Our Sun, a blazing sphere of hydrogen and helium, is not just a celestial body; it’s the lifeline of our solar system. Its energy sustains life on Earth, making it the most vital star in our cosmic neighborhood. The Sun’s gravity is the cosmic glue that holds our planetary family together. But, what’s truly remarkable is the Sun’s core, where temperatures soar to an unimaginable 15 million degrees Celsius, facilitating nuclear fusion—the very process that powers this cosmic giant. The Sun’s visible surface, the photosphere, is relatively cooler at about 5,500°C.

Why Study SUN?

The Sun, our nearest star, provides us with a unique opportunity for in-depth study. Its dynamic nature offers insights into not only our Milky Way’s stars but also those in distant galaxies. The Sun, a tempestuous star, occasionally unleashes explosive phenomena that, if directed toward Earth, could disrupt our near-Earth space environment, affecting spacecraft and communication systems. Additionally, astronauts exposed to these events would be in grave danger. The Sun also acts as a natural laboratory, allowing us to study phenomena impossible to replicate on Earth.

The Weather in Space

The Sun’s constant emission of radiation, heat, and high-energy protons, known as the solar wind, fills our solar system. This, coupled with the solar magnetic field, shapes space’s nature. Solar events like Coronal Mass Ejections (CMEs) can disrupt magnetic fields, impacting space assets. This interplay of cosmic forces defines space weather, crucial to our technology-dependent world.

About Aditya L-1

Aditya L-1, India’s premier solar mission, is a space-based observatory focused on the Sun. It will orbit the Sun-Earth L1 point, 1.5 million km from Earth, affording uninterrupted solar observation. Aditya L-1 carries seven payloads to examine the photosphere, chromosphere, and corona using electromagnetic and particle detectors. Four payloads directly observe the Sun, while three conduct in-situ studies of particles and fields.

Aditya L-1 Mission’s Major Objectives

1. Understanding Coronal Heating and Solar Wind Acceleration
2. Studying the Initiation of Coronal Mass Ejections, Flares, and Near-Earth Space Weather
3. Exploring the Coupling and Dynamics of the Solar Atmosphere
4. Analyzing Solar Wind Distribution and Temperature Anisotropy

Uniqueness of the Mission

Aditya L-1 presents several unique features:

• Spatially Resolved Solar Disk Imaging in the Near-UV Band
• Close-up CME Dynamics Observation (~1.05 solar radius)
• On-board Intelligence for Optimized Observations
• Directional and Energy Anisotropy of Solar Wind

Aditya L-1 Science Payload

This mission comprises seven scientific payloads:

1. Visible Emission Line Coronagraph (VELC): Studies the solar corona and dynamics of Coronal Mass Ejections.
2. Solar Ultra-violet Imaging Telescope (SUIT): Images the Solar Photosphere and Chromosphere in near Ultra-violet (UV) and measures solar irradiance variations.
3. Aditya Solar wind Particle EXperiment (ASPEX): Studies solar wind and energetic ions.
4. Plasma Analyser Package for Aditya (PAPA): Analyzes particles and fields in the interplanetary medium.
5. Solar Low Energy X-ray Spectrometer (SoLEXS): Studies X-ray flares from the Sun.
6. High Energy L1 Orbiting X-ray Spectrometer (HEL1OS): Studies X-ray flares over a wide energy range.
7. Magnetometer: Measures interplanetary magnetic fields.

Lagrange Points

Aditya L-1’s unique orbit around the L1 Lagrange point offers exceptional observation advantages. Lagrange points are positions in space where objects tend to stay, making them ideal for space missions. L1 is located between the Sun and Earth, about 1% of the Earth-Sun distance away.

Why Study the Sun from Space?

The Earth’s atmosphere and magnetic field protect us from most solar radiation, making it necessary to study the Sun from space. Understanding solar wind behavior and its interaction with Earth’s magnetic field is vital for space asset management.

Is Aditya L-1 a Complete Solar Mission?

While Aditya L-1 is a groundbreaking mission, it can’t cover all aspects of solar study due to spacecraft limitations. Other Lagrange points, like L5, offer unique perspectives. Additionally, polar regions of the Sun remain relatively unexplored. Aditya L-1 is a crucial step, but more missions are needed to unlock the Sun’s secrets.