BC Cygni

BC Cygni (afgekort as BC Cyg), ook bekend as HIP 100404 en BD + 37 3903, is 'n rooisuperreus en pulserende veranderlike ster van spektraaltipe M3,5Ia in die sterrebeeld Swaan.

BC Cygni
BC Cygni is as 'n rooi ster te sien (omsirkel). Die helder ster in die middel is γ Cygni. Noord is regs. (Foto: Erik Larsen)
Sterrebeeld	Swaan
Spektraaltipe	M3,5 Ia[1] (M2-M5[2])
Waarnemingsdata (Epog J2000)
Regte klimming	20h 21m 38.55s
Deklinasie	37° 31′ 58.9″
Skynmagnitude (m)	9-10,8[3]
Absolute magnitude (M)	-7,71[4]
B-V-kleurindeks	+3,13 - +3,21[2]
Besonderhede
Massa (M☉)	19
Radius (R☉)	1 031[5]
Ligsterkte (L☉)	204 000[6]
Temperatuur (K)	3 605[7]
Afstand (ligjaar)	5 000
Eienskappe
Veranderlikheid	Halfgereeld (SRc)[1]
Ander name
BC Cyg, HIP 100404, HV 3339, BD+37°3903, IRAS 20197+3722, 2MASS J20213855+3731589[8]
Portaal    Sterrekunde

Dit word beskou as deel van die Cygnus-OB1-assosiasie en lê binne die oop sterreswerm Berkeley 87.^[9] Dit beteken dit is sowat 5 000 ligjare van die Son af.^[10] Dit lê minder as 'n graad noord van 'n ander veranderlike rooisuperreus, BI Cygni.

BC Cygni se berekende effektiewe temperatuur wissel van 2 858 tot 3 614 K tussen 'n ligsterkte van 112 000 tot 145 000 keer dié van die Son. Sy grootte in sy helderste en koelste fase is bereken op sowat 1 553 R_☉ in vergelyking met sy grootte op sy dofste en warmste fase van 856 R_☉. BC Cygni is een van die grootste bekende sterre. As dit in die plek van die Son geplaas sou word, sou dit tot anderkant Jupiter se wentelbaan gestrek het as hy op sy maksimum radius van 1 553 R_☉ was. Met sy massa van sowat 19 M_☉, word bereken dat sy massaverlies sowat 3,2×10⁻⁹ M_☉ per jaar is.^[11]

BC Cyg se helderheid wissel tussen skynbare magnitudes 9 en 10,8 met 'n pulseringstydperk van 720 ± 40 dae.^[3] Tussen omstreeks 1900 en die jaar 2000 het sy gemiddelde helderheid met omtrent 0,5 magnitudes toegeneem.^[2]

Verwysings

1. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
2. Turner, David G.; Rohanizadegan, Mina; Berdnikov, Leonid N.; Pastukhova, Elena N. (2006). "The Long-Term Behavior of the Semiregular M Supergiant Variable BC Cygni". The Publications of the Astronomical Society of the Pacific. 118 (849): 1533. Bibcode:2006PASP..118.1533T. doi:10.1086/508905.
3. Kiss, L. L.; Szabó, Gy. M.; Bedding, T. R. (2006). "Variability in red supergiant stars: Pulsations, long secondary periods and convection noise". Monthly Notices of the Royal Astronomical Society. 372 (4): 1721–1734. arXiv:astro-ph/0608438. Bibcode:2006MNRAS.372.1721K. doi:10.1111/j.1365-2966.2006.10973.x. S2CID 5203133.
4. Levesque, Emily M.; Massey, Philip; Olsen, K. A. G.; Plez, Bertrand; Josselin, Eric; Maeder, Andre; Meynet, Georges (2005). "The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not As Cool As We Thought". The Astrophysical Journal. 628 (2): 973–985. arXiv:astro-ph/0504337. Bibcode:2005ApJ...628..973L. doi:10.1086/430901. S2CID 15109583.
5. Comerón, F.; Djupvik, A. A.; Schneider, N.; Pasquali, A. (Oktober 2020). "The historical record of massive star formation in Cygnus". Astronomy & Astrophysics. 2009: A62. arXiv:2009.12779. Bibcode:2020A&A...644A..62C. doi:10.1051/0004-6361/202039188. S2CID 221970180.
6. Davies, Ben; Beasor, Emma R. (Maart 2020). "The 'red supergiant problem': the upper luminosity boundary of Type II supernova progenitors". MNRAS (in Engels). 493 (1): 468–476. arXiv:2001.06020. Bibcode:2020MNRAS.493..468D. doi:10.1093/mnras/staa174. S2CID 210714093.
7. Messineo, M.; Brown, A. G. A. (2019). "A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2". The Astronomical Journal. 158 (1): 20. arXiv:1905.03744. Bibcode:2019AJ....158...20M. doi:10.3847/1538-3881/ab1cbd. S2CID 148571616.
8. "BC Cygni", SIMBAD (Centre de Données astronomiques de Strasbourg), https://simbad.cds.unistra.fr/simbad/sim-id?Ident=BC+Cygni, besoek op 2023-07-06
9. Sokal, Kimberly R.; Skinner, Stephen L.; Zhekov, Svetozar A.; Güdel, Manuel; Schmutz, Werner (2010). "Chandra Detects the Rare Oxygen-type Wolf-Rayet Star WR 142 and OB Stars in Berkeley 87". The Astrophysical Journal. 715 (2): 1327. arXiv:1004.0462. Bibcode:2010ApJ...715.1327S. doi:10.1088/0004-637X/715/2/1327. S2CID 119232391.
10. de la Fuente, Diego; Román-Zúñiga, Carlos G.; Jiménez-Bailón, Elena; Alves, João; Garcia, Miriam; Venus, Sean (2021). "Clustered star formation toward Berkeley 87/ON2. I. Multiwavelength census and the population overlap problem". Astronomy and Astrophysics. 650: A156. arXiv:2103.06062. Bibcode:2021A&A...650A.156D. doi:10.1051/0004-6361/202040065. S2CID 232170603.
11. Josselin, E.; Plez, B. (2007). "Atmospheric dynamics and the mass loss process in red supergiant stars". Astronomy and Astrophysics. 469 (2): 671. arXiv:0705.0266. Bibcode:2007A&A...469..671J. doi:10.1051/0004-6361:20066353. S2CID 17789027.

Skakels

• Hierdie artikel is in sy geheel of gedeeltelik uit die Engelse Wikipedia vertaal.