Proxima Centauri facts for kids
 False color Hubble Space Telescope WFPC2 image taken in 2013. The bright lines are diffraction spikes. |
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| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) |
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|---|---|
| Constellation | Centaurus |
| Pronunciation | or |
| Right ascension | 14h 29m 42.946s |
| Declination | −62° 40′ 46.16″ |
| Apparent magnitude (V) | 10.43 – 11.11 |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | M5.5Ve |
| Variable type | UV Cet + BY Dra |
| Astrometry | |
| Radial velocity (Rv) | −22.204±0.032 km/s |
| Proper motion (μ) | RA: −3781.741 mas/yr Dec.: 769.465 mas/yr |
| Parallax (π) | 768.0665 ± 0.0499 mas |
| Distance | 4.2465 ± 0.0003 ly (1.30197 ± 8×10−5 pc) |
| Absolute magnitude (MV) | 15.60 |
| Orbit | |
| Primary | Alpha Centauri AB |
| Companion | Proxima Centauri |
| Period (P) | 547,000+6,600 −4,000 yr |
| Semi-major axis (a) | 8,700+700 −400 AU |
| Eccentricity (e) | 0.50+0.08 −0.09 |
| Inclination (i) | 107.6+1.8 −2.0° |
| Longitude of the node (Ω) | 126±5° |
| Periastron epoch (T) | +283+59 −41 |
| Argument of periastron (ω) (secondary) |
72.3+8.7 −6.6° |
| Details | |
| Mass | 0.1221±0.0022 M☉ |
| Radius | 0.1542±0.0045 R☉ |
| Luminosity (bolometric) | 0.001567+0.000020−{{{2}}} L☉ |
| Luminosity (visual, LV) | 0.00005 L☉ |
| Habitable zone inner limit | 0.03731±0.0075 au |
| Habitable zone outer limit | 0.088±0.017 au |
| Surface gravity (log g) | 5.20±0.23 cgs |
| Temperature | 2,992+49 −47 K |
| Metallicity [Fe/H] | 0.21 dex |
| Rotation | 84.9±0.6 days |
| Rotational velocity (v sin i) | < 0.1 km/s |
| Age | 4.85 Gyr |
| Other designations | |
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Alf Cen C, Alpha Centauri C, V645 Centauri, GJ 551, HIP 70890, CCDM J14396-6050C, LFT 1110, LHS 49, LPM 526, LTT 5721, NLTT 37460
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| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| ARICNS | data |
Proxima Centauri is the closest star to Earth after our Sun. It sits about 4.25 light-years away in the southern constellation of Centaurus. A Scottish astronomer named Robert T. A. Innes discovered this star in 1915. Its Latin name means the "nearest star of Centaurus". Proxima Centauri is part of the famous Alpha Centauri star system, where it travels around two bigger stars. Even though it is very close to us, it is far too faint to see with the naked eye. You need a good telescope to spot it in the night sky.
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What Kind of Star Is Proxima Centauri?
Proxima Centauri is a red dwarf, which means it belongs to the main sequence of stars. It is tiny compared to our Sun, with only about one-seventh of the Sun's diameter. That makes it just a bit larger than the planet Jupiter. It is also much cooler and gives off very little visible light. Most of its energy shines out as invisible infrared light. Lower mass stars like this have a very high average density. The surface gravity pulling on its outer layer is more than one hundred times stronger than Earth's gravity.
Because the star has a low mass, heat moves inside it by convection. Hot gas rises up while cooler gas sinks down. This deep churning motion stirs up a powerful magnetic field. Proxima Centauri is known as a flare star. Sometimes, its magnetic field twists and snaps, causing giant stellar flare bursts. These sudden blasts produce strong X-ray light and can quickly make the whole star shine much brighter for several minutes.
Planets Orbiting Proxima Centauri
Astronomers have discovered interesting exoplanet worlds orbiting this small neighbor star. These planets circle Proxima Centauri much closer than the planets in our own solar system circle the Sun.
- Proxima Centauri d: This tiny planet was detected by measuring tiny wobbles in the star's light. It takes just over 5 days to complete one orbit.
- Proxima Centauri b: Found in 2016, this world has about the same mass as our home planet. It completes an orbit in about 11 Earth days.
- Proxima Centauri c: This is a much colder, distant planet candidate that takes around five Earth years to travel around the star.
Could Life Exist Near Proxima Centauri?
Planet b orbits inside what scientists call the habitable zone. This is the special region where temperatures might be just right for liquid water. However, living on this planet would be very difficult. Because it is so close to its star, it might experience tidal locking. This means one side always faces the star in permanent day, while the other side stays in dark night. In addition, the massive stellar flare eruptions throw dangerous radiation across space. These blasts could slowly blow away the atmosphere of any planet that lacks a strong protective magnetic field.
Travel and Future Space Exploration
Because Proxima Centauri is our closest cosmic neighbor, space scientists dream of sending robotic probes there. Reaching it with current chemical rockets would take tens of thousands of years. A famous spacecraft like Voyager 1 would take more than 70,000 years to reach that distance!
To solve this problem, engineers have designed projects like Breakthrough Starshot. This idea uses powerful laser beams on Earth to push tiny, super-light probes through space. These tiny probes could travel at one-fifth the speed of light. At that amazing speed, they could reach Proxima Centauri in about twenty years. When they arrive, they could take close-up pictures of the star and its planets, helping us explore new worlds.
Images for kids
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The bright star Alpha Centauri sits alongside Proxima Centauri in the night sky.
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The long orbital journey that Proxima Centauri takes around Alpha Centauri over thousands of years.
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Sky view showing where to find Proxima Centauri among the southern stars.
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Animation showing how the star seems to shift when viewed by the New Horizons spacecraft.
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A diagram showing the three planets that orbit around Proxima Centauri.
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Comparison of the star's habitable zone with our own solar system.
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Map showing the position of nearby stars within nine light-years from Earth.
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See also
In Spanish: Próxima Centauri para niños
