Astronomy:CG Cygni
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Short description: Eclipsing ternary star system in constellation Cygnus
Coordinates: 
20h 58m 13.4534s, +35° 10′ 29.6642″
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 58m 13.4534s[2] |
| Declination | +35° 10′ 29.6642″[2] |
| Characteristics | |
| BD+34 4217A | |
| Evolutionary stage | main-sequence star[3] |
| Spectral type | G9+K3[3] |
| Apparent magnitude (g) | 10.06[4] |
| Variable type | RS Canum Venaticorum variable |
| BD+34 4217B | |
| Apparent magnitude (g) | 11.74[5] |
| Astrometry | |
| BD+34 4217A | |
| Proper motion (μ) | RA: 6.638±0.014[4] mas/yr Dec.: −13.87±0.02[4] mas/yr |
| Parallax (π) | 10.2393 ± 0.0170[4] mas |
| Distance | 318.5 ± 0.5 ly (97.7 ± 0.2 pc) |
| BD+34 4217B | |
| Proper motion (μ) | RA: 9.86±0.05 mas/yr Dec.: -16.32±0.06 mas/yr |
| Parallax (π) | 10.2046 ± 0.0391[5] mas |
| Distance | 320 ± 1 ly (98.0 ± 0.4 pc) |
| Orbit | |
| Primary | BD+34 4217Aa |
| Companion | BD+34 4217Ab |
| Period (P) | 0.6311 d[6] |
| Inclination (i) | 82.602±0.099[7]° |
| Details | |
| BD+34 4217Aa | |
| Mass | 0.97[7] M☉ |
| Radius | 0.893[8] R☉ |
| Temperature | 5200[3] K |
| BD+34 4217Ab | |
| Mass | 0.80[7] M☉ |
| Radius | 0.838[8] R☉ |
| Temperature | 4400[3] K |
| Other designations | |
2MASS J20581343+3510298, HIP 103505, GSC 02696-02945, BD+34 4217, Gaia DR2 1866704219781935360 | |
| BD+34 4217A: CG Cyg A, TYC 2696-2945-1, Gaia EDR3 1866704219781935360 | |
| BD+34 4217B: CG Cyg B, TYC 2696-2945-2, Gaia EDR3 1866704219775706624 | |
| Database references | |
| SIMBAD | data |
CG Cygni is a ternary star system composed of main-sequence stars in the constellation of Cygnus about 320 light years away.
System
The star CG Cygni A (BD+34 4217A) itself is a close binary system with ongoing mass transfer between components. The orbital period of the binary is currently increasing. An additional third body (either star or planet) was suspected to exist in the system with an orbital period of 15.9-51 years, creating cyclic period variations of the binary.[6] It was finally confirmed as the star CG Cygni B (BD+34 4217B) in 2020, at a 1.16 arcsecond separation from the primary.[9]
Properties
The primary, BD+34 4217Aa, has a large number of starspots covering up to 18% of its surface.[3] These are located in low latitudes, usually perpendicular to the line connecting the stars Aa and Ab, although reversal of the starspots positions was detected in 1991,[10] 2003[3] and 2008.[11]
References
- ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html.
- ↑ 2.0 2.1 "V* CG Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V%2A+CG+Cyg.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Kozhevnikova, A. V.; Alekseev, I. Yu.; Kozhevnikov, V. P.; Svechnikov, M. A. (2005), "Long-Term Starspot Activity of the Eclipsing Variable System CG Cyg", Astrophysics 48 (3): 291–303, doi:10.1007/s10511-005-0028-1, Bibcode: 2005Ap.....48..291K
- ↑ 4.0 4.1 4.2 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 5.0 5.1 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 6.0 6.1 Shi, Xiao-Min; Xiang, Fu-Yuan; Lu, Ye (2012), "Orbital Period Investigation of the RS CVN-Type Binary CG Cygni", Publications of the Astronomical Society of Japan 64 (6): 121, doi:10.1093/pasj/64.6.121, Bibcode: 2012PASJ...64..121S
- ↑ 7.0 7.1 7.2 Afşar, M.; Heckert, P. A.; i̇Banoǧlu, C. (2004), "Long-term luminosity variations and period changes in CG Cygni", Astronomy & Astrophysics 420 (2): 595–604, doi:10.1051/0004-6361:20040115, Bibcode: 2004A&A...420..595A
- ↑ 8.0 8.1 Korda, D.; Zasche, P.; Wolf, M.; Kučáková, H.; Hoňková, K.; Vraštil, J. (2017), "Photometric Study of Fourteen Low-mass Binaries", The Astronomical Journal 154 (1): 30, doi:10.3847/1538-3881/aa7138, Bibcode: 2017AJ....154...30K
- ↑ Laos, Stefan; Stassun, Keivan G.; Mathieu, Robert D. (2020), "Assessing Spectroscopic Binary Multiplicity Properties Using Robo-AO Imaging", The Astrophysical Journal 902 (2): 107, doi:10.3847/1538-4357/abb3fe, Bibcode: 2020ApJ...902..107L
- ↑ Heckert, P.A.; Zilik, M. (1991), "1991 V Photometry of CG Cyg and a Possible New Variable", Information Bulletin on Variable Stars 3688: 1, Bibcode: 1991IBVS.3688....1H
- ↑ Kozhevnikova, A. V.; Kozhevnikov, V. P.; Alekseev, I. Yu.; Yushkov, I. A.; Dorogov, A. A. (2012), "Spot activity of the binary CG Cyg: Observations during maximum spottedness", Astronomy Reports 56 (4): 281–289, doi:10.1134/S1063772912030043, Bibcode: 2012ARep...56..281K
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