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Proxima Centauri

Proxima Centauri (not shown) is near Toliman (α Centauri) in lower portion of this diagram.
Observation data
Epoch J2000
Constellation
(pronunciation)		Centaurus
Right ascension14h 29m 42. In Astronomy, an epoch is a moment in time used as a reference for the Orbital elements of a Celestial body. In common usage a constellation is a group of celestial bodies that are connected together in some arrangement typically stars to form a visible figure or picture Each culture has its own Constellations usually based on Mythology. Centaurus ( Centaur) is a bright constellation of the southern hemisphere. Right ascension (abbrev RA; symbol α) is the Astronomical term for one of the two Coordinates of a point on the Celestial sphere 9487s[1]
Declination−62° 40′ 46. In Astronomy, declination (abbrev dec or δ) is one of the two coordinates of the Equatorial coordinate system, the other being either 141″[1]
Apparent magnitude (V)11. The apparent magnitude ( m) of a celestial body is a measure of its Brightness as seen by an observer on Earth, normalized to the value 05[1]
Characteristics
Spectral typeM5. In Astronomy, stellar classification is a classification of Stars based initially on photospheric temperature and its associated Spectral characteristics 5 Ve[1]
U-B color index1. In Astronomy, the color index is a simple numerical expression that determines the color of an object which in the case of a Star gives its Temperature 49[1]
B-V color index1. In Astronomy, the color index is a simple numerical expression that determines the color of an object which in the case of a Star gives its Temperature 90[1]
Variable typeFlare star
Astrometry
Radial velocity (Rv)−21. For the astronomical object see Variable star. Variable Star is a 2006 novel written by Spider Robinson A flare star is a Variable star which can undergo unpredictable dramatic increases in brightness for a few minutes Astrometry is the branch of Astronomy that relates to precise measurements and explanations of the positions and movements of Stars and other celestial bodies Radial velocity is the Velocity of an object in the direction of the line of sight (i 7[2] km/s
Proper motion (μ)RA: -3775. The proper motion of a Star is the measurement of its change in position in the sky over time after Improper motions are accounted for 64[1] mas/yr
Dec. A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60 of one degree. A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun : 768. 16[1] mas/yr
Parallax (π)771. A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60 of one degree. A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun Parallax is an apparent displacement or difference of orientation of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between 99 ± 2. 25[1] mas
Distance4. A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60 of one degree. Distance is a numerical description of how far apart objects are 22 ± 0. 01 ly
(1. A light-year or light year (symbol ly) is a unit of Length, equal to just under ten trillion Kilometres As defined by 295 ± 0. 004 pc)
Absolute magnitude (MV)15. History The first direct measurements of an object at interstellar distances were undertaken by German Astronomer Friedrich Wilhelm Bessel in 1838 In Astronomy, absolute magnitude (also known as absolute visual magnitude) is the Apparent magnitude an object would have if it were at a standard 49
Details
Mass0. Mass is a fundamental concept in Physics, roughly corresponding to the Intuitive idea of how much Matter there is in an object 123[3] M☉
Radius0. The solar mass is a standard way to express Mass in Astronomy, used to describe the masses of other Stars and galaxies. Remote Authentication Dial In User Service ( RADIUS) is a networking protocol that provides centralized access authorization and accounting management for people or computers 145[3] R☉
Surface gravity (log g)5. In Astronomy, the solar radius is a unit of Length used to express the size of Stars It is equal to the current radius of the Sun. The surface gravity, g, of an astronomical or other object is the Gravitational acceleration experienced at its surface 20[4]
Luminosity1. Luminosity has different meanings in several different fields of science 38 × 10−4[3] L☉
Temperature3,040[3] K
Rotation83. The solar luminosity, L_\odot is a unit of Luminosity ( power emitted in the form of Photons conventionally used by Astronomers to Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic Stellar rotation is the angular motion of a Star about its axis 5 days[5]
Age4. A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth 85 × 109[3] years
Other designations
α Centauri C, V645 Centauri, GCTP 3278.00, GJ 551, LHS 49, LFT 1110, LTT 5721, HIP 70890. A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun A star catalogue, or star catalog, is an Astronomical catalogue that lists Stars In Astronomy, many stars are referred to simply by catalogue For the astronomical object see Variable star. Variable Star is a 2006 novel written by Spider Robinson A star catalogue, or star catalog, is an Astronomical catalogue that lists Stars In Astronomy, many stars are referred to simply by catalogue Wilhelm Gliese ( June 21 1915 &ndash June 12 1993) was a German astronomer A star catalogue, or star catalog, is an Astronomical catalogue that lists Stars In Astronomy, many stars are referred to simply by catalogue A star catalogue, or star catalog, is an Astronomical catalogue that lists Stars In Astronomy, many stars are referred to simply by catalogue A star catalogue, or star catalog, is an Astronomical catalogue that lists Stars In Astronomy, many stars are referred to simply by catalogue The Hipparcos and Tycho Catalogues (Tycho-1 are the primary products of the European Space Agency 's astrometric mission Hipparcos. [1]

Proxima Centauri (Latin proximus, -a, -um: meaning 'next to' or 'nearest to')[6] is a red dwarf star that is likely a part of the Alpha Centauri star system and is the nearest star to the Sun at a distance of 4. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool Star, of the Main sequence, either late K A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth Alpha Centauri (α Centauri / α Cen also known as Rigil Kentaurus, Rigil Kent, or Toliman, is the brightest Star in the southern Constellation This list of stars nearest to the Earth is ordered by increasing distance out to a maximum of 5 Parsecs (16 The Sun (Sol is the Star at the center of the Solar System. 22 light-years. A light-year or light year (symbol ly) is a unit of Length, equal to just under ten trillion Kilometres As defined by [7] As the name suggests, it is located in the constellation of Centaurus. Centaurus ( Centaur) is a bright constellation of the southern hemisphere.

Proxima Centauri is categorized as a flare star, as it undergoes random increases in luminosity because of magnetic activity. A flare star is a Variable star which can undergo unpredictable dramatic increases in brightness for a few minutes It only has about an eighth of the Sun's mass, and consequently it has a very low luminosity. Because of its proximity, the size of this star can be measured directly, giving a diameter only one-seventh the size of the Sun.

Contents

Observation history

Proxima Centauri was discovered to share the same proper motion as Alpha Centauri in 1915 by Robert Innes while he was Director of the Union Observatory in Johannesburg, South Africa. The proper motion of a Star is the measurement of its change in position in the sky over time after Improper motions are accounted for Year 1915 ( MCMXV) was a Common year starting on Friday (link will display the full calendar of the Gregorian calendar (or a Common year Robert Thorburn Ayton Innes ( November 10 1861 Edinburgh &ndash March 13 1933) was a Scottish - South African Union Observatory was an astronomical Observatory located in the suburb Observatory, Johannesburg, South Africa. Johannesburg ( Pronounced /jō-hān'ĭs-bûrg'/ is the largest city in South Africa. The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa [8] Innes also suggested the name Proxima Centauri for the star. A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth In 1917 at the Royal Observatory at the Cape of Good Hope, the Dutch astronomer J. Year 1917 ( MCMXVII) was a Common year starting on Monday (link will display the full calendar of the Gregorian calendar (or a Common year The Cape of Good Hope ( Afrikaans: Kaap die Goeie Hoop, Kaap de Goede Hoop Cabo da Boa Esperança Persian Language: دماغه امید نیک Voûte measured the trigonometric parallax and determined that Proxima Centauri was indeed the same distance from the Sun as Alpha Centauri and hence was also the lowest luminosity star known at the time. Parallax is an apparent displacement or difference of orientation of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between Alpha Centauri (α Centauri / α Cen also known as Rigil Kentaurus, Rigil Kent, or Toliman, is the brightest Star in the southern Constellation A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth [9]

In 1951, Harlow Shapley announced that Proxima Centauri was a flare star. Harlow Shapley ( November 2 1885 &ndash October 20 1972) was an American Astronomer. Examination of past photographic records showed that the star displayed a measureable increase in magnitude about 8% of the time, making it the most active flare star then discovered. [10]

Characteristics

Red dwarfs in general are far too faint to be observable with the naked eye, and Proxima Centauri is no exception. It has an apparent magnitude of 11 while its absolute magnitude is a very dim 15. The apparent magnitude ( m) of a celestial body is a measure of its Brightness as seen by an observer on Earth, normalized to the value In Astronomy, absolute magnitude (also known as absolute visual magnitude) is the Apparent magnitude an object would have if it were at a standard 5. Even from Alpha Centauri A or B, Proxima would only be seen as a 5th magnitude star. Alpha Centauri (α Centauri / α Cen also known as Rigil Kentaurus, Rigil Kent, or Toliman, is the brightest Star in the southern Constellation [11] If the Sun were to become as dim as Proxima, all of the planets except Venus would be too faint to be seen with the naked eye, and even Venus at its brightest would be a barely visible 6th magnitude. The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University [12]

The relative size of Proxima Centauri (right) compared to its nearest neighbors.
The relative size of Proxima Centauri (right) compared to its nearest neighbors.

In 2002, VLTI used optical interferometry to measure an angular diameter of 1. The Very Large Telescope ( VLT) is a system of four separate Optical telescopes (the Antu telescope, the Kueyen telescope, the Melipal Optical interferometry combines two or more light waves in an optical instrument in such a way that Interference occurs between them The angular diameter of an object as seen from a given position is the "visual diameter" of the object measured as an angle 02 ± 0. 08 milliarcsec for Proxima Centauri. Because its distance is known, the actual diameter of Proxima Centauri can be calculated to be about 1/7 that of the Sun, or 1. 5 times that of Jupiter. [8] The estimated mass is only 12. 3% of a solar mass, or 129 Jupiter masses. The solar mass is a standard way to express Mass in Astronomy, used to describe the masses of other Stars and galaxies. Jupiter mass is the unit of Mass equal to one Jupiter (18986 × 1027 kg, 317 [3]

Because of its low mass, the interior of the star is completely convective, which means that energy is transferred to the exterior by the physical movement of plasma (rather than through radiative processes). The convection zone of a Star is the range of radii in which energy is transported primarily by Convection. The radiation zone is the middle zone in the Sun 's interior Energy travels out of the core into the radiation zone Convection is associated with the generation and storage of a magnetic field. A stellar magnetic field is a Magnetic field generated by the motion of conductive plasma inside a Main sequence ( Hydrogen -burning The magnetic energy from this field is released at the surface through stellar flares that briefly increase the overall luminosity of the star. A solar flare is a violent explosion in a star's (like the Sun 's atmosphere releasing as much Energy as 6 × 1025 Joules Solar flares These flares can grow as large as the star and reach temperatures of 2 million K[13]—hot enough to radiate X-rays. X-radiation (composed of X-rays) is a form of Electromagnetic radiation. [14] Indeed the quiescent X-ray luminosity of this star is roughly equal to that of the much larger Sun. However, the overall activity level of this star is considered relatively low compared to other M-class dwarfs. [15] This activity appears to vary with a period of roughly 442 days. [16]

Distance and kinematics

Based on the parallax of 772. Parallax is an apparent displacement or difference of orientation of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between 3 ± 2. 4 milliarcseconds measured by Hipparcos (and the more precise parallax determined using the Fine Guidance Sensors on the Hubble Space Telescope of 768. A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60 of one degree. Hipparcos (an Acronym for Hi gh P recision Par allax Co llecting S atellite) was an Astrometry mission The Hubble Space Telescope ( HST; also known colloquially as "the Hubble" or just "Hubble" is a space telescope that was carried into 7 ± 0. 3[17] milliarcseconds), Proxima Centauri is roughly 4. 2 light years from Earth, or 270,000 times more distant than the Sun. Its closest neighbors are Alpha Centauri A and B (at 0. Alpha Centauri (α Centauri / α Cen also known as Rigil Kentaurus, Rigil Kent, or Toliman, is the brightest Star in the southern Constellation 21 light years), the Sun, and Barnard's Star (at 6. Barnard's Star ( is a very low-mass Red dwarf Star approximately 6 Light-years away in the Constellation of Ophiuchus (the 6 light years). [18][19] From Earth's vantage point, Proxima is separated by 2. 2°[20] from Alpha Centauri, or four times the angular diameter of the full Moon. Alpha Centauri (α Centauri / α Cen also known as Rigil Kentaurus, Rigil Kent, or Toliman, is the brightest Star in the southern Constellation The angular diameter of an object as seen from a given position is the "visual diameter" of the object measured as an angle

At least among the known stars, Proxima Centauri has been the closest star to the Sun for about the last 32,000 years and will be so for about another 9,000 years, when it will be replaced by Barnard's Star. Barnard's Star ( is a very low-mass Red dwarf Star approximately 6 Light-years away in the Constellation of Ophiuchus (the [21] Proxima Centauri has a relatively large proper motion—moving 3. The proper motion of a Star is the measurement of its change in position in the sky over time after Improper motions are accounted for 85 arcseconds per year across the sky. A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60 of one degree. [22] In approximately 26,700 years, Proxima Centauri will make its closest approach to the Sun, coming within 3. 11 light years. [2] This star is orbiting through the Milky Way galaxy at a distance from the core that varies from 8. The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek Γαλαξίας (Galaxias sometimes referred to simply 313–9. 546 kpc and it has an orbital eccentricity of 0. In Astrodynamics, under standard assumptions, any Orbit must be of Conic section shape 069. [23]

From the time of the discovery of Proxima, it was suggested that it was likely to be a true companion of the Alpha Centauri double star system. Alpha Centauri (α Centauri / α Cen also known as Rigil Kentaurus, Rigil Kent, or Toliman, is the brightest Star in the southern Constellation At a distance to Alpha Centauri of just 0. 21 ly (15,000 ± 700 AU),[24] Proxima Centauri may be in orbit about Alpha, with an orbital period on the order of 500,000 years or more. The astronomical unit ( AU or au or au or sometimes ua) is a unit of Length based on the distance from the Earth to the The orbital period is the time taken for a given object to make one complete Orbit about another object For this reason, Proxima is sometimes referred to as Alpha Centauri C. Alpha Centauri (α Centauri / α Cen also known as Rigil Kentaurus, Rigil Kent, or Toliman, is the brightest Star in the southern Constellation Modern estimates, taking into account the small separation between and relative velocity of the stars, suggest that the chance of the observed alignment being a coincidence is roughly one in a million. [25]

The most recent observational work combined data from the Hipparcos satellite with ground-based observations and concluded that the data was consistent with the hypothesis that the three stars are truly a bound system. Hipparcos (an Acronym for Hi gh P recision Par allax Co llecting S atellite) was an Astrometry mission If so, Proxima would currently be near apastron (the furthest point in its orbit from the Alpha Centauri system). More accurate measurement of the radial velocity would be needed to confirm this conclusion. Radial velocity is the Velocity of an object in the direction of the line of sight (i [24]

RV-derived Upper Mass
Limits of Companion[26]
Orbital
period
(days)		Separation
(A. The orbital period is the time taken for a given object to make one complete Orbit about another object In Geometry, the semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolae U. )		Maximum
Mass
(× Jupiter)
500. 133. 7
6000. 698. 3
30001. 0022

Possible companions

Proxima Centauri, along with Alpha Centauri A and B, are among the "Tier 1" target stars for NASA's proposed Space Interferometry Mission (SIM). The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program The Space Interferometry Mission, also known as SIM PlanetQuest, is a planned space telescope being developed by the U Theoretically, SIM will be able to detect planets as small as three Earth-masses within two Astronomical Units of a "Tier 1" target. The astronomical unit ( AU or au or au or sometimes ua) is a unit of Length based on the distance from the Earth to the [27] Should a massive planet orbit Proxima Centauri, some displacement of the star would be expected to occur over the course of each orbit. If this orbital plane is inclined toward the line of sight from the Earth then this displacement would cause changes in the radial velocity of Proxima Centauri. Radial velocity is the Velocity of an object in the direction of the line of sight (i However no such shifts have yet been observed despite multiple radial velocity measurements. This puts significant constraints on the maximum mass that such a companion could possess. [26][17]

Possibility of life

See also: Habitability of red dwarf systems

The TV documentary Alien Worlds hypothesizes that a life-sustaining planet could theoretically exist orbiting Proxima Centauri or other red dwarf stars. Determining the habitability of red dwarf systems could help reveal how likely Extraterrestrial life is to exist as Red dwarfs make up a majority of all the stars Aurelia and Blue Moon are hypothetical examples of a Planet and a moon on which Extraterrestrial life could evolve Such a planet would have to be orbiting 0. 032 AU from Proxima Centauri, and would have a year lasting 6. 3 days. Since Proxima Centauri is a flare star this could cause difficulties although the scientists thought these obstacles could be overcome (see Continued theories). Aurelia and Blue Moon are hypothetical examples of a Planet and a moon on which Extraterrestrial life could evolve Flares could cause problems with the atmosphere of any planet in the habitable zone. In Astronomy a habitable zone ( HZ) is a region of space where conditions are favorable for Life as it may be found on Earth.

"No one found any showstoppers to habitability," says Gibor Basri of the University of California, Berkeley. The University of California ( UC) is a Public university system in the state of California. One concern was that because M dwarfs frequently produce flares, the resulting torrents of charged particles could strip the atmosphere off any nearby planet. If the planet had a magnetic field, though, it would deflect the particles from the atmosphere. And even the slow rotation of a tidally locked M-dwarf planet—it spins once for every time it orbits its star—would be enough to generate a magnetic field as long as part of the planet's interior remained molten. [28]

Other scientists, especially proponents of the Rare Earth hypothesis, disagree that red dwarf stars could sustain life. In Planetary astronomy and Astrobiology, the Rare Earth hypothesis argues that the emergence of complex Multicellular life ( Metazoa

Interstellar travel

Proxima Centauri has been suggested as a logical first destination for interstellar travel, although as a flare star it would not be particularly hospitable. Interstellar space travel is unmanned or manned Travel between Stars The concept of interstellar travel in Starships is a staple in Science fiction A flare star is a Variable star which can undergo unpredictable dramatic increases in brightness for a few minutes However, even at the fastest speed currently attained by a manned vehicle the journey to Proxima Centauri would take ~32,000 years. This is a list of spaceflight records. Most of these records relate to Human spaceflights but some unmanned and canine records are included [29] Project Longshot could theoretically reach the Alpha Centauri system in about 100 years by means of nuclear pulse propulsion. Project Longshot is a design for an interstellar Spacecraft, an unmanned probe intended to fly to Alpha Centauri powered by Nuclear pulse propulsion. [30]

See also

References

  1. ^ a b c d e f g h i j SIMBAD query result: V* V645 Cen -- Flare Star. The Planetary systems of Stars other than the Sun and its Solar System are a staple element in much Science fiction. Alpha Centauri (α Centauri / α Cen also known as Rigil Kentaurus, Rigil Kent, or Toliman, is the brightest Star in the southern Constellation This list of stars nearest to the Earth is ordered by increasing distance out to a maximum of 5 Parsecs (16 To help compare different Orders of magnitude, the following list describes various Lengths between 1 Centre de Données astronomiques de Strasbourg. Retrieved on 2007-07-09. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 455 - Roman military commander Avitus is proclaimed Emperor of the Western Roman Empire. —some of the data is located under "Measurements".
  2. ^ a b García-Sánchez, J. ; Weissman, P. R. ; Preston, R. A. ; Jones, D. L. ; Lestrade, J. -F. ; Latham, D. W. ; Stefanik, R. P. ; Paredes, J. M. (2001). "Stellar encounters with the solar system". Astronomy and Astrophysics 379: 634–659.  
  3. ^ a b c d e f Kervella, Pierre; Thevenin, Frederic. "A Family Portrait of the Alpha Centauri System: VLT Interferometer Studies the Nearest Stars", ESO, March 15, 2003. Retrieved on 2007-07-09. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 455 - Roman military commander Avitus is proclaimed Emperor of the Western Roman Empire.  
  4. ^ Ségransan, D. ; Kervella, P. ; Forveille, T. ; Queloz, D. (2003). "First radius measurements of very low mass stars with the VLTI". Astronomy and Astrophysics 397: L5–L8.  
  5. ^ G. Fritz Benedict et al (1998). "Photometry of Proxima Centauri and Barnard's Star Using Hubble Space Telescope Fine Guidance Sensor 3: A Search for Periodic Variations". The Astronomical Journal 116 (1): 429-439.  
  6. ^ Latin Resources. Joint Association of Classical Teachers. Retrieved on 2007-07-15. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1099 - First Crusade: Christian soldiers take the Church of the Holy Sepulchre in Jerusalem after the final
  7. ^ Distances in the Universe. ESO.
  8. ^ a b Queloz, Didier (November 29, 2002). How Small are Small Stars Really? VLT Interferometer Measures the Size of Proxima Centauri and Other Nearby Stars. European Southern Observatory. Retrieved on 2007-07-09. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 455 - Roman military commander Avitus is proclaimed Emperor of the Western Roman Empire.
  9. ^ Voûte, J. (1917). "A 13th magnitude star in Centaurus with the same parallax as α Centauri". Monthly Notices of the Royal Astronomical Society 77: 650-651.  
  10. ^ Shapley, Harlow (1951). "Proxima Centauri as a Flare Star". Proceedings of the National Academy of Sciences of the United States of America 37 (1): 15-18.  
  11. ^ Proxima Centauri UV Flux Distribution. ESA/Laboratory for Space Astrophysics and Theoretical Physics. Retrieved on 2007-07-11. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 911 - Signing of the Treaty of Saint-Clair-sur-Epte between Charles the Simple and Rollo of Normandy.
  12. ^ The difference in absolute magnitude between Proxima Centauri and the Sun is 15. 49 - 4. 83 = 10. 66. Venus reaches a maximum apparent magnitude of -4. 6, so the corresponding magnitude of Venus in the same orbit around Proxima Centauri would be -4. 6 + 10. 66 = 6. 06.
  13. ^ 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 61 (2): 1140–1146.  
  14. ^ Staff (August 30, 2006). Proxima Centauri: The Nearest Star to the Sun. Harvard-Smithsonian Center for Astrophysics. Retrieved on 2007-07-09. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 455 - Roman military commander Avitus is proclaimed Emperor of the Western Roman Empire.
  15. ^ Wood, B. E. ; Linsky, J. L. ; Müller, H. -R. ; Zank, G. P. (2001). "Observational Estimates for the Mass-Loss Rates of α Centauri and Proxima Centauri Using Hubble Space Telescope Lyα Spectra". The Astrophysical Journal 547 (1): L49-L52.  
  16. ^ Cincunegui, C. ; Díaz, R. F. ; Mauas, P. J. D. (2007). "A possible activity cycle in Proxima Centauri". Astronomy and Astrophysics 461 (3): 1107-1113. doi:10.1051/0004-6361:20066027. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
  17. ^ a b G. Fritz Benedict et al (1999). "Interferometric Astrometry of Proxima Centauri and Barnard's Star Using HUBBLE SPACE TELESCOPE Fine Guidance Sensor 3: Detection Limits for Substellar Companions". The Astronomical Journal 118 (2): 1086-1100.  
  18. ^ Barnard's Star. SolStation. Retrieved on 2007-08-06. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1538 - Bogotá, Colombia, is founded by Gonzalo Jiménez de Quesada.
  19. ^ Alpha Centauri 3. SolStation. Retrieved on 2007-07-21. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 356 BC - Herostratus sets fire to the Temple of Artemis in Ephesus, one of the Seven Wonders of the World
  20. ^ Wargelin, Bradford J. ; Drake, Jeremy J. (2002). "Stringent X-Ray Constraints on Mass Loss from Proxima Centauri". The Astrophysical Journal 587: 503-514.  
  21. ^ Bell, George H. (2001). The Search for the Extrasolar Planets: A Brief History of the Search, the Findings and the Future Implications, Section 2.. Arizona State University. Retrieved on 2007-07-09. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 455 - Roman military commander Avitus is proclaimed Emperor of the Western Roman Empire. — Full description of the Van de Kamp planet controversy.
  22. ^ Benedict, G. F. et al. "Astrometric Stability and Precision of Fine Guidance Sensor #3: The Parallax and Proper Motion of Proxima Centauri". Proceedings of the HST Calibration Workshop: 380-384. Retrieved on 2007-07-11. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 911 - Signing of the Treaty of Saint-Clair-sur-Epte between Charles the Simple and Rollo of Normandy.  
  23. ^ Allen, C. ; Herrera, M. A. (1998). "The galactic orbits of nearby UV Ceti stars". Revista Mexicana de Astronomia y Astrofisica 34: 37–46.  
  24. ^ a b Wertheimer, Jeremy G. ; Laughlin, Gregory (2006). "Are Proxima and α Centauri Gravitationally Bound?". The Astronomical Journal 132 (5): 1995-1997. doi:10.1086/507771. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
  25. ^ Matthews, Robert; Gilmore, Gerard (1993). "Is Proxima really in orbit about Alpha CEN A/B?". MNRAS 261: L5.  
  26. ^ a b Kürster, M. et al (1999). "Precise radial velocities of Proxima Centauri" (PDF). Astronomy & Astrophysics Letters 344: L5-L8.  
  27. ^ Watanabe, Susan (October 18, 2006). Planet-Finding by Numbers. NASA JPL. Retrieved on 2007-07-09. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 455 - Roman military commander Avitus is proclaimed Emperor of the Western Roman Empire.
  28. ^ Alpert, Mark (November 2005). Red Star Rising. Scientific American. Retrieved on 2008-05-19. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1535 - French explorer Jacques Cartier sets sail on his second voyage to North America with three ships 110 men and
  29. ^ The distance to Proxima Centauri is:
    (4. 22 ly) × (9. 46 × 1012 km/ly) = 4. 0 × 1013 km
    A year is about 32 million seconds, so completing the journey in 32,000 years (or ~1011 seconds) would require a (non-relativistic) velocity of
    (4. 0 × 1013 km) / (1. 0 × 1012 seconds) = 40 km/s.
    By comparison, the Apollo 10 achieved a record velocity of 11 km/s.
  30. ^ Beals, K. A. ; Beaulieu, M. ; Dembia, F. J. ; Kerstiens, J. ; Kramer, D. L. ; West, J. R. ; Zito, J. A. (1988). Project Longshot, an Unmanned Probe to Alpha Centauri. NASA-CR-184718. U. S. Naval Academy. Retrieved on 2008-06-13. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1525 - Martin Luther marries Katharina von Bora, against the Celibacy rule decreed by the Roman Catholic Church for

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Proxima Centauri

-proper noun

  1. (astronomy) A red dwarf star, part of the Alpha Centauri system. It is the nearest star to Earth's solar system.
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