Science & Technology

IIA study reveals thermal evolution of interplanetary coronal mass ejections

By TestNeeti Editorial TeamPublished Thursday, 2 July 2026 2 min readSource: GKTodayArticle 11 of 21

Interplanetary Coronal Mass Ejections (ICMEs) are large solar eruptions that travel from the Sun to Earth and interact with the solar wind and geomagnetic field. A long-term statistical study by the Indian Institute of Astrophysics (IIA), Bengaluru, examined ICME thermal behaviour at 1 Astronomical Unit (AU) using observations from 1995 to 2024, spanning Solar Cycles 23, 24 and the rising phase of 25. The study found that nearly 45% of magnetic ejecta showed heating signatures at 1 AU, especially near solar maximum, challenging earlier assumptions that ICMEs only cool during expansion. It also recorded a shift from more heating-like states in Solar Cycle 23 to more cooling-dominated states in Solar Cycle 24. The investigation was led by Soumyaranjan Khuntia and Wageesh Mishra, and published in Monthly Notices of the Royal Astronomical Society by 1 July 2026.

Key Facts & Details

9 points

1
Interplanetary Coronal Mass Ejections (ICMEs) are large solar eruptions travelling from the Sun to Earth, interacting with the solar wind and geomagnetic field.
2
A study by the Indian Institute of Astrophysics (IIA), Bengaluru, examined ICME thermal behaviour at 1 Astronomical Unit (AU) using 1995-2024 observations.
3
The dataset spanned Solar Cycles 23, 24 and the rising phase of 25.
4
Nearly 45% of magnetic ejecta showed heating signatures at 1 AU, especially near solar maximum, challenging the assumption that ICMEs only cool during expansion.
5
The study recorded a shift from more heating-like states in Solar Cycle 23 to more cooling-dominated states in Solar Cycle 24.
6
It was led by Soumyaranjan Khuntia and Wageesh Mishra and published in Monthly Notices of the Royal Astronomical Society.

Deep Dive

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ICME thermal state is linked with the disturbance potential of solar storms, which can affect radio communications, aviation, satellites, GPS and power grids.
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1 Astronomical Unit is the mean Earth-Sun distance, about 149.6 million kilometres.
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Coronal mass ejections are among the main drivers of geomagnetic storms on Earth; Solar Cycle 23 began in 1996, Cycle 24 in 2008, and Cycle 25 is current.

Exam Focus

Examiners may ask which institute led the ICME study (IIA Bengaluru), the value of 1 AU, or which solar cycles the 29-year dataset covered.

Exam Relevance & Angle

Understanding ICME thermal evolution improves space-weather forecasting, which protects satellites, power grids, aviation and communications. The IIA study, using a 29-year dataset, refines models of how solar storms behave as they approach Earth at 1 AU.

Target Exams

UPSC CSESSC CGLRRB NTPCState PCS

Background & Context

Coronal mass ejections (CMEs) are massive expulsions of plasma and magnetic field from the Sun's corona; their interplanetary counterparts, ICMEs, travel through space and can trigger geomagnetic storms on reaching Earth. Measurements are commonly made at 1 Astronomical Unit (AU), the average Earth-Sun distance of about 149.6 million km, where spacecraft record plasma properties. The solar cycle is roughly 11 years long, and studying ICME thermodynamics across multiple cycles helps forecast space weather. The Indian Institute of Astrophysics in Bengaluru is a premier autonomous research institute in astronomy and astrophysics.