Proxima Centauri
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Coordinates: 14h 29m 42.9487s, -62° 40' 46.141?
Proxima Centauri
Proxima Centauri as seen by Hubble
Observation data
Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation
Centaurus
Pronunciation
/'pr?ks?m? s?n't?ri?/
Right ascension
14h 29m 42.9487s
Declination
-62° 40' 46.141?
Apparent magnitude (V)
11.05
Characteristics
Spectral type
M5.5 Ve
Apparent magnitude (J)
5.35 ± 0.02
U-B color index
1.43
B-V color index
1.90
Variable type
Flare star
Astrometry
Radial velocity (Rv)
-21.7 ± 1.8 km/s
Proper motion (µ)
RA: -3775.40 mas/yr
Dec.: 769.33 mas/yr
Parallax (p)
768.7 ± 0.3 mas
Distance
4.243 ± 0.002 ly
(1.3009 ± 0.0005 pc)
Absolute magnitude (MV)
15.49
Details
Mass
0.123 ± 0.006 M?
Radius
0.141 ± 0.007 R?
Luminosity (bolometric)
0.0017 L?
Surface gravity (log g)
5.20 ± 0.23 cgs
Temperature
3,042 ± 117 K
Metallicity
0.21 dex
Rotation
83.5 days
Rotational velocity (v sin i)
2.7 ± 0.3 km/s
Age
4.85 Gyr
Other designations
Database references
SIMBAD
data
Proxima Centauri (Latin proxima, meaning "next to" or "nearest to") is a red dwarf about 4.24 light-years from the Sun, inside the G-cloud, in the constellation of Centaurus. It was discovered in 1915 by the Scottish astronomer Robert Innes, the Director of the Union Observatory in South Africa, and is the nearest known star to the Sun, although it is too faint to be seen with the naked eye, with an apparent magnitude of 11.05. Its distance to the second- and third-nearest stars, which form the bright binary Alpha Centauri, is 0.237 ± 0.011 ly (15,000 ± 700 AU). Proxima Centauri is very likely part of a triple star system with Alpha Centauri A and B, but its orbital period may be greater than 500,000 years.Because of Proxima Centauri's proximity, its distance from Earth and angular diameter can be measured directly, from which it can be determined that its diameter is about one-seventh of that of the Sun. Proxima Centauri's mass is about an eighth of the Sun's (M?), and its average density is about 40 times that of the Sun. Although it has a very low average luminosity, Proxima is a flare star that undergoes random dramatic increases in brightness because of magnetic activity. The star's magnetic field is created by convection throughout the stellar body, and the resulting flare activity generates a total X-ray emission similar to that produced by the Sun. The mixing of the fuel at Proxima Centauri's core through convection and its relatively low energy-production rate mean that it will be a main-sequence star for another four trillion years, or nearly 300 times the current age of the universe.Searches for companions orbiting Proxima Centauri have been unsuccessful, ruling out the presence of brown dwarfs and supermassive planets. Precision radial velocity surveys have also ruled out the presence of super-Earths within the star's habitable zone. The detection of smaller objects will require the use of new instruments, such as the James Webb Space Telescope, which is scheduled for deployment in 2018. Because Proxima Centauri is a red dwarf and a flare star, whether a planet orbiting it could support life is disputed. Nevertheless, because of the star's proximity to Earth, it has been proposed as a destination for interstellar travel.
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^ Christian, D. J.; Mathioudakis, M.; Bloomfield, D. S.; Dupuis, J.; Keenan, F. P. (2004). "A Detailed Study of Opacity in the Upper Atmosphere of Proxima Centauri". The Astrophysical Journal 612 (2): 1140–1146. Bibcode:2004ApJ...612.1140C. doi:10.1086/422803.
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^ Gilster, Paul (2004). Centauri Dreams: Imagining and Planning. Springer. ISBN 0-387-00436-X.
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