Content

1. Study of stellar Twins reveal secrets of evolution and future of stars
2. Mission 100% Electrification: Powering the Future of Indian Railways

Study of stellar Twins reveal secrets of evolution and future of stars

Why is it in news?

• A joint team from ARIES (Nainital) and PRL (Ahmedabad) studied four W Ursae Majoris–type (W UMa) contact binary stars using
  • 1.3-m Devasthal Fast Optical Telescope (DFOT) and
  • NASA’s TESS space telescope
• Results were published in the Astrophysical Journal (2026), revealing new evidence on binary star evolution, mass transfer, orbital changes, and magnetic activity.

Relevance

• GS-3 | Science & Technology — Space Research & Astrophysics
  • Advances understanding of stellar evolution, binary mergers, angular-momentum loss
  • Strengthens India’s role in observational astronomy & indigenous research capacity (ARIES–PRL collaboration)
  • Supports precision in exoplanet transit science (better stellar mass–radius calibration)
  • Application to astrophysical modelling, space science innovation, and data-driven research

Basics — What are W Ursae Majoris (W UMa) Stars?

• Type: Short-period contact binary systems
• Orbital period: Typically 0.2–1.0 days (very fast)
• Morphology: Dumbbell-shaped, both stars share a common outer envelope
• Composition: Generally low-mass, main-sequence stars
• Energy sharing: Thermal contact → nearly equal surface temperatures
• Scientific value: Natural laboratories to determine mass, radius, luminosity, temperature, angular momentum loss

Key Findings

• Mass transfer & orbital evolution
  • Evidence of mass exchange between stars
  • Slight orbital period variations → angular-momentum redistribution
• Shared stellar envelope
  • Stars share outer layers, confirming contact-binary energy coupling
• Magnetic activity & star spots
  • Dark star spots cause asymmetric brightness (“lopsided light curves”)
  • Strong magnetic fields + star-spot cycles
  • Spectral emissions confirm flare-linked outer-layer activity
• Improved mass–radius calibration
  • Results refine empirical relations for low-mass stars
  • Critical for stellar structure & evolutionary models

Scientific Significance

• Enhances understanding of:
  • Binary star evolution & merger pathways
  • Angular-momentum loss mechanisms
  • Energy transport in contact binaries
• Supports:
  • Exoplanet transit studies
    (accurate stellar radii = accurate planet sizes)
  • Astrophysical population models
  • Calibration of stellar evolutionary tracks

Conclusion  

• The study of W UMa contact binaries provides high-precision evidence on mass transfer, orbital evolution, and magnetic activity, strengthening models of stellar evolution and merger pathways.
• It enhances India’s scientific capability in space research and improves mass–radius calibration crucial for exoplanet studies and astrophysical modelling.

Mission 100% Electrification: Powering the Future of Indian Railways

 Why is it in news?

• Indian Railways has reached ~99.2% Broad Gauge (BG) electrification as of Nov 2025 (≈ 69,427 RKM electrified out of 70,001 RKM), signalling near-completion of Mission 100% Electrification.
• Electrification pace rose from 1.42 km/day (2004–14) to >15 km/day (2019–25) — a 10× acceleration.
• Solar capacity on the network expanded from 3.68 MW (2014) to 898 MW (Nov 2025), of which 629 MW for traction and 269 MW for non-traction uses.
• India now ranks among the most extensively electrified rail networks globally, comparable to Switzerland (100%), and ahead of China (82%) and Japan (64%).

Relevance

• GS-3 | Infrastructure, Energy & Economy
  • Enhances logistics efficiency, freight competitiveness, operating cost savings
  • Reduces diesel import dependence → strengthens energy security
  • Demonstrates large-scale infrastructure modernisation + mechanised project execution

Basics — What is Railway Electrification? 

• Meaning: Replacing diesel traction with electric traction powered through Overhead Equipment (OHE) and traction substations.
• Traction energy mix: Grid electricity + increasing share of solar and renewable power.
• Operational logic
  • Higher energy efficiency (electric traction ≈ 70% more economical than diesel)
  • Higher haulage capacity & acceleration
  • Lower maintenance + lower dependency on imported fuel
• Environmental logic
  • Reduced GHG emissions, air pollution, noise
  • Enables future migration to green grids / RE integration

Status Snapshot

• Network electrified: 69,427 RKM (≈ 99.2% of BG network)
• Electrified since 2014: 46,900 RKM
• Electrified share over time
  • 2000: 24%
  • 2017: 40%
  • 2024: >96%
  • 2025: ~99.2%

States — Residual Sections (574 RKM pending; 0.8%)

25 States/UTs already 100% electrified.

Global Positioning 

• Switzerland: 100%
• India: ~99%+
• China: 82%
• Spain: 67%
• Japan: 64%
• France: 60%
• Russia: 52%
• UK: 39%

Inference: India is among the world leaders in network-scale electrification.

Solar Power Integration — Data Highlights

• Total solar installed: 898 MW
  • 629 MW (≈70%) — Traction supply
  • 269 MW — Non-traction (stations, workshops, service buildings, housing)
• Stations using solar power: 2,626
• Outcome
  • Reduced grid draw + electricity costs
  • Greater energy security + decarbonisation of traction

Engineering & Technology Interventions

• Cylindrical mechanised foundations (augering)
  • Faster OHE mast installation, less manual excavation, superior consistency
• Automatic Wiring Train
  • Simultaneous catenary + contact wire installation
  • Accurate tensioning → higher safety, faster execution
• Mechanisation + standardisation
  • Shorter project cycles, fewer failures, improved quality

Why Electrification Matters ?

• Economic
  • Lower fuel bill, reduced dependence on diesel imports
  • Higher throughput → freight efficiency & logistics competitiveness
• Environmental
  • Lower emissions; enables shift toward renewable-powered mobility
• Operational
  • Higher speeds, reliability, and network capacity
• Regional development
  • Electrified corridors catalyse industrial & rural connectivity

Conclusion  

• Near-complete railway electrification, backed by rapid pace and large-scale solar integration, marks a major leap in infrastructure modernisation, energy efficiency, and logistics competitiveness.
• It significantly reduces diesel dependence and emissions, positioning Indian Railways as a global leader in sustainable, low-carbon transport transformation.