CG Cygni

CG Cygni

A light curve for CG Cygni, plotted from TESS data
Observation data
Epoch J2000      Equinox ICRS
Constellation Cygnus
Right ascension 20h 58m 13.4534s
Declination +35° 10′ 29.6642″
Characteristics
BD+34 4217A
Evolutionary stage main-sequence star
Spectral type G9+K3
Apparent magnitude (g) 10.06
Variable type RS Canum Venaticorum variable
BD+34 4217B
Apparent magnitude (g) 11.74
Astrometry
BD+34 4217A
Proper motion (μ) RA: 6.638±0.014 mas/yr
Dec.: −13.87±0.02 mas/yr
Parallax (π)10.2393±0.0170 mas
Distance318.5 ± 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 mas
Distance320 ± 1 ly
(98.0 ± 0.4 pc)
Orbit
PrimaryBD+34 4217Aa
SecondaryBD+34 4217Ab
Period (P)0.6311 d
Inclination (i)82.602±0.099°
Details
BD+34 4217Aa
Mass0.97 M☉
Radius0.893 R☉
Temperature5200 K
BD+34 4217Ab
Mass0.80 M☉
Radius0.838 R☉
Temperature4400 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
SIMBADdata

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. It was finally confirmed as the star CG Cygni B (BD+34 4217B) in 2020, at a 1.16 arcsecond separation from the primary.

Properties

The primary, BD+34 4217Aa, has a large number of starspots covering up to 18% of its surface. 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, 2003 and 2008.

References

  1. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  2. 1 2 "V* CG Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-11-02.
  3. 1 2 3 4 5 6 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, Bibcode:2005Ap.....48..291K, doi:10.1007/s10511-005-0028-1, S2CID 119716260
  4. 1 2 3 4 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  5. 1 2 3 4 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  6. 1 2 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, Bibcode:2012PASJ...64..121S, doi:10.1093/pasj/64.6.121
  7. 1 2 3 Afşar, M.; Heckert, P. A.; i̇Banoǧlu, C. (2004), "Long-term luminosity variations and period changes in CG Cygni", Astronomy & Astrophysics, 420 (2): 595–604, Bibcode:2004A&A...420..595A, doi:10.1051/0004-6361:20040115
  8. 1 2 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, arXiv:1709.06751, Bibcode:2017AJ....154...30K, doi:10.3847/1538-3881/aa7138, S2CID 118892024
  9. ↑ Laos, Stefan; Stassun, Keivan G.; Mathieu, Robert D. (2020), "Assessing Spectroscopic Binary Multiplicity Properties Using Robo-AO Imaging", The Astrophysical Journal, 902 (2): 107, arXiv:2009.00575, Bibcode:2020ApJ...902..107L, doi:10.3847/1538-4357/abb3fe, S2CID 221397474
  10. ↑ 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
  11. ↑ 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, Bibcode:2012ARep...56..281K, doi:10.1134/S1063772912030043, S2CID 122401754