Polarimeter to Unify the Corona and Heliosphere

Polarimeter to Unify the Corona and Heliosphere (PUNCH): A Journey into the Sun’s Enigma

Imagine peering through a telescope not just at the sun, but into its very essence—its corona and heliosphere. That’s exactly what NASA’s upcoming mission, Polarimeter to Unify the Corona and Heliosphere (PUNCH), aims to do. This ambitious project, also known as SMEX-15, is set to launch in 2025 with a budget of $165 million, including launch costs.

Understanding the Sun’s Enigma

The sun, our closest star and the heart of our solar system, has always been a mystery wrapped in an enigma. The corona, the outermost layer of the sun’s atmosphere, is one of its most intriguing features. It’s here that the transition from the hot, dense plasma of the corona to the cooler, less dense solar wind occurs. But how does this happen? PUNCH aims to unravel these mysteries by studying the unexplored region from the middle of the solar corona out to 1 AU (Astronomical Unit) from the sun.

Four Microsatellites for a Comprehensive View

To achieve its goals, PUNCH will consist of four microsatellites. Each satellite carries one primary instrument: the Narrow Field Imager, Wide Field Imagers, Student Thermal Energetic Activity Monitor (STEAM), and other instruments. These satellites work together as a constellation to observe the corona and heliosphere as elements of a single system through continuous 3D deep-field imaging.

Key Objectives

The primary objective is to understand how the solar corona becomes the solar wind, with specific objectives including understanding coronal structures and transient solar wind structures. By studying these phenomena, PUNCH hopes to improve our understanding of space weather events like coronal mass ejections (CMEs) and mitigate their effects on Earth’s systems.

Observing the Sun in Polarized Light

To achieve its goals, PUNCH will use polarimetry. This technique involves observing the sun in polarized light to study the physics of coronal heating and solar flares. The mission aims to acquire polarized white-light images over a composite 90° field of view centered on the Sun.

Removing Point Spread Function Effects

Data from PUNCH will undergo pipeline processing to remove point spread function effects, ensuring that minor photometric errors due to compression are tracked and eliminated. This process is crucial for maintaining the accuracy and reliability of the mission’s findings.

A Novel Approach to Background Subtraction

The polarimetry of the K-corona (the region between the sun and Earth) is affected by starfield polarization, which requires a novel formalism for background subtraction while preserving linear polarimetry. This innovative approach ensures that PUNCH can provide accurate and detailed images of the solar corona.

Public Access to Data

The primary product images produced on 4-minute cadence will be available to everyone via NASA’s SDAC facility and Virtual Solar Observatory, ensuring that the findings from this mission are accessible to researchers and enthusiasts alike.

Collaboration for Success

PUNCH is a collaborative effort involving SwRI (Space Science Institute), NRL (Naval Research Laboratory), and Rutherford Appleton Laboratory. The mission will operate in low Earth orbit, working in synergy with Parker Solar Probe and ESA’s Solar Orbiter to provide a comprehensive view of the sun and its effects on our solar system.

Conclusion

Polarimeter to Unify the Corona and Heliosphere (PUNCH) is more than just a mission; it’s a step towards understanding one of nature’s most powerful phenomena. By studying the transition from the corona to the solar wind, PUNCH aims to unlock secrets that could help us better predict and mitigate space weather events. As we launch into this exciting journey, let’s hope that PUNCH will bring us closer to unraveling the mysteries of our sun and its impact on Earth.