Procyon 25006 224827512 2008-07-10T16:24:21Z Kbdankbot 6505923 Robot - move category per [[WP:CFD|CFD]] [[Wikipedia:Categories for discussion/Log/2008 July 2|2008 July 2]] :''This article is about the star. '''Procyon''' is also the mammalian genus to which [[Procyon (genus)|raccoons]] belong. '' {{Starbox begin | name=Procyon A/B }} {{Starbox image | image=[[Image:Position Alpha Cmi.png|250px]] | caption=The position of Procyon. }} {{Starbox observe | epoch=J2000 | constell=[[Canis Minor]] | ra=07h 39m 18.1/17.7s | dec=+05° 13' 29/20" | appmag_v=0.34/10.7 }} {{Starbox character | class=F5 IV-V/DA | b-v=0.40/0.0 | u-b=&minus;0.01 | variable=? }} {{Starbox astrometry | radial_v=&minus;3.2 | prop_mo_ra=&minus;716.57 | prop_mo_dec=&minus;1034.58 | parallax=286.05 | p_error=0.81 | absmag_v=2.65/13.04 }} {{Starbox detail| mass=1.50/0.60 | radius=1.86/0.02 | luminosity=7.73/0.00055 | temperature=6,650/9,700 | metal=110% Sun| gravity=4.0/8.0<ref>{{cite journal | author=Provencal, J. L.; Shipman, H. L.; Koester, Detlev; Wesemael, F.; Bergeron, P. | title=Procyon B: Outside the Iron Box | journal=The Astrophysical Journal | year=2002 | volume=568 | issue=1 | pages=324–334 | url=http://adsabs.harvard.edu/abs/2002ApJ...568..324P | accessdate=2007-06-02 | doi = 10.1086/338769 <!--Retrieved from CrossRef by DOI bot--> }}</ref> | rotation= | age=1.7 &times; 10<sup>9</sup> }} {{Starbox visbin | name=Procyon B | period=40.82 | axis=4.27 | eccentricity=0.41 | inclination=31.9 | node=284.8 | periastron=1967.86 }} {{Starbox catalog | names=α&nbsp;Canis Minoris, 10&nbsp;Canis Minoris, [[General Catalogue of Trigonometric Parallaxes|GCTP]]&nbsp;1805.00, [[Harvard Revised catalogue|HR]]&nbsp;2943, [[Bonner Durchmusterung|BD]]+05°1739, [[Henry Draper catalogue|HD]]&nbsp;61421, [[Luyten Half-Second catalogue|LHS]]&nbsp;233, [[Gliese-Jahreiss catalogue|GJ]]&nbsp;280, [[Hipparcos catalogue|HIP]]&nbsp;37279, GC&nbsp;10277, [[Star catalogue#ADS|ADS]]&nbsp;6251, CCDM&nbsp;07393+0514, TD1&nbsp;10647. }} {{Starbox reference | Simbad=HR+2943 }} {{Starbox end}} '''Procyon''' ({{pron-en|'proʊsɪən}}) (α CMi / α Canis Minoris / [[alpha (letter)|Alpha]] Canis Minoris) is the brightest [[star]] in the [[constellation]] [[Canis Minor]]. To the naked eye, it appears to be a single star, the [[list of brightest stars|eighth brightest]] in the night sky with a visual [[apparent magnitude]] of 0.34. It is actually a [[binary star]] system, consisting of a white [[main sequence]] star of [[spectral type]] F5 IV-V, named '''Procyon A''', and a faint [[white dwarf]] companion of spectral type DA, named '''Procyon B'''. The reason for its brightness is not its intrinsic luminosity but its closeness to the [[Sun]]; at a distance of 3.5 [[parsec|pc]] or 11.41 [[light year]]s, Procyon is one of our [[List of nearest stars|near neighbours]]. Its closest neighbour is [[Luyten's star]], 0.34 pc or 1.11 ly away. Procyon forms one of the three [[Vertex (geometry)|vertices]] of the [[Winter Triangle]], along with [[Sirius]] and [[Betelgeuse]]. ==System== Procyon A is a white star of spectral type F5; it is 1.4 times the mass, twice the diameter, and 7.5 times more [[luminosity|luminous]] than the [[Sun]].<ref>Gatewood G. and Han I., "An astrometric study of Procyon". Astron. J., 131, 1015-1021 (2006) - February 2006. http://simbad3.u-strasbg.fr/cgi-bin/cdsbib4?2006AJ....131.1015G Accessed 2/3/07.</ref>,<ref>Astron. Astrophys., 413, 251-256 (2004) - January(I) 2004 Kervella et al., "The diameter and evolutionary state of Procyon A. Multi-technique modeling using asteroseismic and interferometric constraints". Astron. Astrophys., 413, 251-256 (2004) - January(I) 2004 http://simbad3.u-strasbg.fr/cgi-bin/cdsbib4?2004A%26A...413..251K Accessed 2/3/07.</ref>,<ref>Solstation.com, "Procyon 2". http://www.solstation.com/stars/procyon2.htm Accessed 2/3/07.</ref>. It is bright for its spectral class, suggesting that it is a ''[[subgiant]]'' that has completely [[nuclear fusion|fused]] its core hydrogen into helium, and begun to expand as "burning" moves outside the core. As it continues to expand, the star will eventually swell to about 80 to 150 times its current diameter and become a red or orange color. This will probably happen within 10 to 100 million years. It is expected that the Sun will also go through this process when hydrogen fusion ceases at its core. <!-- Deleted image removed: [[Image:Procyonorbitillustration.JPG|thumb|250px|left|An illustration of Procyon B's orbit, with Procyon A treated as fixed. This is how the orbit would appear from above, not as it actually appears from Earth.]] --> Like Sirius B, Procyon's companion is a white dwarf that was inferred from [[astrometry|astrometric]] data long before it was observed; though its orbit was known as far back as 1861, it was not visually confirmed until 1896.<ref>Robert Burnham Jr., ''Burnham's Celestial Handbook'' (New York: Dover Publications Inc., 1978), p. 450.</ref> It is even more difficult to observe from Earth than Sirius B, due to a greater [[apparent magnitude]] difference and smaller angular separation from its primary. The average separation of the two components is 15 [[astronomical unit|AU]]s, a little less than the distance between [[Uranus (planet)|Uranus]] and the Sun, though the eccentric orbit carries them as close as 9 AUs and as far as 21.<ref>Solstation.com</ref> At 0.6 [[solar mass]]es, Procyon B is considerably less massive than Sirius B; however, the peculiarities of [[degenerate matter]] ensure that it is larger than its more famous neighbor, with an estimated radius of ~8600 [[kilometer|km]], versus ~5800 km for Sirius B.<ref>Provencal et al., "Procyon B: outside the iron box". Astrophys. J., 568, 324-334 (2002) - March(III) 2002 http://simbad3.u-strasbg.fr/cgi-bin/cdsbib4?2002ApJ...568..324P Accessed 2/3/07.</ref>,<ref>Holberg et al., "Sirius B: A New, More Accurate View". The Astrophysical Journal, 497: 935-942, 1998 April 20 http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v497n2/36707/36707.html?erFrom=5484718977321095316Guest Accessed 2/3/07.</ref> With a surface temperature of 7740 [[Kelvin|K]], it is also much cooler than Sirius B; this is a testament to its lesser mass and greater age. ===Oscillations controversy=== <!-- Commented out because image was deleted: [[Image:Procyon-v-sol.MOST.png|thumb|left|Schematic illustration of light variations of Sun and Procyon, from MOST website]] --> In late June of 2004, [[Canada]]'s orbital [[MOST satellite telescope]] carried out a 32-day survey of Procyon A. The continuous optical monitoring was intended to confirm [[solar-like oscillations]] in its brightness observed from Earth and to permit [[asteroseismology]]. No oscillations were detected and the authors concluded that the theory of stellar oscillations may need to be reconsidered.<ref>Matthews, J. M. et al: "No stellar p-mode oscillations in space-based photometry of Procyon" ''Nature 430:921 (2004)'' http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2004Natur.430...51M&amp;db_key=AST&amp;data_type=HTML&amp;format=&amp;high=44cedd215812216</ref> However others argued that the non-detection was consistent with published ground-based [[radial velocity]] observations of [[solar-like oscillations]].<ref>Bouchy, F. et al.: "Oscillations on the star Procyon" ''Nature 432:7015 (2004)'' http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005astro.ph.10303B&amp;db_key=PRE&amp;data_type=HTML&amp;format=&amp;high=44cedd215813511</ref><ref>Bedding, T. R. et al.: "The non-detection of oscillations in Procyon by MOST: Is it really a surprise?" ''Astronomy and Astrophysics, 432:L43 (2005)'' http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005A%26A...432L..43B&amp;db_key=AST</ref> Photometric measurements from the [[NASA]] [[Wide Field Infrared Explorer]] (WIRE) satellite from 1999 and 2000 showed evidence of granulation ([[convection]] near the surface of the [[star]]) and [[solar-like oscillations]].<ref>Bruntt, H. et al.: "Evidence for Granulation and Oscillations in Procyon from Photometry with the WIRE Satellite" ''The Astrophysical Journal, 633:440 (2005)'' http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005ApJ...633..440B&db_key=AST&nosetcookie=1</ref> Unlike the MOST result, the variation seen in the WIRE [[photometry]] was in agreement with [[radial velocity]] measurements from the ground. ==Etymology and cultural significance== Its name comes from the Greek ''προκύον'' (''prokúon''), meaning "before the dog", since it precedes the "Dog Star" [[Sirius]] as it travels across the sky due to [[Earth]]'s rotation. (Although Procyon has a greater [[right ascension]], it also has a more northerly [[declination]], which means it will rise above the [[horizon]] earlier than Sirius from most northerly latitudes.) These two [[dog star]]s are referred to in the most ancient literature and were venerated by the [[Babylon|Babylonians]] and the [[Egypt|Egyptians]]. It is known as 南河三 (Nánhésān, the Third Star in the Southern River) in Chinese. ==References== {{reflist}} ==See also== * [[List of nearest stars]] * [[List of brightest stars]] * [[Stars in astrology#Procyon|Procyon in astrology]] * [[Stars and planetary systems in fiction#Procyon|Procyon in fiction]] ==External links== * [http://www.solstation.com/stars/procyon2.htm Sol Station &mdash; Procyon] [[Category:Canis Minor constellation]] [[Category:Binary stars]] [[Category:Bayer objects|Canis Minoris, Alpha]] [[Category:HD and HDE objects|061421]] [[Category:White dwarfs]] [[Category:F-type main sequence stars]] [[Category:F-type subgiants]] [[Category:Stars with proper names]] [[ca:Procyon]] [[cs:Prokyon]] [[de:Prokyon]] [[el:Προκύων]] [[es:Procyon (estrella)]] [[fa:شعرای شامی]] [[fr:Alpha Canis Minoris]] [[ko:프로키온]] [[it:Procione (astronomia)]] [[lb:Procyon (Stär)]] [[lt:Prokionas]] [[nl:Procyon (ster)]] [[ja:プロキオン]] [[nds:Prokyon]] [[pl:Procjon]] [[pt:Procyon (estrela)]] [[ru:Процион]] [[sk:Prokyón]] [[fi:Procyon]] [[sv:Procyon]] [[tr:Procyon]] [[uk:Проціон]] [[vo:Procyon]] [[zh:南河三]]