V923 Aquilae
File:V923AqlLightCurve.png A photoelectric (yellow) light curve for V923 Aquilae, plotted from data presented by Lynds (1960).[1] The length of a full phase cycle is 0.8518 days. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | Template:RA[2] |
| Declination | Template:DEC[2] |
| Apparent magnitude (V) | 6.06[3] 5.98 to 6.18[4] |
| Characteristics | |
| Evolutionary stage | Main sequence[5] |
| Spectral type | B7III[6] |
| U−B Template:Engvar | −0.31[3] |
| B−V Template:Engvar | Script error: No such module "val".[7] |
| Variable type | Be star[4] |
| Astrometry | |
| Radial velocity (Rv) | Script error: No such module "val".[7] km/s |
| Proper motion (μ) | RA: 11.717[2] mas/yr Dec.: 3.089[2] mas/yr |
| Parallax (π) | 3.6705±0.0607 mas[2] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | −0.87[7] |
| Details[5] | |
| Primary | |
| Mass | Script error: No such module "val". Template:Solar mass |
| Luminosity | Script error: No such module "val". Template:Solar luminosity |
| Surface gravity (log g) | Script error: No such module "val". cgs |
| Temperature | Script error: No such module "val". K |
| Rotational velocity (v sin i) | Script error: No such module "val". km/s |
| Secondary | |
| Mass | ~0.5 Template:Solar mass |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| Template:Odlist[8] | |
| Database references | |
| SIMBAD | data |
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V923 Aquilae is a variable binary star[9] system in the equatorial constellation of Aquila. It has the designation HD 183656 from the Henry Draper Catalogue; V932 Aql is the variable star designation. The system is dimly visible to the naked eye with an apparent visual magnitude that fluctuates around 6.06.[3] It is located at a distance of approximately 890 light years from the Sun based on parallax,[2] but is drifting closer with a radial velocity of around −26 km/s.[7]
This system was first identified as a likely spectroscopic binary by W. E. Harper in 1937, who noted it showed "narrow intense lines of peculiar spectrum".[10] P. W. Merrill and C. G. Burwell identified it as a shell star in 1949.[11][12] Merrill and A. L. Lowen showed in 1953 that the shell displayed large radial velocity variations.[13] A photometric study by C. R. Lynds in 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 an orbital period of 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 (Script error: No such module "val".). 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
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- ↑ a b Script error: No such module "citation/CS1".
- ↑ a b c d e f Template:Cite Gaia DR2
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- ↑ a b c d Script error: No such module "citation/CS1".
- ↑ Template:Cite simbad
- ↑ a b Script error: No such module "citation/CS1".
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- ↑ Script error: No such module "citation/CS1".
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