W Cygni

{{short description|Semi-regular variable star in the constellation Cygnus}}

{{Starbox begin

| name = W Cygni

}}

{{Starbox image

| image=

{{Location mark

|image=Cygnus constellation map.svg|alt=|float=center|width=300

|label=|position=right

|mark=Red circle.svg|mark_width=8|mark_link=W Cyg

|x=118|y=259

}}

|caption=Location of W Cygni (circled)

}}

{{Starbox observe

| epoch = J2000.0

| constell = Cygnus

| ra = {{RA|21|36|02.49619}}

| dec = {{DEC|+44|22|28.5292}}

| appmag_v = {{nowrap|5.10 - 6.83}}

}}

{{Starbox character

| class = M4e-M6e(Tc:)III

| b-v = +1.59

| u-b = +1.24

| variable=SRb

}}

{{Starbox astrometry

| radial_v = −12.87

| prop_mo_ra = {{nowrap|65.17 ± 0.42}}

| prop_mo_dec = {{nowrap|1.74 ± 0.30}}

| parallax = 5.72

| p_error = 0.38

| parallax_footnote =

| absmag_v =−0.43

}}

{{Starbox detail

| mass = 0.98

| radius = 227

| luminosity = 5,888

| temperature = 3,373

| metal_fe =

| gravity =

| rotational_velocity =

| age =

}}

{{Starbox catalog

| names = {{odlist | V=W Cyg | HR=8262 | HD=205730 | BD=+44°3877 | HIP=106642 }}

}}

{{Starbox reference

| Simbad = W+Cygni

}}

W Cygni is a semi-regular variable star in the constellation Cygnus, located 570 light-years from Earth. It lies less than half a degree southeast of ρ Cygni. W Cygni is, at times, a naked eye star but it was not given a Bayer or Flamsteed designation. It has been proposed as a binary star system with a hotter main sequence companion, but this has not been confirmed.

File:W Cygni light curve.png

W Cygni was discovered to be variable by John Ellard Gore, and first published in 1885. It has a maximum magnitude of 5.10 and a minimum magnitude 6.83. The star is catalogued as having a primary period of 131.7 days, but shows variations with a variety of periods around 131 days as well as 234 days. It is believed to be pulsating in the first overtone. There is some evidence of additional very slow and small variations in the light curve on a time scale of 3,000–5,000 days.

This star is an aging red giant on the asymptotic giant branch (AGB). Its spectral type ranges between M4e and M6e, and it shows possible elevated levels of Technetium. The masses of AGB stars are poorly known, but using the pulsation properties of W Cygni, it mass is calculated to be slightly less than the sun's. It has expanded to 227 times the girth of the Sun and is radiating 5,888 times the Sun's luminosity from its swollen photosphere at an effective temperature of 3,373 K.

References

{{reflist|refs=

{{cite journal

| title=Further Studies of the Photometric Variability of Bright Pulsating Red Giants

| last1=Percy | first1=John R. | last2=Mashintsova | first2=M.

| last3=Nasui | first3=C. O. | last4=Palaniappan | first4=R.

| last5=Seneviratne | first5=R. | last6=Henry | first6=Gregory W.

| journal=Publications of the Astronomical Society of the Pacific

| volume=120 | issue=867 | page=523 | date=May 2008

| doi=10.1086/588612 | bibcode=2008PASP..120..523P | s2cid=123722836 | doi-access=free }}

{{cite journal|bibcode=2009A&A...498..627F|title=Spectroscopic binaries among Hipparcos M giants,. I. Data, orbits, and intrinsic variations|journal=Astronomy and Astrophysics|volume=498|issue=2|pages=627|last1=Famaey|first1=B.|last2=Pourbaix|first2=D.|last3=Frankowski|first3=A.|last4=Van Eck|first4=S.|last5=Mayor|first5=M.|last6=Udry|first6=S.|last7=Jorissen|first7=A.|year=2009|doi=10.1051/0004-6361/200810698|arxiv = 0901.0934 |s2cid=18739721}}

{{citation

| title=Mg II chromospheric radiative loss rates in cool active and quiet stars

| last1=Cardini | first1=D. | postscript=.

| journal=Astronomy and Astrophysics

| volume=430 | pages=303–311 | date=January 2005

| doi=10.1051/0004-6361:20041440 | bibcode=2005A&A...430..303C |arxiv = astro-ph/0409683 | s2cid=12136256 }}

{{cite journal|bibcode=2016MNRAS.461.3036O|arxiv=1606.09086|title=Ultraviolet emission from main-sequence companions of AGB stars|journal=Monthly Notices of the Royal Astronomical Society|volume=461|issue=3|pages=3036|last1=Ortiz|first1=Roberto|last2=Guerrero|first2=Martín A.|year=2016|doi=10.1093/mnras/stw1547|doi-access=free |s2cid=118619933}}

{{cite journal|bibcode=2007MNRAS.378.1543G|arxiv=0704.3150|title=Semiregular variables in the solar neighbourhood|journal=Monthly Notices of the Royal Astronomical Society|volume=378|issue=4|pages=1543–1549|last1=Glass|first1=I. S.|last2=Van Leeuwen|first2=F.|year=2007|doi=10.1111/j.1365-2966.2007.11903.x|doi-access=free |s2cid=14332208}}

{{cite journal|bibcode=2013JBAA..123...85S|arxiv=1203.6467|title=John Ellard Gore: Of immensity and minuteness|volume= 123|last1=Shears|first1=Jeremy|journal=Journal of the British Astronomical Association|year=2012|page=85}}

{{cite journal|bibcode=2011ARep...55...31S|title=Search for and study of hot circumstellar dust envelopes|journal=Astronomy Reports|volume=55|pages=31–81|last1=Shenavrin|first1=V. I.|last2=Taranova|first2=O. G.|last3=Nadzhip|first3=A. E.|year=2011|issue=1|doi=10.1134/S1063772911010070|s2cid=122700080}}

{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=10926 |title=W Cygni |date=10 July 2017|work=AAVSO Website|publisher=American Association of Variable Star Observers|access-date=31 December 2013}}

{{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|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}

{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|pages=0|last1=Ducati|first1=J. R.|year=2002}}

{{R:Van Leeuwen 2007 Validation of the new Hipparcos reduction}} [http://vizier.u-strasbg.fr/viz-bin/VizieR-S?HIP%106642 Vizier catalog entry]

{{cite journal|bibcode=2013PASJ...65...60T|title=A Method to Estimate the Masses of Asymptotic Giant Branch Variable Stars|journal=Publications of the Astronomical Society of Japan|volume=65|issue=3|pages=60|last1=Takeuti|first1=Mine|last2=Nakagawa|first2=Akiharu|last3=Kurayama|first3=Tomoharu|last4=Honma|first4=Mareki|year=2013|doi=10.1093/pasj/65.3.60|doi-access=free}}

}}

Category:M-type giants

Category:Emission-line stars

Category:Asymptotic-giant-branch stars

Category:Semiregular variable stars

Category:Cygnus (constellation)

Category:Durchmusterung objects