Changes

| image          =Position_Alpha_Ori.png

| image          =Position_Alpha_Ori.png

| designation    =Alpha Orionis

| designation    =Alpha Orionis

| rightascension  =05^h 55^m 10.3053^s  

| rightascension  =05^h 55^m 10.3053^s<ref name=simbad>[https://simbad.u-strasbg.fr/simbad/sim-id?Ident=Betelgeuse&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id Betelgeuse] from the [http://simbad.u-strasbg.fr/simbad SIMBAD Astronomical Database]</ref>

| declination    =+07^o 24′ 25.426

| declination    =+07° 24′ 25.4304<ref name=simbad/>

| distance        =640 ± 140 ly

| distance        =643 ± 146 ly<ref name=constellation-guide>{{cite web|url=https://www.constellation-guide.com/betelgeuse/|title=Betelgeuse|accessdate=2018-12-31}}</ref>

| constellation  =Orion

| constellation  =Orion

| type            =Supergiant{{!}}Supergiant star

| type            =Supergiant{{!}}Supergiant star

| dimensions      =

| dimensions      =

| magnitude      =Apparent Mag: 0.58 (0.3 to 1.2)<br/>Absolute Mag: -5.14  

| magnitude      =Apparent Mag: 0.58 (0.3 to 1.2)<ref name=constellation-guide/><br/>Absolute Mag: -5.14<ref name=constellation-guide/>

| redshift        =

| redshift        =

| radvelocity    =<nowiki>+21.0 km/s</nowiki>

| radvelocity    =21.9 ± 0.51 km/s<ref name=simbad/>

| propmotion      =RA: 24.95 ± 0.08 mas/yr<br/>Dec.: 9.56 ± 0.15 mas/yr

| propmotion      =RA: 27.54 mas/yr<ref name=simbad/><br/>Dec.: 11.30 mas/yr<ref name=simbad/>

| parallax        =5.07 ± 1.10 mas

| parallax        =6.55 ± 0.83 mas<ref name=simbad/>

}}

}}

'''Betelgeuse''', or '''Alpha Orionis''' is an orange-reddish star located in the northeast part the constellation [[Orion]]. The star is typically the second brightest in the [[constellation]], although as a [[variable star]], its apparent magnitude can exceed from time to time, that of [[Rigel]], normally the brightest star of Orion.

'''Betelgeuse''', or '''Alpha Orionis''' is an orange-reddish star located in the northeast part the constellation [[Orion]].<ref name=constellation-guide/> The star is typically the second brightest in the [[constellation]], although as a [[variable star]], its apparent magnitude can exceed from time to time, that of [[Rigel]], normally the brightest star of Orion.

==Entymology==

==Entymology==

The name Betelgeuse itself is a corruption of the Arabic يد الجوزاء ''yad al-jawzā'' ("hand of the central one"). Other names various Arabic authors have given the star are ''Al Mankib'', (the Shoulder); ''Al Dhira'', (the Arm); and ''Al Yad al Yamma'', (the Right Hand). As one of the most recognizable stars in the night sky, it has many other names throughout the world including ''Ardra'' in [[Hindi]], ''Klaria'', meaning an Armlet in [[Coptic]], ''Bašn'' meaning the Arm in [[Persian]], and ''Shēnsùsì'' (参宿四, the Fourth Star of the Constellation of Three Stars), in [[Chinese]].<ref>http://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Orion*.html</ref>

The name Betelgeuse itself is a corruption of the Arabic يد الجوزاء ''yad al-jawzā'' ("hand of the central one"). Other names various Arabic authors have given the star are ''Al Mankib'', (the Shoulder); ''Al Dhira'', (the Arm); and ''Al Yad al Yamma'', (the Right Hand). As one of the most recognizable stars in the night sky, it has many other names throughout the world including ''Ardra'' in [[Hindi]], ''Klaria'', meaning an Armlet in [[Coptic]], ''Bašn'' meaning the Arm in [[Persian]], and ''Shēnsùsì'' (参宿四, the Fourth Star of the Constellation of Three Stars), in [[Chinese]].<ref name="lore">Allen, Richard Hinkley (1963). Star Names, Their Lore and Meaning. New York: Dover. ISBN 0-486-21079-0. Available online: {{cite web|url=http://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Orion*.html|title=Orion, the Giant, Hunter, and Warrior|accessdate=2018-12-31}}</ref>

==Description==

==Description==

Betelgeuse is a luminous red [[supergiant]] of spectral and luminosity type M1-2 Ib, with a surface temperature of around 3650 K. The star has an "average" apparent magnitude of 0.58 in the night sky, making it the 9th brightest star.<ref>http://simbad.u-strasbg.fr/simbad/sim-id?Ident=betelgeuse</ref> Being a [[variable star]], its magnitude varies between 0.3 and 1.1 over multiple periods in cycles of variability which have been observed to be between six months to six years on average.

Betelgeuse is a luminous red [[supergiant]] of spectral and luminosity type M1-2 Ib, with a surface temperature of around 3650 K. The star has an "average" apparent magnitude of 0.58 in the night sky, making it the 9th brightest star.<ref name=simbad/> Being a [[variable star]], its magnitude varies between 0.3 and 1.1 over multiple periods in cycles of variability which have been observed to be between six months to six years on average.

One area of debate is the distance of the star. Using the most recent and modern direct [[parallax]] measurements resulted in a distance of 495 light years. However, using the star's natural radio emissions for parallax yields a distance of 640 light years. Allowing for the high amount of [[infrared]] [[radiation]] emitted from the star and the absorption of light by its circumstellar dust disk, a compromise distance of 570 light years is most often used.<ref name="Bettle">http://stars.astro.illinois.edu/sow/betelgeuse.html</ref>

One area of debate is the distance of the star. Using the most recent and modern direct [[parallax]] measurements resulted in a distance of 495 light years. However, using the star's natural radio emissions for parallax yields a distance of 640 light years.<ref name=constellation-guide/> Allowing for the high amount of [[infrared]] [[radiation]] emitted from the star and the absorption of light by its circumstellar dust disk, a compromise distance of 570 light years is most often used.<ref name="Bettle">{{cite web|url=http://stars.astro.illinois.edu/sow/betelgeuse.html|title=Betelgeuse|accessdate=2018-12-31}}</ref>

At the compromise distance of 570 light years, the star has a total bolometric luminosity some 85,000 times that of the [[Sun]]. Because Betelgeuse is so immense in size, it is easy to measure its angular diameter, which is 0.054 seconds of arc. This places the radius of the star at some 3.6 AU, or as great as that of the [[asteroid belt]] (with a total diameter of 7.2 AU).<ref>http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1992MNRAS.257..369W</ref> Measuring the star in [[ultraviolet]] light has suggested its radius is over 8 AU in size, more than twice the distance found at optical wavelengths.<ref>http://www.cfa.harvard.edu/news/archive/betel97.html</ref>

At the compromise distance of 570 light years, the star has a total bolometric luminosity some 85,000 times that of the [[Sun]]. Because Betelgeuse is so immense in size, it is easy to measure its angular diameter, which is 0.054 seconds of arc.This places the radius of the star at some 3.6 AU, or as great as that of the [[asteroid belt]] (with a total diameter of 7.2 AU).<ref>Wilson, R., Baldwin, J., Buscher, D. and Warner, P. (1992). High-resolution imaging of Betelgeuse and Mira. ''Monthly Notices of the Royal Astronomical Society'', 257(3), pp.369-376. [https://ui.adsabs.harvard.edu/#abs/1992MNRAS.257..369W/abstract Bincode:1992MNRAS.257..369W]</ref> Measuring the star in [[ultraviolet]] light has suggested its radius is over 8 AU in size, more than twice the distance found at optical wavelengths.<ref>{{cite web|url=http://www.cfa.harvard.edu/news/archive/betel97.html|title=HST OBSERVATIONS OF THE PULSATING STAR BETELGEUSE|accessdate=2018-12-31}}</ref>

==Future Supernova==

==Future Supernova==

Due to its extremely high mass though, the star is fusing core [[helium]] into [[carbon]] and [[oxygen]], which has swelled the outer layers of gas in the star, causing its great size. Eventually the star will fuse heavier elements all the way to [[iron]] before collapsing into a [[supernova]].<ref>https://books.google.com/books?id=Aq24O7B4ehoC&dq=the+hundred+greatest+stars&printsec=frontcover&source=bn&hl=en&ei=PNMnS5-BHI3anAeqsLm1DQ&sa=X&oi=book_result&ct=result&resnum=4&ved=0CBwQ6AEwAw#v=onepage&q=Betelgeuse&f=false</ref>  Such an explosion would be so bright, it would outshine the full [[moon]].<ref name="Bettle"/> A date for the nova has been set by some at 2012; others however are more skeptical, as astronomers have claimed such a prediction is impossible to tell.<ref>http://www.foxnews.com/scitech/2011/01/21/betelgeuse-explode-scientists-say/?test=faces</ref>

Due to its extremely high mass though, the star is fusing core [[helium]] into [[carbon]] and [[oxygen]], which has swelled the outer layers of gas in the star, causing its great size. Eventually the star will fuse heavier elements all the way to [[iron]] before collapsing into a [[supernova]].<ref>{{cite web|url=https://books.google.com/books?id=Aq24O7B4ehoC&dq=the+hundred+greatest+stars&printsec=frontcover&source=bn&hl=en&ei=PNMnS5-BHI3anAeqsLm1DQ&sa=X&oi=book_result&ct=result&resnum=4&ved=0CBwQ6AEwAw#v=onepage&q=Betelgeuse&f=false|title=The Hundred Greatest Stars|accessdate=2018-12-31}}</ref>  Such an explosion would be so bright, it would outshine the full [[moon]].<ref name="Bettle"/> A date for the nova has been set by some at 2012; others however are more skeptical, as astronomers have claimed such a prediction is impossible to tell.<ref>{{cite web|url=http://www.foxnews.com/scitech/2011/01/21/betelgeuse-explode-scientists-say/?test=faces|title=Dying Star Betelgeuse Won't Explode in 2012, Experts Say|accessdate=2018-12-31}}</ref>

The [[UC Berkeley|UC Berkeley's]] Infrared Spatial Interferometer (ISI) atop [[Mt. Wilson Observatory]] in Southern [[California]] collected evidence over 15 consecutive years, showing the star is constantly contracting.<ref>http://esciencenews.com/articles/2009/06/09/red.giant.star.betelgeuse.mysteriously.shrinking</ref> The star is estimated to have shrunk 15 percent in size since 1993 and the rate of contraction is increasing, the total observed contraction is equal to half an astronomical unit, or equivalent of the distance of Venus from the sun.<ref>http://www.berkeley.edu/news/media/releases/2009/06/09_betelim.shtml</ref> It is speculated this is the behavior expected for a star that has reached the end of its life and the beginning of gravitational collapse. Because of the mass of Betelgeuse, the result of the supernova explosion will be either a [[neutron star]] or even a [[black hole]].

The [[UC Berkeley|UC Berkeley's]] Infrared Spatial Interferometer (ISI) atop [[Mt. Wilson Observatory]] in Southern [[California]] collected evidence over 15 consecutive years, showing the star is constantly contracting.<ref name=shrink>{{cite web|url=http://esciencenews.com/articles/2009/06/09/red.giant.star.betelgeuse.mysteriously.shrinking|title=Red giant star Betelgeuse is mysteriously shrinking|accessdate=2018-12-31}}</ref> The star is estimated to have shrunk 15 percent in size since 1993 and the rate of contraction is increasing, the total observed contraction is equal to half an astronomical unit, or equivalent of the distance of Venus from the sun.<ref name=shrink/> It is speculated this is the behavior expected for a star that has reached the end of its life and the beginning of gravitational collapse. Because of the mass of Betelgeuse, the result of the supernova explosion will be either a [[neutron star]] or even a [[black hole]].

Updated high resolution images of Betelgeuse obtained by the [[Very Large Telescope]] in [[Chile]] in July 2009, revealed new evidence that Betelgeuse is rapidly shedding mass. A large gas plume is shown to be surrounding the star.<ref>http://www.eso.org/gallery/v/ESOPIA/Stars/phot-27b-09-fullres.tif.html</ref> If the plume was in our solar system, it would extend to the orbit of [[Jupiter]]. The plume is viewed as further evidence by scientists the star is very near the end of its life.<ref>http://antwrp.gsfc.nasa.gov/apod/ap090805.html</ref>

Updated high resolution images of Betelgeuse obtained by the [[Very Large Telescope]] in [[Chile]] in July 2009, revealed new evidence that Betelgeuse is rapidly shedding mass. A large gas plume is shown to be surrounding the star.<ref>{{cite web|url=https://www.eso.org/public/unitedkingdom/news/eso1121/|title=The Flames of Betelgeuse|accessdate=2018-12-31}}</ref> If the plume was in our solar system, it would extend to the orbit of [[Jupiter]]. The plume is viewed as further evidence by scientists the star is very near the end of its life.<ref>{{cite web|url=https://apod.nasa.gov/apod/ap090805.html|title=Betelgeuse Resolved |accessdate=2018-12-31}}</ref>

==References==

==References==

[[Category:Astronomy]]

[[Category:Astronomy]]