Epsilon Carinae: Difference between revisions
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{{short description| |
{{short description|Binary star in the constellation Carina}} |
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{{Starbox begin |
{{Starbox begin |
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| name=ε Carinae |
| name=ε Carinae |
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{{Starbox observe |
{{Starbox observe |
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| epoch = J2000 |
| epoch = J2000 |
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| ra = {{RA|08|22|30.83526}}<ref name=aaa474_2_653/> |
| ra = {{RA|08|22|30.83526}}<ref name="aaa474_2_653" /> |
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| dec = {{DEC|-59|30|34.1431}}<ref name=aaa474_2_653/> |
| dec = {{DEC|-59|30|34.1431}}<ref name="aaa474_2_653" /> |
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| appmag_v = 1.86<ref name=clpl4_99/> (2.166/4.121)<ref name=aaa356_141/> |
| appmag_v = 1.86<ref name="clpl4_99" /> (2.166/4.121)<ref name="aaa356_141" /> |
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| constell = [[Carina (constellation)|Carina]] |
| constell = [[Carina (constellation)|Carina]] |
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}} |
}} |
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{{Starbox character |
{{Starbox character |
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| class = K3 III<ref name=houk1978/> + B2 Vp<ref name=apjss119_1_83/> |
| class = K3 III<ref name="houk1978" /> + B2 Vp<ref name="apjss119_1_83" /> |
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| b-v = +1.27<ref name=clpl4_99/> |
| b-v = +1.27<ref name="clpl4_99" /> |
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| u-b = +0.19<ref name=clpl4_99/> |
| u-b = +0.19<ref name="clpl4_99" /> |
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| variable = [[Eclipsing binary|Eclipsing]] (suspected)<ref name=yalebsc/> |
| variable = [[Eclipsing binary|Eclipsing]] (suspected)<ref name="yalebsc" /> |
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}} |
}} |
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{{Starbox astrometry |
{{Starbox astrometry |
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| radial_v = +11.6<ref name=rgcrv/> |
| radial_v = +11.6<ref name="rgcrv" /> |
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| prop_mo_ra = –25.52<ref name=aaa474_2_653/> |
| prop_mo_ra = –25.52<ref name="aaa474_2_653" /> |
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| prop_mo_dec = 22.72<ref name=aaa474_2_653/> |
| prop_mo_dec = 22.72<ref name="aaa474_2_653" /> |
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| parallax = 5.39 |
| parallax = 5.39 |
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| p_error = 0.42 |
| p_error = 0.42 |
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| parallax_footnote = <ref name=aaa474_2_653/> |
| parallax_footnote = <ref name="aaa474_2_653" /> |
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| absmag_v = −4.47<ref name=Anderson2012/> {{nowrap|(−4.3, −1.8, −1.7)<ref name=aj127_5_2915/>}} |
| absmag_v = −4.47<ref name="Anderson2012" /> {{nowrap|(−4.3, −1.8, −1.7)<ref name="aj127_5_2915" />}} |
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}} |
}} |
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{{Starbox detail |
{{Starbox detail |
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| component1 = ε Car A |
| component1 = ε Car A |
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| mass = 10.5<ref name=aj127_5_2915/> |
| mass = 10.5<ref name=aj127_5_2915 /> |
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| radius = {{solar radius calculator|type=logLT|1=3.91|logLerr=0.07|2=4460|Terr=90}}<ref name="lithium" />{{efn | name=radius | Applying the [[Stefan–Boltzmann law]] with a nominal [[sun|solar]] [[effective temperature]] of 5,772 [[Kelvin|K]]: |
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:<math>\sqrt{\biggl(\frac{5,772}{4,460}\biggr)^4 \cdot 10^{3.91}} = 151\ R_\odot</math>.}} |
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| metal_fe = |
| metal_fe = |
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| age_myr = {{nowrap|31.2 ± 10.1}}<ref name=mnras410_1_190/> |
| age_myr = {{nowrap|31.2 ± 10.1}}<ref name="mnras410_1_190" /> |
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| luminosity = |
| luminosity = 8,128<ref name="lithium" /> |
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| temperature = |
| temperature = {{val|4460|90|fmt=commas}}<ref name="lithium" /> |
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| rotational_velocity = |
| rotational_velocity = |
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| component2 = ε Car B |
| component2 = ε Car B |
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| mass2 = 7.30<ref name=aj127_5_2915/> |
| mass2 = 7.30<ref name="aj127_5_2915" /> |
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| temperature2 = 20,417<ref name=aj127_5_2915/> |
| temperature2 = 20,417<ref name="aj127_5_2915" /> |
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| radius2 = |
| radius2 = |
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| age_myr2 = 20<ref name=aj127_5_2915/> |
| age_myr2 = 20<ref name="aj127_5_2915" /> |
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}} |
}} |
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{{Starbox catalog |
{{Starbox catalog |
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{{Starbox end}} |
{{Starbox end}} |
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'''Epsilon Carinae''' ('''ε Carinae''', abbreviated '''Epsilon Car''', '''ε Car'''), officially named '''Avior''' {{IPAc-en|'|ei|v|j|@r}}<!--per 'savior', 'havior' & 'pavior' in Webster, and 'saviour', 'pavio(u)r' in the OED, though 'haviour' is /'heivi@r/ in the OED-->,<ref |
'''Epsilon Carinae''' ('''ε Carinae''', abbreviated '''Epsilon Car''', '''ε Car'''), officially named '''Avior''' {{IPAc-en|'|ei|v|j|@r}}<!--per 'savior', 'havior' & 'pavior' in Webster, and 'saviour', 'pavio(u)r' in the OED, though 'haviour' is /'heivi@r/ in the OED-->,<ref>{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt | title=IAU Catalog of Star Names |access-date=28 July 2016}}</ref> is a [[binary star]] in the southern [[constellation]] of [[Carina (constellation)|Carina]]. At [[apparent magnitude]] +1.86 it is [[list of brightest stars|one of the brightest stars]] in the night sky, but is not visible from most of the [[northern hemisphere]]. The [[False Cross]] is an [[asterism (astronomy)|asterism]] formed of [[Delta Velorum]], [[Kappa Velorum]], [[Iota Carinae]] and ε Carinae. It is so called because it is sometimes mistaken for the [[Crux|Southern Cross]], causing errors in [[astronavigation]].<ref>{{cite book|last=Moore|first=Patrick|title=Patrick Moore's Astronomy: Teach Yourself|publisher=Hachette |year=2010|isbn=978-1444129779|url=https://books.google.com/books?id=D7M0Rgc1ONAC&pg=PT127}}</ref> |
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[[File:Avior.png|left|thumb| |
[[File:Avior.png|left|thumb|Celestia simulation of the ε Carinae system]] |
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Epsilon Carinae is located roughly {{Convert|560|-|660|ly|pc|abbr=off|lk=on}} from the [[Sun]].<ref name=aaa474_2_653/> Measurements during the [[Hipparcos]] mission give the pair an [[angular separation]] of 0.46 [[Minute and second of arc|arcseconds]] with a difference in magnitude of 2.0.<ref name=apjss119_1_83/> At their estimated distance, this angle is equivalent to a physical separation of around 4 [[astronomical unit]]s.<ref name=kaler/> |
Epsilon Carinae is located roughly {{Convert|560|-|660|ly|pc|abbr=off|lk=on}} from the [[Sun]].<ref name="aaa474_2_653" /> Measurements during the [[Hipparcos]] mission give the pair an [[angular separation]] of 0.46 [[Minute and second of arc|arcseconds]] with a difference in magnitude of 2.0.<ref name="apjss119_1_83" /> At their estimated distance, this angle is equivalent to a physical separation of around 4 [[astronomical unit]]s.<ref name="kaler" /> |
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⚫ | The primary component has an apparent visual magnitude of 2.2,<ref name="aaa356_141" /> which by itself would still make it the [[List of stars in Carina|third-brightest star]] in the constellation. It is an [[stellar evolution|evolved]] [[giant star]] with a [[stellar classification]] of K0 III. However, examination of the ultraviolet flux from this star suggests it may instead be of spectral type K7.<ref name="apjss119_1_83" /> The fainter secondary companion has an apparent visual magnitude of 4.1,<ref name="aaa356_141" /> which, if it were a solitary star, would be bright enough to be seen with the naked eye. This is a hot, core [[hydrogen]]-fusing [[B-type main sequence star]] of spectral class B2 Vp.<ref name="apjss119_1_83" /> The secondary may itself have an orbiting stellar companion of spectral class F8.<ref name="aj127_5_2915" /> This pair may form an [[eclipsing binary]] system<ref name="kaler" /> with a period of 785 days (2.15 years), resulting in a magnitude change of 0.12 during each eclipse.<ref name="yalebsc" /><ref name="jaavso24_2_105" /> |
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It is one of the most beautiful Star System. |
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guidelines of '''SCBO''' |
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⚫ | The primary component has an apparent visual magnitude of 2.2,<ref name=aaa356_141/> which by itself would still make it the [[List of stars in Carina|third-brightest star]] in the constellation. It is an [[stellar evolution|evolved]] [[giant star]] with a [[stellar classification]] of K0 III. However, examination of the ultraviolet flux from this star suggests it may instead be of spectral type K7.<ref name=apjss119_1_83/> The fainter secondary companion has an apparent visual magnitude of 4.1,<ref name=aaa356_141/> which, if it were a solitary star, would be bright enough to be seen with the naked eye. This is a hot, core [[hydrogen]]-fusing [[B-type main sequence star]] of spectral class B2 Vp.<ref name=apjss119_1_83/> The secondary may itself have an orbiting stellar companion of spectral class F8.<ref name=aj127_5_2915/> This pair may form an [[eclipsing binary]] system<ref name=kaler/> with a period of 785 days (2.15 years), resulting in a magnitude change of 0.12 during each eclipse.<ref name=yalebsc/><ref name=jaavso24_2_105/> |
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==Etymology== |
==Etymology== |
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''ε Carinae'' ([[Latinisation of names|Latinised]] to ''Epsilon Carinae'') is the star's [[Bayer designation]]. |
''ε Carinae'' ([[Latinisation of names|Latinised]] to ''Epsilon Carinae'') is the star's [[Bayer designation]]. |
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The name ''Avior'' is not classical in origin. It was assigned to the star by [[HM Nautical Almanac Office]] in the late 1930s during the creation of The Air Almanac, a navigational almanac for the [[Royal Air Force]]. Of the fifty-seven [[List of selected stars for navigation|navigation star]]s included in the new almanac, two had no classical names: Epsilon Carinae and [[Alpha Pavonis]]. The RAF insisted that all of the stars must have names, so new names were invented. Alpha Pavonis was named "Peacock", a translation of [[Pavo (constellation)|Pavo]], whilst Epsilon Carinae was called "Avior". [[Donald Sadler]], then Superintendent of [[HM Nautical Almanac Office]], recounted this in his memoirs<ref name=sadler/> but failed to explain the etymology of the invented name. In 2016, the [[International Astronomical Union]] organized a [[IAU Working Group on Star Names|Working Group on Star Names]] (WGSN)<ref |
The name ''Avior'' is not classical in origin. It was assigned to the star by [[HM Nautical Almanac Office]] in the late 1930s during the creation of The Air Almanac, a navigational almanac for the [[Royal Air Force]]. Of the fifty-seven [[List of selected stars for navigation|navigation star]]s included in the new almanac, two had no classical names: Epsilon Carinae and [[Alpha Pavonis]]. The RAF insisted that all of the stars must have names, so new names were invented. Alpha Pavonis was named "Peacock", a translation of [[Pavo (constellation)|Pavo]], whilst Epsilon Carinae was called "Avior". [[Donald Sadler]], then Superintendent of [[HM Nautical Almanac Office]], recounted this in his memoirs<ref name="sadler" /> but failed to explain the etymology of the invented name. In 2016, the [[International Astronomical Union]] organized a [[IAU Working Group on Star Names|Working Group on Star Names]] (WGSN)<ref>{{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN)|access-date=22 May 2016}}</ref> to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016<ref>{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/WGSN_bulletin1.pdf | title=Bulletin of the IAU Working Group on Star Names, No. 1 |access-date=28 July 2016}}</ref> included a table of the first two batches of names approved by the WGSN; which included ''Avior'' for this star. |
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In [[Chinese language|Chinese]], {{lang|zh|海石}} ({{lang|zh-Latn|Hǎi Shí}}), meaning ''[[Chinese constellations#The Southern Asterisms (近南極星區)|Sea Rock]]'', refers to an asterism consisting of ε Carinae, [[Iota Carinae]], [[HD 83183]], [[HD 84810]] and [[Upsilon Carinae]] .<ref>{{in lang|zh}} ''中國星座神話'', written by 陳久金. Published by 台灣書房出版有限公司, 2005, {{ISBN|978-986-7332-25-7}}.</ref> Consequently, ε Carinae itself is known as {{lang|zh|海石一}} ({{lang|zh-Latn|Hǎi Shí yī}}, {{lang-en|the First Star of Sea Rock}}.)<ref>{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ama_b.htm 香港太空館 – 研究資源 – 亮星中英對照表] {{webarchive|url=https://web.archive.org/web/20100811014924/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ama_b.htm |date=2010-08-11 |
In [[Chinese language|Chinese]], {{lang|zh|海石}} ({{lang|zh-Latn|Hǎi Shí}}), meaning ''[[Chinese constellations#The Southern Asterisms (近南極星區)|Sea Rock]]'', refers to an asterism consisting of ε Carinae, [[Iota Carinae]], [[HD 83183]], [[HD 84810]] and [[Upsilon Carinae]] .<ref>{{in lang|zh}} ''中國星座神話'', written by 陳久金. Published by 台灣書房出版有限公司, 2005, {{ISBN|978-986-7332-25-7}}.</ref> Consequently, ε Carinae itself is known as {{lang|zh|海石一}} ({{lang|zh-Latn|Hǎi Shí yī}}, {{lang-en|the First Star of Sea Rock}}.)<ref>{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ama_b.htm 香港太空館 – 研究資源 – 亮星中英對照表] {{webarchive|url=https://web.archive.org/web/20100811014924/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ama_b.htm |date=2010-08-11}}, Hong Kong Space Museum. Accessed on line November 23, 2010.</ref> |
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==Notes== |
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{{Notelist}} |
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==References== |
==References== |
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{{reflist|refs= |
{{reflist|refs= |
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<ref name="aaa474_2_653">{{citation | last1=van Leeuwen | first1=F. | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 |date=November 2007 | pages=653–664 | doi=10.1051/0004-6361:20078357 | bibcode=2007A&A...474..653V | arxiv=0708.1752 | s2cid=18759600 | postscript=.}}</ref> |
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<ref name= |
<ref name="Anderson2012">{{citation | title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | s2cid=119257644 | postscript=.}}</ref> |
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<ref name=Anderson2012>{{citation |
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| title=XHIP: An extended hipparcos compilation |
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| last1=Anderson | first1=E. | last2=Francis | first2=Ch. |
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| journal=Astronomy Letters |
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| volume=38 | issue=5 | pages=331 | year=2012 |
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| bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 |
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| arxiv=1108.4971 | s2cid=119257644 | postscript=. }}</ref> |
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⚫ | <ref name=sadler>{{citation | last1=Sadler | first1=D. H. | editor1-last=Wilkins | editor1-first=G. A. | title=A Personal History of H.M. Nautical Almanac Office | url=http://astro.ukho.gov.uk/nao/history/dhs_gaw/nao_perhist_0802_dhs.pdf |
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⚫ | <ref name="sadler">{{citation | last1=Sadler | first1=D. H. | editor1-last=Wilkins | editor1-first=G. A. | title=A Personal History of H.M. Nautical Almanac Office | url=http://astro.ukho.gov.uk/nao/history/dhs_gaw/nao_perhist_0802_dhs.pdf | publisher=Unpublished | location=Sidford, Devon | page=4 | postscript=. | access-date=2012-02-08 | archive-date=2012-04-03 | archive-url=https://web.archive.org/web/20120403214348/http://astro.ukho.gov.uk/nao/history/dhs_gaw/nao_perhist_0802_dhs.pdf | url-status=dead}}</ref> |
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<ref name=apjss119_1_83>{{citation | last1=Parsons | first1=Sidney B. | last2=Ake | first2=Thomas B. | title=Ultraviolet and Optical Studies of Binaries with Luminous Cool Primaries and Hot Companions. V. The Entire IUE Sample | journal=The Astrophysical Journal Supplement Series | volume=119 | issue=1 | pages=83–104 |date=November 1998 | doi=10.1086/313152 | bibcode=1998ApJS..119...83P | postscript=. | doi-access=free }}</ref> |
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<ref name= |
<ref name="apjss119_1_83">{{citation | last1=Parsons | first1=Sidney B. | last2=Ake | first2=Thomas B. | title=Ultraviolet and Optical Studies of Binaries with Luminous Cool Primaries and Hot Companions. V. The Entire IUE Sample | journal=The Astrophysical Journal Supplement Series | volume=119 | issue=1 | pages=83–104 |date=November 1998 | doi=10.1086/313152 | bibcode=1998ApJS..119...83P | postscript=. | doi-access=free}}</ref> |
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<ref name= |
<ref name="houk1978">{{citation | last1=Houk | first1=Nancy | title=Michigan catalogue of two-dimensional spectral types for the HD stars | journal=University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations −90_ to −53_ƒ0 | volume=1 | location=Ann Arbor | publisher=Dept. of Astronomy, University of Michigan | year=1978 | bibcode=1975mcts.book.....H | postscript=.}}</ref> |
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<ref name= |
<ref name="rgcrv">{{citation | last=Evans | first=D. S. | date=June 20–24, 1966 | editor1-last=Batten | editor1-first=Alan Henry | editor2-last=Heard | editor2-first=John Frederick | contribution=The Revision of the General Catalogue of Radial Velocities | title=Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 | volume=30 | page=57 | location=University of Toronto | publisher=[[International Astronomical Union]] | bibcode=1967IAUS...30...57E | postscript=.}}</ref> |
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<ref name= |
<ref name="clpl4_99">{{citation | last1=Johnson | display-authors=1 | first1=H. L. | last2=Iriarte | first2=B. | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z. | title=UBVRIJKL photometry of the bright stars | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | pages=99 | year=1966 | bibcode=1966CoLPL...4...99J | postscript=.}}</ref> |
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<ref name="aaa356_141">{{citation | last1=Fabricius | first1=C. | last2=Makarov | first2=V. V. | title=Two-colour photometry for 9473 components of close Hipparcos double and multiple stars | journal=Astronomy and Astrophysics | volume=356 | pages=141–145 |date=April 2000 | bibcode=2000A&A...356..141F | postscript=.}}</ref> |
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<ref name=jaavso24_2_105>{{citation | last1=Hoffleit | first1=Dorrit | title=A Catalogue of Correlations Between Eclipsing Binaries and Other Categories of Double Stars | journal=The Journal of the American Association of Variable Star Observers | volume=24 | issue=2 | pages=105–116 | year=1996 | bibcode=1996JAVSO..24..105H |
<ref name="jaavso24_2_105">{{citation | last1=Hoffleit | first1=Dorrit | title=A Catalogue of Correlations Between Eclipsing Binaries and Other Categories of Double Stars | journal=The Journal of the American Association of Variable Star Observers | volume=24 | issue=2 | pages=105–116 | year=1996 | bibcode=1996JAVSO..24..105H}}</ref> |
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<ref name=yalebsc>{{citation | last1=Hoffleit | first1=Dorrit | last2=Warren Jr | first2=W. H. | title=The Bright Star Catalogue | edition=5th revised | publisher=Smithsonian Astrophysical Observatory | url=http://tdc-www.harvard.edu/catalogs/bsc5.html | access-date=2012-02-12 | postscript=. |
<ref name="yalebsc">{{citation | last1=Hoffleit | first1=Dorrit | last2=Warren Jr | first2=W. H. | title=The Bright Star Catalogue | edition=5th revised | publisher=Smithsonian Astrophysical Observatory | url=http://tdc-www.harvard.edu/catalogs/bsc5.html | access-date=2012-02-12 | postscript=.}}. See: [http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=V%2F50 VizieR V/50]</ref> |
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<ref name=kaler>{{citation | first1=James B. | last1=Kaler | title=AVIOR (Epsilon Carinae) | work=Stars | publisher=[[University of Illinois]] | url=http://stars.astro.illinois.edu/sow/avior.html | access-date=2012-02-12 | postscript=. |
<ref name="kaler">{{citation | first1=James B. | last1=Kaler | title=AVIOR (Epsilon Carinae) | work=Stars | publisher=[[University of Illinois]] | url=http://stars.astro.illinois.edu/sow/avior.html | access-date=2012-02-12 | postscript=.}}</ref> |
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<ref name=mnras410_1_190>{{citation | last1=Tetzlaff | first1=N. | last2=Neuhäuser | first2=R. | last3=Hohle | first3=M. M. | title=A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume=410 | issue=1 | pages=190–200 |date=January 2011 | doi=10.1111/j.1365-2966.2010.17434.x | bibcode=2011MNRAS.410..190T | postscript=. |arxiv = 1007.4883 | s2cid=118629873 |
<ref name="mnras410_1_190">{{citation | last1=Tetzlaff | first1=N. | last2=Neuhäuser | first2=R. | last3=Hohle | first3=M. M. | title=A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume=410 | issue=1 | pages=190–200 |date=January 2011 | doi=10.1111/j.1365-2966.2010.17434.x | bibcode=2011MNRAS.410..190T | postscript=. |arxiv = 1007.4883 | s2cid=118629873}}</ref> |
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<ref name=aj127_5_2915>{{citation | last1=Parsons | first1=Sidney B. | title=New and Confirmed Triple Systems with Luminous Cool Primaries and Hot Companions | journal=The Astronomical Journal | volume=127 | issue=5 | pages=2915–2930 |date=May 2004 | doi=10.1086/383546 | bibcode=2004AJ....127.2915P | postscript=. | doi-access=free |
<ref name="aj127_5_2915">{{citation | last1=Parsons | first1=Sidney B. | title=New and Confirmed Triple Systems with Luminous Cool Primaries and Hot Companions | journal=The Astronomical Journal | volume=127 | issue=5 | pages=2915–2930 |date=May 2004 | doi=10.1086/383546 | bibcode=2004AJ....127.2915P | postscript=. | doi-access=free}}</ref> |
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<ref name="lithium">{{Citation |last=Charbonnel |first=C. |last2=Lagarde |first2=N. |last3=Jasniewicz |first3=G. |last4=North |first4=P. L. |last5=Shetrone |first5=M. |last6=Krugler Hollek |first6=J. |last7=Smith |first7=V. V. |last8=Smiljanic |first8=R. |last9=Palacios |first9=A. |last10=Ottoni |first10=G. |date=2020-01-01 |title=Lithium in red giant stars: Constraining non-standard mixing with large surveys in the Gaia era |bibcode=2020A&A...633A..34C |journal=Astronomy and Astrophysics |volume=633 |pages=A34 |doi=10.1051/0004-6361/201936360 |issn=0004-6361|arxiv=1910.12732 }} [https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=J/A%2BA/633/A34&HD=71129 Epsilon Carinae's database entry] at [[VizieR]].</ref> |
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}} |
}} |
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Revision as of 22:17, 29 July 2024
Observation data Epoch J2000 Equinox J2000 | |
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Constellation | Carina |
Right ascension | 08h 22m 30.83526s[1] |
Declination | −59° 30′ 34.1431″[1] |
Apparent magnitude (V) | 1.86[2] (2.166/4.121)[3] |
Characteristics | |
Spectral type | K3 III[4] + B2 Vp[5] |
U−B color index | +0.19[2] |
B−V color index | +1.27[2] |
Variable type | Eclipsing (suspected)[6] |
Astrometry | |
Radial velocity (Rv) | +11.6[7] km/s |
Proper motion (μ) | RA: –25.52[1] mas/yr Dec.: 22.72[1] mas/yr |
Parallax (π) | 5.39 ± 0.42 mas[1] |
Distance | 610 ± 50 ly (190 ± 10 pc) |
Absolute magnitude (MV) | −4.47[8] (−4.3, −1.8, −1.7)[9] |
Details | |
ε Car A | |
Mass | 10.5[9] M☉ |
Radius | 151 ± 14[10][a] R☉ |
Luminosity | 8,128[10] L☉ |
Temperature | 4,460±90[10] K |
Age | 31.2 ± 10.1[11] Myr |
ε Car B | |
Mass | 7.30[9] M☉ |
Temperature | 20,417[9] K |
Age | 20[9] Myr |
Other designations | |
A: HD 71129 | |
B: HD 71130 | |
Database references | |
SIMBAD | ε Carinae |
A | |
B |
Epsilon Carinae (ε Carinae, abbreviated Epsilon Car, ε Car), officially named Avior /ˈeɪvjər/,[12] is a binary star in the southern constellation of Carina. At apparent magnitude +1.86 it is one of the brightest stars in the night sky, but is not visible from most of the northern hemisphere. The False Cross is an asterism formed of Delta Velorum, Kappa Velorum, Iota Carinae and ε Carinae. It is so called because it is sometimes mistaken for the Southern Cross, causing errors in astronavigation.[13]
Epsilon Carinae is located roughly 560–660 light-years (170–200 parsecs) from the Sun.[1] Measurements during the Hipparcos mission give the pair an angular separation of 0.46 arcseconds with a difference in magnitude of 2.0.[5] At their estimated distance, this angle is equivalent to a physical separation of around 4 astronomical units.[14]
The primary component has an apparent visual magnitude of 2.2,[3] which by itself would still make it the third-brightest star in the constellation. It is an evolved giant star with a stellar classification of K0 III. However, examination of the ultraviolet flux from this star suggests it may instead be of spectral type K7.[5] The fainter secondary companion has an apparent visual magnitude of 4.1,[3] which, if it were a solitary star, would be bright enough to be seen with the naked eye. This is a hot, core hydrogen-fusing B-type main sequence star of spectral class B2 Vp.[5] The secondary may itself have an orbiting stellar companion of spectral class F8.[9] This pair may form an eclipsing binary system[14] with a period of 785 days (2.15 years), resulting in a magnitude change of 0.12 during each eclipse.[6][15]
Etymology
ε Carinae (Latinised to Epsilon Carinae) is the star's Bayer designation.
The name Avior is not classical in origin. It was assigned to the star by HM Nautical Almanac Office in the late 1930s during the creation of The Air Almanac, a navigational almanac for the Royal Air Force. Of the fifty-seven navigation stars included in the new almanac, two had no classical names: Epsilon Carinae and Alpha Pavonis. The RAF insisted that all of the stars must have names, so new names were invented. Alpha Pavonis was named "Peacock", a translation of Pavo, whilst Epsilon Carinae was called "Avior". Donald Sadler, then Superintendent of HM Nautical Almanac Office, recounted this in his memoirs[16] but failed to explain the etymology of the invented name. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[17] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[18] included a table of the first two batches of names approved by the WGSN; which included Avior for this star.
In Chinese, 海石 (Hǎi Shí), meaning Sea Rock, refers to an asterism consisting of ε Carinae, Iota Carinae, HD 83183, HD 84810 and Upsilon Carinae .[19] Consequently, ε Carinae itself is known as 海石一 (Hǎi Shí yī, English: the First Star of Sea Rock.)[20]
Notes
- ^ Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
- .
References
- ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- ^ a b c Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
- ^ a b c Fabricius, C.; Makarov, V. V. (April 2000), "Two-colour photometry for 9473 components of close Hipparcos double and multiple stars", Astronomy and Astrophysics, 356: 141–145, Bibcode:2000A&A...356..141F.
- ^ Houk, Nancy (1978), "Michigan catalogue of two-dimensional spectral types for the HD stars", University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations −90_ to −53_ƒ0, 1, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1975mcts.book.....H.
- ^ a b c d Parsons, Sidney B.; Ake, Thomas B. (November 1998), "Ultraviolet and Optical Studies of Binaries with Luminous Cool Primaries and Hot Companions. V. The Entire IUE Sample", The Astrophysical Journal Supplement Series, 119 (1): 83–104, Bibcode:1998ApJS..119...83P, doi:10.1086/313152.
- ^ a b Hoffleit, Dorrit; Warren Jr, W. H., The Bright Star Catalogue (5th revised ed.), Smithsonian Astrophysical Observatory, retrieved 2012-02-12.. See: VizieR V/50
- ^ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E.
- ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ a b c d e f Parsons, Sidney B. (May 2004), "New and Confirmed Triple Systems with Luminous Cool Primaries and Hot Companions", The Astronomical Journal, 127 (5): 2915–2930, Bibcode:2004AJ....127.2915P, doi:10.1086/383546.
- ^ a b c Charbonnel, C.; Lagarde, N.; Jasniewicz, G.; North, P. L.; Shetrone, M.; Krugler Hollek, J.; Smith, V. V.; Smiljanic, R.; Palacios, A.; Ottoni, G. (2020-01-01), "Lithium in red giant stars: Constraining non-standard mixing with large surveys in the Gaia era", Astronomy and Astrophysics, 633: A34, arXiv:1910.12732, Bibcode:2020A&A...633A..34C, doi:10.1051/0004-6361/201936360, ISSN 0004-6361 Epsilon Carinae's database entry at VizieR.
- ^ Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.
{{citation}}
: CS1 maint: unflagged free DOI (link) - ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.
- ^ Moore, Patrick (2010). Patrick Moore's Astronomy: Teach Yourself. Hachette. ISBN 978-1444129779.
- ^ a b Kaler, James B., "AVIOR (Epsilon Carinae)", Stars, University of Illinois, retrieved 2012-02-12.
- ^ Hoffleit, Dorrit (1996), "A Catalogue of Correlations Between Eclipsing Binaries and Other Categories of Double Stars", The Journal of the American Association of Variable Star Observers, 24 (2): 105–116, Bibcode:1996JAVSO..24..105H
- ^ Sadler, D. H., Wilkins, G. A. (ed.), A Personal History of H.M. Nautical Almanac Office (PDF), Sidford, Devon: Unpublished, p. 4, archived from the original (PDF) on 2012-04-03, retrieved 2012-02-08.
- ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
- ^ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016.
- ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
- ^ (in Chinese) 香港太空館 – 研究資源 – 亮星中英對照表 Archived 2010-08-11 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.