“RW Cygni”的意思、由来-开放百科全书

RW Cygni is a semiregular variable star in the constellation Cygnus, about a degree east of 2nd magnitude γ Cygni. Its apparent magnitude varies between 8.05 and 9.70 and its spectral type between M2 and M4.

Distance

The Hipparcos parallax for RW Cygni is 0.91 mas but with a very large margin of error.^[2] RW Cygni is assumed to be a member of the Cygnus OB9 Stellar Association and therefore around 3,600 light-years from the solar system.^[4]

Properties

RW Cygni is a red supergiant with a bolometric luminosity around {{solar luminosity|150,000}}.^[5]^[4] Its spectral type is given in the General Catalogue of Variable Stars as M2-4Ia-Iab, and one of the most recent catalogues of MK spectral classifications gives M3-M4Ia-Iab.^[6] The effective temperature is directly calculated to be 3,600 K, giving a radius of {{solar radius|980}}.^[4] An alternate calculation gives a higher temperature of 3,920 K and a correspondingly lower radius of {{solar radius|680}}. Using the more conservative figure, if it was placed at the center of Solar System, it would be extend past the orbit of Mars and into the Asteroid Belt.

The initial mass of RW Cygni has been estimated from its position relative to theoretical stellar evolutionary tracks to be around {{solar mass|20}}. Observations of its atmosphere suggest that it is losing mass at a rate of {{solar mass|{{val|3.2|e=-9}}}} per year.

RW Cygni is classified as a semiregular variable star. It is given the subtype SRc, indicating that it is a cool supergiant.^[1] Its brightness varies from extremes of magnitude +8.0 and +9.5 with a period of 580 ± 80 days. No long secondary period has been detected.^[7]

See also

References

1. ^¹²³{{cite journal|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)|journal=VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S|volume=1|display-authors=etal|author1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}
2. ^¹²³{{cite journal|bibcode=2007A&A...474..653V|title=Validation of the new Hipparcos reduction|journal=Astronomy and Astrophysics|volume=474|issue=2|pages=653|author1=Van Leeuwen|first1=F.|year=2007|doi=10.1051/0004-6361:20078357|arxiv = 0708.1752 }}
3. ^{{cite journal| author =| title =Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters| journal =Astronomy and Astrophysics| year =2005| volume = 405| pages =165| number =| bibcode = 2005A&A...430..165F| author1 =Famaey| first1 =B.| last2 =Jorissen| first2 =A.| last3 =Luri| first3 =X.| last4 =Mayor| first4 =M.| last5 =Udry| first5 =S.| last6 =Dejonghe| first6 =H.| last7 =Turon| first7 =C.| doi =10.1051/0004-6361:20041272|arxiv = astro-ph/0409579 }}
4. ^¹²³⁴{{cite journal| author =| title =The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not As Cool As We Thought| journal =The Astrophysical Journal| year =2005| volume =628| issue =2| pages =973| bibcode = 2005ApJ...628..973L| author1-link = Emily Levesque| author1 =Levesque| first1 =Emily M.| last2 =Massey| first2 =Philip| last3 =Olsen| first3 =K. A. G.| last4 =Plez| first4 =Bertrand| last5 =Josselin| first5 =Eric| last6 =Maeder| first6 =Andre| last7 =Meynet| first7 =Georges| doi =10.1086/430901| arxiv =astro-ph/0504337}}
5. ^¹²{{cite journal|bibcode=2011A&A...526A.156M|title=The mass-loss rates of red supergiants and the de Jager prescription|journal=Astronomy and Astrophysics|volume=526|pages=A156|author1=Mauron|first1=N.|last2=Josselin|first2=E.|year=2011|doi=10.1051/0004-6361/201013993|arxiv = 1010.5369 }}
6. ^{{cite journal|bibcode=1989ApJS...71..245K|title=The Perkins catalog of revised MK types for the cooler stars|journal=Astrophysical Journal Supplement Series|volume=71|pages=245|author1=Keenan|first1=Philip C.|last2=McNeil|first2=Raymond C.|year=1989|doi=10.1086/191373}}
7. ^{{cite journal| author = | title =Variability in red supergiant stars: Pulsations, long secondary periods and convection noise | journal =Monthly Notices of the Royal Astronomical Society | volume =372 | issue =4 | pages =1721 | bibcode = 2006MNRAS.372.1721K | author1 =Kiss | first1 =L. L. | last2 =Szabó | first2 =Gy. M. | last3 =Bedding | first3 =T. R. | year =2006 | doi =10.1111/j.1365-2966.2006.10973.x | arxiv =astro-ph/0608438}}

词条	RW Cygni
释义	Distance Properties See also References {{Starbox begin \| name = RW Cygni }}{{Starbox image \| image= \| caption=Region around γ Cygni, with RW Cygni annotated on the full-size image (north is right) \| credit= }}{{Starbox observe \| epoch=J2000 \| ra={{RA\|20\|28\|50.59095}}^[1] \| dec={{DEC\|39\|58\|54.4268}}^[1] \| appmag_v={{nowrap\|8.05 - 9.70^[3]}} \| constell=Cygnus }}{{Starbox character \| class=M2-4Ia-Iab^[1] \| b-v= \| u-b= \| variable=SRc^[1] }}{{Starbox astrometry \| radial_v= \| prop_mo_ra= \| prop_mo_dec= \| parallax=0.91 \| p_error=1.03 \| parallax_footnote=^[2] \| dist_pc= \| dist_ly=~3,600^[3] \| absmag_v=-6.41^[4] }}{{Starbox detail \| radius=680 - 980^[4] \| luminosity = 145,000^[5]–156,000 \| temperature=3,600^[5]-3,920 \| metal= \| rotation= \| gravity= \| age= }}{{Starbox catalogue \| names = {{odlist\|V=RW Cyg\|HIP=101023\|BD=+39 4208\|IRAS=20270+3948\|2MASS=J20285059+3958543}} }}{{ Starbox reference \| Simbad = RW+Cygni }}{{Starbox end}} RW Cygni is a semiregular variable star in the constellation Cygnus, about a degree east of 2nd magnitude γ Cygni. Its apparent magnitude varies between 8.05 and 9.70 and its spectral type between M2 and M4. Distance The Hipparcos parallax for RW Cygni is 0.91 mas but with a very large margin of error.^[2] RW Cygni is assumed to be a member of the Cygnus OB9 Stellar Association and therefore around 3,600 light-years from the solar system.^[4] Properties RW Cygni is a red supergiant with a bolometric luminosity around {{solar luminosity\|150,000}}.^[5]^[4] Its spectral type is given in the General Catalogue of Variable Stars as M2-4Ia-Iab, and one of the most recent catalogues of MK spectral classifications gives M3-M4Ia-Iab.^[6] The effective temperature is directly calculated to be 3,600 K, giving a radius of {{solar radius\|980}}.^[4] An alternate calculation gives a higher temperature of 3,920 K and a correspondingly lower radius of {{solar radius\|680}}. Using the more conservative figure, if it was placed at the center of Solar System, it would be extend past the orbit of Mars and into the Asteroid Belt. The initial mass of RW Cygni has been estimated from its position relative to theoretical stellar evolutionary tracks to be around {{solar mass\|20}}. Observations of its atmosphere suggest that it is losing mass at a rate of {{solar mass\|{{val\|3.2\|e=-9}}}} per year. RW Cygni is classified as a semiregular variable star. It is given the subtype SRc, indicating that it is a cool supergiant.^[1] Its brightness varies from extremes of magnitude +8.0 and +9.5 with a period of 580 ± 80 days. No long secondary period has been detected.^[7] See also BC Cygni BI Cygni NML Cygni KY Cygni List of largest stars References 1. ^¹²³{{cite journal\|bibcode=2009yCat....102025S\|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)\|journal=VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S\|volume=1\|display-authors=etal\|author1=Samus\|first1=N. N.\|last2=Durlevich\|first2=O. V.\|year=2009}} 2. ^¹²³{{cite journal\|bibcode=2007A&A...474..653V\|title=Validation of the new Hipparcos reduction\|journal=Astronomy and Astrophysics\|volume=474\|issue=2\|pages=653\|author1=Van Leeuwen\|first1=F.\|year=2007\|doi=10.1051/0004-6361:20078357\|arxiv = 0708.1752 }} 3. ^{{cite journal\| author =\| title =Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters\| journal =Astronomy and Astrophysics\| year =2005\| volume = 405\| pages =165\| number =\| bibcode = 2005A&A...430..165F\| author1 =Famaey\| first1 =B.\| last2 =Jorissen\| first2 =A.\| last3 =Luri\| first3 =X.\| last4 =Mayor\| first4 =M.\| last5 =Udry\| first5 =S.\| last6 =Dejonghe\| first6 =H.\| last7 =Turon\| first7 =C.\| doi =10.1051/0004-6361:20041272\|arxiv = astro-ph/0409579 }} 4. ^¹²³⁴{{cite journal\| author =\| title =The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not As Cool As We Thought\| journal =The Astrophysical Journal\| year =2005\| volume =628\| issue =2\| pages =973\| bibcode = 2005ApJ...628..973L\| author1-link = Emily Levesque\| author1 =Levesque\| first1 =Emily M.\| last2 =Massey\| first2 =Philip\| last3 =Olsen\| first3 =K. A. G.\| last4 =Plez\| first4 =Bertrand\| last5 =Josselin\| first5 =Eric\| last6 =Maeder\| first6 =Andre\| last7 =Meynet\| first7 =Georges\| doi =10.1086/430901\| arxiv =astro-ph/0504337}} 5. ^¹²{{cite journal\|bibcode=2011A&A...526A.156M\|title=The mass-loss rates of red supergiants and the de Jager prescription\|journal=Astronomy and Astrophysics\|volume=526\|pages=A156\|author1=Mauron\|first1=N.\|last2=Josselin\|first2=E.\|year=2011\|doi=10.1051/0004-6361/201013993\|arxiv = 1010.5369 }} 6. ^{{cite journal\|bibcode=1989ApJS...71..245K\|title=The Perkins catalog of revised MK types for the cooler stars\|journal=Astrophysical Journal Supplement Series\|volume=71\|pages=245\|author1=Keenan\|first1=Philip C.\|last2=McNeil\|first2=Raymond C.\|year=1989\|doi=10.1086/191373}} 7. ^{{cite journal\| author = \| title =Variability in red supergiant stars: Pulsations, long secondary periods and convection noise \| journal =Monthly Notices of the Royal Astronomical Society \| volume =372 \| issue =4 \| pages =1721 \| bibcode = 2006MNRAS.372.1721K \| author1 =Kiss \| first1 =L. L. \| last2 =Szabó \| first2 =Gy. M. \| last3 =Bedding \| first3 =T. R. \| year =2006 \| doi =10.1111/j.1365-2966.2006.10973.x \| arxiv =astro-ph/0608438}} }}{{Stars of Cygnus}} 8 : M-type supergiants\|Hipparcos objects\|Semiregular variable stars\|Cygnus (constellation)\|Durchmusterung objects\|Objects with variable star designations\|IRAS catalogue objects\|2MASS objects
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