V923 Aquilae
 A photoelectric (yellow)light curvefor V923 Aquilae, plotted from data presented by Lynds (1960).[1]The length of a full phase cycle is 0.8518 days. | |
| Observation data EpochJ2000EquinoxJ2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h30m33.12199s[2] |
| Declination | +03° 26′ 39.8583″[2] |
| Apparent magnitude(V) | 6.06[3] 5.98 to 6.18[4] |
| Characteristics | |
| Evolutionary stage | Main sequence[5] |
| Spectral type | B7III[6] |
| U−Bcolor index | −0.31[3] |
| B−Vcolor index | −0.019±0.008[7] |
| Variable type | Be star[4] |
| Astrometry | |
| Radial velocity(Rv) | −26.0±7.4[7]km/s |
| Proper motion(μ) | RA:11.717[2]mas/yr Dec.:3.089[2]mas/yr |
| Parallax(π) | 3.6705 ± 0.0607mas[2] |
| Distance | 890 ± 10ly (272 ± 5pc) |
| Absolute magnitude(MV) | −0.87[7] |
| Details[5] | |
| Primary | |
| Mass | 6.2±0.3M☉ |
| Luminosity | 1517+158 −143L☉ |
| Surface gravity(logg) | 3.64±0.21cgs |
| Temperature | 16,580±400K |
| Rotational velocity(vsini) | 275±17km/s |
| Secondary | |
| Mass | ~0.5M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
V923 Aquilaeis avariablebinary star[9]system in theequatorialconstellationofAquila.It has the designation HD 183656 from theHenry Draper Catalogue;V932 Aql is thevariable star designation.The system is dimly visible to the naked eye with anapparent visual magnitudethat fluctuates around 6.06.[3]It is located at a distance of approximately 890light yearsfrom theSunbased onparallax,[2]but is drifting closer with aradial velocityof around −26 km/s.[7]
This system was first identified as a likelyspectroscopic binarybyW. E. Harperin 1937, who noted it showed "narrow intense lines of peculiar spectrum".[10]P. W. MerrillandC. G. Burwellidentified it as ashell starin 1949.[11][12]Merrill andA. L. Lowenshowed in 1953 that the shell displayed large radial velocity variations.[13]A photometric study byC. R. Lyndsin 1960 showed the system varied in brightness with an amplitude of more than 0.1 in magnitude and a characteristic period of 0.85 days, although it does not behave periodically over long time intervals.[1]
A more thorough investigation by P. Koubský and associates in 1989 using long-term radial velocity measurements determined this is a spectroscopic binary with anorbital periodof 214.75 days. There is also an overlaying long-term cyclical variation of changing amplitude and period. The modelled binary system shows a primary with a class of around B5–7e and a low mass secondary separated by around 250 times the radius of the Sun (250R☉). They hypothesized that the long-term variation was due to an envelope created by a mass transfer from the secondary component to the primary.[14]However, the mass transfer concept was later brought into question and remains unverified as of 2004.[9]
References
[edit]- ^abLynds, C. R. (March 1960), "The Light-Variations of HD 183656",Astrophysical Journal,131:390,Bibcode:1960ApJ...131..390L,doi:10.1086/146842.
- ^abcdefBrown, A. G. A.;et al. (Gaia collaboration) (August 2018)."GaiaData Release 2: Summary of the contents and survey properties ".Astronomy & Astrophysics.616.A1.arXiv:1804.09365.Bibcode:2018A&A...616A...1G.doi:10.1051/0004-6361/201833051.Gaia DR2 record for this sourceatVizieR.
- ^abcHaupt, H. F.; Schroll, A. (1974), "Photoelektrische Photometrie von Shell-Sternen",Astronomy and Astrophysics Supplement Series,15:311,Bibcode:1974A&AS...15..311H.
- ^abSamus', N. N; et al. (2017). "General catalogue of variable stars".Astronomy Reports.GCVS 5.1.61(1): 80.Bibcode:2017ARep...61...80S.doi:10.1134/S1063772917010085.S2CID125853869.
- ^abZorec, J.; et al. (November 2016), "Critical study of the distribution of rotational velocities of Be stars. I. Deconvolution methods, effects due to gravity darkening, macroturbulence, and binarity",Astronomy & Astrophysics,595:26,Bibcode:2016A&A...595A.132Z,doi:10.1051/0004-6361/201628760,hdl:11336/37946.
- ^Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars",Michigan Spectral Survey,5,Bibcode:1999MSS...C05....0H.
- ^abcdAnderson, 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,S2CID119257644.
- ^"HD 183656".SIMBAD.Centre de données astronomiques de Strasbourg.Retrieved2021-02-21.
{{cite web}}:CS1 maint: postscript (link) - ^abArias, M. L.; et al. (April 2004), "The circumstellar environment of the star V923 Aquilae",Astronomy and Astrophysics,417(2): 679–688,Bibcode:2004A&A...417..679A,doi:10.1051/0004-6361:20034435,hdl:11336/37035.
- ^Harper, W. E. (1937), "The radial velocities of 917 stars",Publications of the Dominion Astrophysical Observatory Victoria,7:1–97,Bibcode:1937PDAO....7....1H.
- ^Merrill, Paul W.; Burwell, Cora G. (November 1949), "Second Supplement to the Mount Wilson Catalogue and Bibliography of Stars of Classes B and a whose Spectra have Bright Hydrogen Lines",Astrophysical Journal,110:387,Bibcode:1949ApJ...110..387M,doi:10.1086/145215.
- ^Bidelman, W. P. (April 1950), "The Spectrum of HR 7415",Publications of the Astronomical Society of the Pacific,62(364): 48,Bibcode:1950PASP...62...48B,doi:10.1086/126224,S2CID119744604.
- ^Merrill, Paul W.; Lowen, A. Louise (July 1953), "Intercomparison of Shell Spectra",Astrophysical Journal,118:18,Bibcode:1953ApJ...118...18M,doi:10.1086/145723.
- ^Koubský, P.; et al. (February 1989), "Properties and Nature of Be Stars. 13. Radial-Velocity Variations of the Shell Star V 923 AQL (HD 183 656) In the Past Sixty Years",Bulletin of the Astronomical Institute of Czechoslovakia,40:31,Bibcode:1989BAICz..40...31K.
