Proxima Centauri b

Proxima Centauri b is a terrestrial exoplanet orbiting the red dwarf star Proxima Centauri, the closest star to our Sun. Located in the constellation Centaurus, it sits just 4.2 light-years from Earth—making it the nearest known exoplanet in the galaxy.

Orbital & Physical Characteristics

• 🪐 Type: Super-Earth (rocky)

• 📏 Orbital Distance: ~0.0485 AU (very close to its star)

• 🔄 Orbital Period: ~11.2 Earth days

• ⚖️ Mass: ~1.07 Earth masses

• 📐 Radius: Estimated between 0.94–1.4 Earth radii

• 🌡️ Temperature: Equilibrium temp ~234 K (−39 °C / −38 °F)

Habitable Zone Potential Proxima Centauri b orbits within its star’s habitable zone, where conditions might allow for liquid water. It receives a similar amount of stellar energy as Earth does from the Sun. However, its habitability is uncertain due to intense stellar activity.

Atmospheric Unknowns

• 🌬️ Atmosphere: Unknown. If it exists, it may be thin or stripped by stellar flares.

• ☢️ Stellar Activity: Proxima Centauri is a flare star, emitting bursts of radiation that could erode any atmosphere and affect surface conditions.

Discovery & Significance

• 🔭 Discovered: August 24, 2016, by the European Southern Observatory

• 📡 Method: Doppler spectroscopy (radial velocity)

• 🌌 Why It Matters: It’s the closest exoplanet to Earth and a prime candidate for future robotic exploration. Projects like Breakthrough Starshot aim to send probes to the Alpha Centauri system, with Proxima b as a key target.