Visible Emission Line Coronagraph(VELC : Corona/Imaging & Spectroscopy), Solar Ultraviolet Imaging Telescope (SUIT : Photosphere and Chromosphere Imaging- Narrow & Broadband), Solar Low Energy X-ray Spectrometer (SoLEXS: Soft X-ray spectrometer), High Energy L1 Orbiting X-ray Spectrometer(HEL1OS : Hard X-ray spectrometer) and the other three are Aditya Solar wind Particle Experiment(ASPEX : Solar wind/Particle Analyzer Protons & Heavier Ions with directions), Plasma Analyser Package For Aditya (PAPA: Electrons and heavier ions from solar wind/Particle Analyzer with directions), Advanced Tri-axial High-Resolution Digital Magnetometers (Magnetic field in real time).

This endeavour is a significant step forward for ISRO and India's space research activities, providing crucial data to our understanding of the Sun and its consequences on our world.