Astronomy:GJ 2069
| Observation data {{#ifeq:J2000|J2000.0 (ICRS)|Epoch J2000.0 Equinox J2000.0 (ICRS)| [[History:Epoch|Epoch J2000]] [[Astronomy:Equinox (celestial coordinates)|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[2] mas/yr Dec.: −119.919[2] mas/yr |
| Parallax (π) | 60.0602 ± 0.0356[2] mas |
| 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[8] mas/yr Dec.: −128.911[8] mas/yr |
| Parallax (π) | 60.2485 ± 0.0764[8] mas |
| Distance | 54.14 ± 0.07 ly (16.60 ± 0.02 pc) |
| C | |
| Proper motion (μ) | RA: −207.443 mas/yr Dec.: −125.513 mas/yr |
| Parallax (π) | 60.6896 ± 0.1458[9] mas |
| Distance | 53.7 ± 0.1 ly (16.48 ± 0.04 pc) |
| Orbit[10] | |
| Primary | Aa |
| Companion | Ab |
| 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☉ |
| Luminosity | 0.0131[5] L☉ |
| Surface gravity (log g) | 4.854±0.021[5] cgs |
| Temperature | 3125±150[5] K |
| Other designations | |
| 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.
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)
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)
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
- ↑ "Finding the constellation which contains given sky coordinates". 2 August 2008. http://djm.cc/constellation.html.
- ↑ 2.0 2.1 2.2 2.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 "V* CU Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V%2A+CU+Cnc.
- ↑ 4.0 4.1 4.2 4.3 4.4 "V* CV Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V%2A+CV+Cnc.
- ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 5.10 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. doi:10.1051/0004-6361:20021609. Bibcode: 2003A&A...398..239R.
- ↑ 6.0 6.1 "CU Cnc". General Catalog of Variable Stars - VizieR. https://vizier.cds.unistra.fr/viz-bin/VizieR-S?V*%20CU%20Cnc.
- ↑ 7.0 7.1 "CV Cnc". General Catalog of Variable Stars - VizieR. https://vizier.cds.unistra.fr/viz-bin/VizieR-S?V*%20CV%20Cnc.
- ↑ 8.0 8.1 8.2 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 10.0 10.1 10.2 10.3 Hahlin, A. et al. (April 2024). "Multi-scale magnetic field investigation of the M-dwarf eclipsing binary CU Cancri". Astronomy & Astrophysics 684: A175. doi:10.1051/0004-6361/202348750. Bibcode: 2024A&A...684A.175H.
- ↑ 11.0 11.1 Wilson, R. E.; Pilachowski, C. A.; Terrell, Dirk (February 2017). "The M Dwarf Eclipsing Binary CU Cancri". The Astrophysical Journal 835 (2): 251. doi:10.3847/1538-4357/835/2/251. Bibcode: 2017ApJ...835..251W.
- ↑ 12.0 12.1 12.2 Beuzit, J.-L. et al. (October 2004). "New neighbours. III. 21 new companions to nearby dwarfs, discovered with adaptive optics". Astronomy and Astrophysics 425: 997–1008. doi:10.1051/0004-6361:20048006. Bibcode: 2004A&A...425..997B.
- ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html.
- ↑ Delfosse, X. et al. (January 1999). "GJ 2069A, a new M dwarf eclipsing binary". Astronomy and Astrophysics 341: L63–L66. Bibcode: 1999A&A...341L..63D.
- ↑ Qian, S.-B. 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. doi:10.1111/j.1365-2966.2012.21157.x. Bibcode: 2012MNRAS.423.3646Q.
- ↑ 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". Astronomy & Astrophysics 637: A22. doi:10.1051/0004-6361/201937350. Bibcode: 2020A&A...637A..22R. https://www.aanda.org/articles/aa/pdf/2020/05/aa37350-19.pdf. Retrieved 16 April 2025.
- ↑ Delfosse, X. et al. (April 1999). "New neighbours. I. 13 new companions to nearby M dwarfs". Astronomy and Astrophysics 344: 897–910. Bibcode: 1999A&A...344..897D.
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