GJ 2069

Last updated
GJ 2069
Observation data
Epoch J2000        Equinox J2000
Constellation Cancer [1]
A
Right ascension 08h 31m 37.57418s [2]
Declination +19° 23′ 39.3980″ [2]
Apparent magnitude  (V)11.81 [3]
B
Right ascension 08h 31m 37.42279s [4]
Declination +19° 23′ 49.2821″ [4]
Apparent magnitude  (V)14.83 [4]
Characteristics
A
Evolutionary stage main sequence
Spectral type M3.5Ve + M3.5Ve [5]
Variable type UV Cet+EB [6]
B
Evolutionary stage main sequence
Spectral type M4.0Ve [4]
Variable type UV Cet [7]
Astrometry
A
Proper motion (μ)RA: −228.694 mas/yr [2]
Dec.: −119.919 mas/yr [2]
Parallax (π)60.0602±0.0356  mas [2]
Distance 54.30 ± 0.03  ly
(16.650 ± 0.010  pc)
Absolute magnitude  (MV)11.95 + 12.31 [5]
B
Radial velocity (Rv)7.83±1.21 [8] km/s
Proper motion (μ)RA: −232.878 mas/yr [8]
Dec.: −128.911 mas/yr [8]
Parallax (π)60.2485±0.0764  mas [8]
Distance 54.14 ± 0.07  ly
(16.60 ± 0.02  pc)
C
Proper motion (μ)RA: −207.443  mas/yr [9]
Dec.: −125.513  mas/yr [9]
Parallax (π)60.6896 ± 0.1458  mas [9]
Distance 53.7 ± 0.1  ly
(16.48 ± 0.04  pc)
Orbit [10]
PrimaryAa
CompanionAb
Period (P)2.77146871(34)  d
Inclination (i)86.34±0.03°
Details
Aa
Mass 0.4358±0.0008 [10]   M☉
Radius 0.4122±0.0015 [11]   R☉
Luminosity 0.0167 [5]   L☉
Surface gravity (log g)4.804±0.011 [5]   cgs
Temperature 3160±150 [5]   K
Ab
Mass 0.3998±0.0014 [10]   M☉
Radius 0.3817±0.0024 [11]   R☉
Luminosity0.0131 [5]   L☉
Surface gravity (log g)4.854±0.021 [5]   cgs
Temperature 3125±150 [5]   K
Other designations
GJ 2069, CCDM J08316+1924AB
A: CU Cnc, HIP 41824, L 1251-12, LP 425-72, LTT 12221, NLTT 19685 [3]
B: CV Cnc, L 1251-13, LP 425-7, LTT 12222, NLTT 19684 [4]
Database references
SIMBAD A
BC
B
C

GJ 2069 is a quintuple star system located 54 light-years (17 parsecs ) away in the constellation Cancer. It appears near the Beehive Cluster in the sky, but it is closer than the cluster and is not a member of it. The system is composed of two sub-systems, GJ 2069 A & B, also known by their variable star designations CU Cancri and CV Cancri; both are binary, and GJ 2069 A has a third companion star, making five stars in total. All five stars are red dwarfs.

Contents

According to a 2003 study, the system is likely a member of the Castor Moving Group, with an age of 320 million years, [5] but a 2024 study of the stellar magnetic fields found that the system is likely at least 1 billion years old. [10]

System

GJ 2069 Aa (CU Cnc A)
Period = 2.8 d
GJ 2069 Ab (CU Cnc B)
0.68″ separation
GJ 2069 D
12″ separation
GJ 2069 B (CV Cnc A)
0.36″ separation
GJ 2069 C (CV Cnc B)

Hierarchy of orbits in the GJ 2069 system

GJ 2069 A & B are separated by 12 arcseconds. [12] Both are flare stars. [6] [7]

GJ 2069 A (CU Cancri)

A light curve for CU Cancri, plotted from TESS data CUCncLightCurve.png
A light curve for CU Cancri, plotted from TESS data

GJ 2069 A, also known as CU Cancri, is a close eclipsing binary orbiting every 2.8 days. Both stars are red dwarfs around 40% the mass of the Sun. [5] It was found to be a binary in 1999, and was the third known M-dwarf eclipsing binary, after CM Draconis and YY Geminorum (Castor C). [14] The stars appear fainter than other stars of the same mass, [5] likely due to high starspot coverage. [15]

GJ 2069 A also has a third companion star at a separation of 0.68 arcseconds, designated GJ 2069 D. It was found in 2001. [12]

GJ 2069 B (CV Cancri)

A light curve for CV Cancri showing Kepler data, adapted from Raetz et al. (2020) CVCncLightCurve.png
A light curve for CV Cancri showing Kepler data, adapted from Raetz et al. (2020)

GJ 2069 B, also known as CV Cancri, is a binary pair of red dwarfs, separated by 0.36 arcseconds. The companion star is also called GJ 2069 C. [12] It was resolved as a binary in 1999. [17]

See also

References

  1. ↑ "Finding the constellation which contains given sky coordinates". djm.cc. 2 August 2008.
  2. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 "V* CU Cnc". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 13 April 2025.
  4. 1 2 3 4 5 "V* CV Cnc". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 13 April 2025.
  5. 1 2 3 4 5 6 7 8 9 10 11 Ribas, I. (January 2003). "The 0.4-Msun eclipsing binary CU Cancri. Absolute dimensions, comparison with evolutionary models and possible evidence for a circumstellar dust disk". Astronomy and Astrophysics . 398: 239–251. arXiv: astro-ph/0211086 . Bibcode:2003A&A...398..239R. doi:10.1051/0004-6361:20021609.
  6. 1 2 "CU Cnc". General Catalog of Variable Stars - VizieR . Retrieved 13 April 2025.
  7. 1 2 "CV Cnc". General Catalog of Variable Stars - VizieR . Retrieved 13 April 2025.
  8. 1 2 3 4 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  9. 1 2 3 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  10. 1 2 3 4 Hahlin, A.; Kochukhov, O.; et al. (April 2024). "Multi-scale magnetic field investigation of the M-dwarf eclipsing binary CU Cancri". Astronomy & Astrophysics . 684: A175. arXiv: 2402.00721 . Bibcode:2024A&A...684A.175H. doi:10.1051/0004-6361/202348750.
  11. 1 2 Wilson, R. E.; Pilachowski, C. A.; Terrell, Dirk (February 2017). "The M Dwarf Eclipsing Binary CU Cancri". The Astrophysical Journal . 835 (2): 251. Bibcode:2017ApJ...835..251W. doi: 10.3847/1538-4357/835/2/251 .
  12. 1 2 3 Beuzit, J.-L.; Ségransan, D.; et al. (October 2004). "New neighbours. III. 21 new companions to nearby dwarfs, discovered with adaptive optics". Astronomy and Astrophysics . 425: 997–1008. arXiv: astro-ph/0106277 . Bibcode:2004A&A...425..997B. doi:10.1051/0004-6361:20048006.
  13. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 15 April 2025.
  14. ↑ Delfosse, X.; Forveille, T.; et al. (January 1999). "GJ 2069A, a new M dwarf eclipsing binary". Astronomy and Astrophysics . 341: L63 –L66. Bibcode:1999A&A...341L..63D.
  15. ↑ Qian, S.-B.; Zhang, J.; et al. (July 2012). "Optical flares and flaring oscillations on the M-type eclipsing binary CU Cancri". Monthly Notices of the Royal Astronomical Society . 423 (4): 3646–3651. Bibcode:2012MNRAS.423.3646Q. doi: 10.1111/j.1365-2966.2012.21157.x .
  16. ↑ Raetz, St.; Stelzer, B.; Damasso, M.; Scholz, A. (May 2020). "Rotation-activity relations and flares of M dwarfs with K2 long- and short-cadence data" (PDF). Astronomy & Astrophysics. 637: A22. Bibcode:2020A&A...637A..22R. doi:10.1051/0004-6361/201937350 . Retrieved 16 April 2025.
  17. ↑ Delfosse, X.; Forveille, T.; et al. (April 1999). "New neighbours. I. 13 new companions to nearby M dwarfs". Astronomy and Astrophysics . 344: 897–910. arXiv: astro-ph/9812008 . Bibcode:1999A&A...344..897D.
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