Closest Stars

The closest star to Earth is the Sun — our life-giving star and the primary source of light, heat, and energy for our planet. The next closest is Proxima Centauri, but that’s far beyond our solar system. Here are the salient features for each, so you have the full picture:

1. The Sun (Closest Star Overall)

• Distance from Earth: ~149.6 million km (1 Astronomical Unit).
  
  

• Type: G2V main-sequence yellow dwarf star.
  
  

• Diameter: ~1.39 million km (about 109 Earths across).
  
  

• Mass: ~333,000 times Earth’s mass.
  
  

• Temperature:
  Core: ~15 million °C
  Surface (photosphere): ~5,500 °C
  
  

• Age: ~4.6 billion years.
  
  

• Energy Source: Nuclear fusion converting hydrogen into helium, releasing immense energy.
  
  

• Importance for Earth:
  Drives weather and climate.
  Enables photosynthesis, making life possible.
  Influences Earth's magnetic field and auroras through solar wind.
  
  Lifespan: Expected to remain stable for ~5 billion more years before evolving into a red giant.
  
  

2. Proxima Centauri (Closest Star Beyond the Sun)

• Distance from Earth: ~4.24 light-years (~40 trillion km).
  
  

• Type: M5.5Ve red dwarf star.
  
  

• Diameter: ~14% of the Sun’s.
  
  

• Mass: ~12% of the Sun’s.
  
  

• Temperature: ~3,050 °C (cooler than the Sun).
  
  

• Age: Estimated 4–5 billion years.
  
  

• Special Features:
  Part of the Alpha Centauri triple star system.
  Has at least two confirmed exoplanets: Proxima b (in the habitable zone) and Proxima d.
  Frequently emits intense stellar flares, which may make its planets less hospitable for life.
  
  

• Visibility: Too faint to see with the naked eye from Earth