Proxima Centauri

Proxima Centauri is the nearest star to Earth after the <a href="/facts/Sun/CadPCVHh">Sun</a>, located 4.25 <a href="/facts/Light-year/IGc5NdQb">light-years</a> away in the southern <a href="/facts/Constellation/nBQqgW8A">constellation</a> of <a href="/facts/Centaurus/NQEDC6xA">Centaurus</a>. This object was discovered in 1915 by <a href="/facts/Robert_T._A._Innes/VUE31BDr">Robert Innes</a>. It is a small, low-mass <a href="/facts/Star/PFbd6ICx">star</a>, too faint to be seen with the <a href="/facts/Naked_eye/ePEIa0lK">naked eye</a>, with an <a href="/facts/Apparent_magnitude/7pCTF1Me">apparent magnitude</a> of 11.13. Its <a href="/facts/Latin_language/pM3Kge85">Latin</a> name means the 'nearest [star] of Centaurus'. Proxima Centauri is a member of the <a href="/facts/Alpha_Centauri/6BlySfIj">Alpha Centauri</a> <a href="/facts/Star_system/1vX99BMV">star system</a>, being identified as component Alpha Centauri C, and is 2.18° to the southwest of the Alpha Centauri AB pair. It is currently 12,950 <a href="/facts/Astronomical_unit/gjsbu5xU">AU</a> (0.2 <a href="/facts/Light-year/IGc5NdQb">ly</a>) from AB, which it orbits with a <a href="/facts/Orbital_period/94f56uh2">period</a> of about 550,000 years.
Proxima Centauri is a <a href="/facts/Red_dwarf/56CMQcF0">red dwarf</a> star with a mass about 12.5% of the Sun's mass (<a href="/facts/Solar_mass/j6Auhku8">M☉</a>), and average <a href="/facts/Density/92p6hh9I">density</a> about 33 times that of the Sun. Because of Proxima Centauri's proximity to <a href="/facts/Earth/HLLmDfj0">Earth</a>, its <a href="/facts/Angular_diameter/p2xv4vcQ">angular diameter</a> can be measured directly. Its actual diameter is about one-seventh (14%) the diameter of the Sun. Although it has a very low average <a href="/facts/Luminosity/1tdhpk9l">luminosity</a>, Proxima Centauri is a <a href="/facts/Flare_star/lGqncdn8">flare star</a> that randomly undergoes dramatic increases in brightness because of <a href="/facts/Magnetic_activity/TEsF7BxY">magnetic activity</a>. The star's <a href="/facts/Magnetic_field/Ta8Ev588">magnetic field</a> is created by <a href="/facts/Convection/E8vsCPhu">convection</a> throughout the stellar body, and the resulting flare activity generates a total <a href="/facts/X-ray/wseP79cN">X-ray</a> emission similar to that produced by the Sun. The internal mixing of its fuel by convection through its core and Proxima's relatively low energy-production rate, mean that it will be a <a href="/facts/Main-sequence_star/DJ3Wq8kd">main-sequence star</a> for another four trillion years.
Proxima Centauri has one known <a href="/facts/Exoplanet/zjfmqfUf">exoplanet</a> and two candidate exoplanets: <a href="/facts/Proxima_Centauri_b/k6nG5yrG">Proxima Centauri b</a>, the candidate <a href="/facts/Proxima_Centauri_d/6vSeytbA">Proxima Centauri d</a> and the disputed <a href="/facts/Proxima_Centauri_c/TzY7AhfK">Proxima Centauri c</a>. Proxima Centauri b orbits the star at a distance of roughly 0.05 AU (7.5 million km) with an orbital period of approximately 11.2 Earth days. Its estimated mass is at least 1.07 times that of Earth. Proxima b orbits within Proxima Centauri's <a href="/facts/Habitable_zone/bjgaUkfB">habitable zone</a>—the range where temperatures are right for liquid water to exist on its surface—but, because Proxima Centauri is a red dwarf and a flare star, the planet's <a href="/facts/Habitability_of_red_dwarf_systems/Bp2gPkR0">habitability</a> is highly uncertain. A candidate <a href="/facts/Super-Earth/C8xrtn2w">super-Earth</a>, <a href="/facts/Proxima_Centauri_c/TzY7AhfK">Proxima Centauri c</a>, roughly 1.5 AU (220 million km) away from Proxima Centauri, orbits it every 1,900 d (5.2 yr). A candidate <a href="/facts/Sub-Earth/WgQeubqw">sub-Earth</a>, <a href="/facts/Proxima_Centauri_d/6vSeytbA">Proxima Centauri d</a>, roughly 0.029 AU (4.3 million km) away, orbits it every 5.1 days.

Proxima Centauri open-in-new

Proxima Centauri