India's Discovery of Circular Polarisation Near a Massive Protostar

By Suryavanshi IAS

---

🌌 Introduction

In a significant achievement for Indian space science, researchers from the Indian Institute of Space Science and Technology (IIST) have detected circular polarisation in radio waves near a massive protostar located approximately 4,500 light years from Earth.

This is the first such discovery of its kind globally and opens a new chapter in understanding star formation and magnetic fields in the cosmos. The findings are published in The Astrophysical Journal Letters, under the title “First Detection of Circular Polarization in Radio Continuum Toward a Massive Protostar.”

---

🌠 What is a Protostar?

A protostar is the earliest stage of a star's formation, when a dense region in a molecular cloud collapses under gravity, accumulating gas and dust.
It is not yet hot enough to initiate nuclear fusion at its core.

📌 The studied protostar: IRAS 18162-2048, located in the Milky Way, is one of the most massive and active known protostars.

---

📡 What is Circular Polarisation?

🔬 Definition:

Circular polarisation occurs when the electric and magnetic fields of an electromagnetic wave (like radio waves) rotate in a circular manner around the wave's direction of travel.

📌 This is rare in natural radio emissions, and its detection gives direct evidence of strong magnetic fields.

---

🧲 What Did the Scientists Discover?

• Circularly polarised radio emission was detected near IRAS 18162-2048.

• Using this, scientists inferred that the magnetic field around the protostar is ~100 times stronger than Earth's.

• This confirms the theory that magnetic fields play a key role in launching powerful stellar jets.

• The results support the idea that magnetically-driven jets from protostars and black holes may share similar formation mechanisms.

---

🕰️ Historical Background

🚀 Star Formation Studies

• Early models of star formation were based mostly on observation and simulations, with limited direct data on magnetic fields.

• Earlier, magnetic fields were inferred indirectly using polarised light or Faraday rotation.

🔭 India's Contributions

• India’s IIST, along with GMRT (Giant Metrewave Radio Telescope), has contributed to several breakthroughs in radio astronomy.

• This detection builds on India’s growing expertise in high-precision astrophysics.

---

📊 Key Data Table

Parameter	Value
Protostar Name	IRAS 18162-2048
Distance from Earth	~4,500 light years
Galaxy	Milky Way
Field Strength near Protostar	~100× Earth’s magnetic field
Telescope Used	Likely GMRT / Global Network (exact not specified)
Journal	The Astrophysical Journal Letters
Key Discovery	Circular polarisation in radio emission

🔍 Why Is This Important?

🔬 Scientific Significance

• First direct measurement of magnetic field strength near a massive protostar.

• Supports theories of magnetically launched stellar jets.

• Connects star and black hole physics under similar magnetic dynamics.

🇮🇳 National Importance

• Enhances India's global stature in space science.

• Demonstrates IIST’s scientific leadership in frontier research.

• Encourages STEM innovation and research funding.

---

🌐 Broader Implications

🧠 Academic Research

• Provides observational proof for long-debated theoretical models.

• Could lead to new simulations of star formation and galaxy evolution.

🔧 Technological Impact

• Improves methods of radio polarimetry and signal processing.

• May have spinoffs in remote sensing, satellite communication, and deep-space navigation.

🔭 Future Space Missions

• Motivates need for more sensitive polarimetric radio telescopes.

• Can inform instruments for upcoming missions like India’s proposed space telescope.

---

Earth vs 🌟 Protostar Magnetic Fields

Aspect	Earth	Massive Protostar (IRAS 18162-2048)
Type of Object	Terrestrial Planet	Massive Protostar (young forming star)
Magnetic Field Strength	~0.5 Gauss (at surface)	~50 Gauss (in immediate surrounding region)
Source of Magnetism	Core dynamo effect	Magnetic fields in gas & dust accreting onto star
Observed By	Ground-based instruments	GMRT & Radio Telescopes (via circular polarisation)
Magnetic Field Role	Protects atmosphere, guides compass	Guides stellar jets, controls mass accumulation
Rotation Effect	Generates auroras, affects satellites	Drives polarised jets, influences star evolution
Variation	Relatively stable, with poles flipping ~200K yrs	Highly dynamic due to rapid gas movement
Relative Strength	1x (baseline)	~100x stronger than Earth's field

🧭 Way Forward

✅ Strengthen Astro-research Institutions

• Enhance support to IIST, IUCAA, PRL, and GMRT.

• Encourage collaborations with global observatories (like ALMA, SKA).

✅ Develop Polarisation-Specific Instruments

• Invest in next-generation polarimetric radio telescopes in India.

• Upgrade existing facilities for better resolution.

✅ Boost Education & Talent

• Launch fellowships for astrophysics at school and college levels.

• Integrate astronomy in school science curriculums under NEP 2020.

✅ International Cooperation

• Collaborate with NASA, ESA, and JAXA on protostar and stellar jet missions.

• Leverage India’s role in SKA (Square Kilometre Array) project.

---

🧠 Important UPSC Keywords

• Protostar

• Circular Polarisation

• Magnetic Fields in Star Formation

• IRAS 18162-2048

• Radio Astronomy

• Astrophysics in India

• Stellar Jets

• IIST Contributions

• GMRT India

• Science & Technology Advancements

---

📝 Mains Practice Questions

GS Paper III (Science and Tech):

"Discuss the significance of detecting circular polarisation near a protostar and its implications for understanding magnetic fields in space."

GS Paper I (Geography – Universe):

"How do magnetic fields influence the formation of stars and stellar jets? Explain in light of recent discoveries."

---

1. Protostar

A protostar is the earliest stage in the formation of a star. It forms when a cloud of gas and dust in space collapses under gravity, beginning nuclear fusion at its core. It is not yet a full-fledged star but continues to gain mass from surrounding matter.

🪐 Relevance: Understanding star formation processes in astronomy and space science.

---

2. Circular Polarisation

Circular polarisation occurs when the electric and magnetic fields of an electromagnetic wave (e.g. radio wave) rotate in a circular manner around the direction of propagation. It is a key indicator of strong magnetic fields in space.

📡 Relevance: Crucial in detecting magnetic fields near celestial bodies like protostars or black holes.

---

3. Magnetic Fields in Star Formation

Magnetic fields play a central role in regulating how stars form, including slowing down the collapse of gas clouds and launching high-speed jets from protostars. Strong magnetic fields also impact the shape and dynamics of stellar nurseries.

🌌 Relevance: Important for understanding the physics behind stellar evolution.

---

4. IRAS 18162-2048

A massive protostar located about 4,500 light years from Earth, within the Milky Way Galaxy. It is now known for being the first site where circularly polarised radio waves have been detected in a star-forming region, indicating intense magnetic activity.

🛰️ Relevance: Advances research on massive star formation and cosmic magnetic fields.

---

5. Radio Astronomy

A branch of astronomy that studies celestial objects using radio waves. Unlike optical telescopes, radio telescopes can detect phenomena hidden in dust clouds, such as forming stars and galaxies.

📶 Institutions: India's GMRT (Giant Metrewave Radio Telescope) is among the world’s most powerful radio observatories.

---

6. Astrophysics in India

Astrophysics is the study of physical properties of celestial bodies. India has made significant strides through institutions like IIST, IIA, IUCAA, and projects like ASTROSAT, GMRT, and Aditya-L1.

🔭 Relevance: Supports India’s space science goals and boosts global scientific cooperation.

---

7. Stellar Jets

High-speed streams of gas and radiation ejected from the poles of protostars or black holes, often aligned with magnetic fields. These jets help stars lose angular momentum and are key to shaping interstellar environments.

🚀 Relevance: Insight into star and planet formation processes, galactic evolution.

---

8. IIST Contributions

The Indian Institute of Space Science and Technology (Thiruvananthapuram) is India’s premier institute for space science education and research. The IIST-led discovery of circular polarisation around a protostar demonstrates India's emerging role in frontier space research.

🎓 Relevance: Strengthens India’s scientific soft power and global credibility.

---

9. GMRT India

The Giant Metrewave Radio Telescope (near Pune) is one of the largest radio telescopes in the world operating at low frequencies. It played a central role in detecting circular polarisation in IRAS 18162-2048, in collaboration with IIST.

📍 Relevance: Critical tool for India’s leadership in global space and radio astronomy.

---

10. Science & Technology Advancements

This refers to India's growing capacity in frontier technologies, including space science, radio astronomy, plasma physics, and astrophysics. The latest discovery adds to this narrative, with implications for global scientific collaboration and national prestige.

🧠 Relevance: Boosts India’s self-reliance and status in emerging technologies (linked to UPSC topics: “Developments in S&T” and “Indigenization”).

🧾 Conclusion

This pioneering detection of circular polarisation near a protostar by Indian scientists is a milestone in space research. It not only enhances global understanding of how massive stars and jets form, but also places India at the forefront of cutting-edge astrophysical discovery. For UPSC aspirants, this is a brilliant example of science meeting constitutional vision—empowering knowledge and international leadership through Indian minds.