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GJ 2069

{{Short description|Star system in the constellation Cancer}}

{{Starbox begin}}

{{Starbox observe 2s

| epoch = J2000

| constell = Cancer

| component1 = A

| ra1 = {{RA|08|31|37.57418}}

| dec1 = {{DEC|+19|23|39.3980}}

| appmag_v1 = 11.81

| component2 = B

| ra2 = {{RA|08|31|37.42279}}

| dec2 = {{DEC|+19|23|49.2821}}

| appmag_v2 = 14.83

}}

{{Starbox character

| component1 = A

| type = main sequence

| class = M3.5Ve + M3.5Ve

| variable = UV Cet+EB

| component2 = B

| type2 = main sequence

| class2 = M4.0Ve

| variable2 = UV Cet

}}

{{Starbox astrometry

| component1 = A

| radial_v =

| prop_mo_ra = −228.694

| prop_mo_dec = −119.919

| pm_footnote =

| parallax = 60.0602

| p_error = 0.0356

| parallax_footnote =

| absmag_v = 11.95 + 12.31

}}

{{Starbox astrometry|no_heading=y

| component1 = B

| radial_v = {{val|7.83|1.21}}

| prop_mo_ra = −232.878

| prop_mo_dec = −128.911

| pm_footnote =

| parallax = 60.2485

| p_error = 0.0764

| parallax_footnote =

| absmag_v =

| component2 = C

| radial_v2 =

| prop_mo_ra2 = −207.443

| prop_mo_dec2 = −125.513

| pm_footnote2 =

| parallax2 = 60.6896

| p_error2 = 0.1458

| parallax_footnote2 =

}}

{{Starbox orbit

| reference =

| primary = Aa

| name = Ab

| period_unitless = {{val|2.77146871|(34)|ul=d}}

| axis =

| axis_unitless =

| eccentricity =

| inclination = {{val|86.34|0.03}}

| node =

| periastron =

| periarg =

| periarg_primary =

| k1 =

| k2 =

}}

{{Starbox detail

| component1 = Aa

| mass = {{val|0.4358|0.0008}}

| radius = {{val|0.4122|0.0015}}

| luminosity = 0.0167

| gravity = {{val|4.804|0.011}}

| temperature = {{val|3160|150}}

| metal_fe =

| rotation =

| rotational_velocity =

| age_gyr =

| component2 = Ab

| mass2 = {{val|0.3998|0.0014}}

| radius2 = {{val|0.3817|0.0024}}

| luminosity2 = 0.0131

| gravity2 = {{val|4.854|0.021}}

| temperature2 = {{val|3125|150}}

| metal_fe2 =

| rotation2 =

| rotational_velocity2 =

| age_gyr2 =

}}

{{Starbox catalog

| names = {{odlist | CCDM=J08316+1924AB | GJ=2069}}

| component1 = A

| names1 = {{odlist | V=CU Cnc | HIP=41824 | L=1251-12 | LP=425-72 | LTT=12221 | NLTT=19685}}

| component2 = B

| names2 = {{odlist | V=CV Cnc | L=1251-13 | LP=425-7 | LTT=12222 | NLTT=19684}}

}}

{{Starbox reference

| Simbad = V*+CU+Cnc | sn=A

| Simbad2 = V*+CV+Cnc | sn2=BC

| Simbad3 = V*+CV+Cnc+A | sn3=B

| Simbad4 = V*+CV+Cnc+B | sn4=C

}}

{{Starbox end}}

GJ 2069 is a quintuple star system located {{convert|54|ly|pc|lk=on|abbr=off}} 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, but a 2024 study of the stellar magnetic fields found that the system is likely at least 1 billion years old.

System

{{chart/start}}

{{chart|border=1| | |, |S1| |S1=GJ 2069 Aa (CU Cnc A) }}

{{chart|border=0| |, |( |PA| |PA=Period = 2.8 d }}

{{chart|border=1| |! |` |S2| |S2=GJ 2069 Ab (CU Cnc B) }}

{{chart|border=0|, |( |PB| | |PB=0.68″ separation }}

{{chart|border=1|! |` |- |S3| |S3=GJ 2069 D }}

{{chart|border=0|( | |PC| | |PC=12″ separation }}

{{chart|border=1|! |, |- |S4| |S4=GJ 2069 B (CV Cnc A) }}

{{chart|border=0|` |( |PD| | |PD=0.36″ separation }}

{{chart|border=1| |` |- |S5| |S5=GJ 2069 C (CV Cnc B) }}

{{chart/end}}

Hierarchy of orbits in the GJ 2069 system

{{clear left}}

GJ 2069 A & B are separated by 12 arcseconds. Both are flare stars.

=GJ 2069 A (CU Cancri)=

File:CUCncLightCurve.png 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. 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). The stars appear fainter than other stars of the same mass, likely due to high starspot coverage.

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.

=GJ 2069 B (CV Cancri)=

File:CVCncLightCurve.png 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. It was resolved as a binary in 1999.

{{clear left}}

See also

References

{{reflist|refs=

{{cite simbad |title=V* CU Cnc |access-date=13 April 2025}}

{{cite simbad |title=V* CV Cnc |access-date=13 April 2025}}

{{Cite Gaia DR3|662732046688476288}}

{{Cite Gaia DR3|662732115407952768}}

{{Cite Gaia DR3|662732115405773824}}

{{cite web |title=MAST: Barbara A. Mikulski Archive for Space Telescopes |url=https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html |publisher=Space Telescope Science Institute |access-date=15 April 2025}}

{{cite journal |last1=Raetz |first1=St. |last2=Stelzer |first2=B. |last3=Damasso |first3=M. |last4=Scholz |first4=A. |title=Rotation-activity relations and flares of M dwarfs with K2 long- and short-cadence data |journal=Astronomy & Astrophysics |date=May 2020 |volume=637 |page=A22 |bibcode=2020A&A...637A..22R |doi=10.1051/0004-6361/201937350 |url=https://www.aanda.org/articles/aa/pdf/2020/05/aa37350-19.pdf |access-date=16 April 2025}}

{{cite web |url=http://djm.cc/constellation.html |title=Finding the constellation which contains given sky coordinates |date=2 August 2008 |website=djm.cc}}

{{cite web |title=CU Cnc |url=https://vizier.cds.unistra.fr/viz-bin/VizieR-S?V*%20CU%20Cnc |work=General Catalog of Variable Stars - VizieR |access-date=13 April 2025}}

{{cite web |title=CV Cnc |url=https://vizier.cds.unistra.fr/viz-bin/VizieR-S?V*%20CV%20Cnc |work=General Catalog of Variable Stars - VizieR |access-date=13 April 2025}}

{{cite journal |last1=Delfosse |first1=X. |last2=Forveille |first2=T. |display-authors=etal |date=January 1999 |title=GJ 2069A, a new M dwarf eclipsing binary |journal=Astronomy and Astrophysics |volume=341 |issue= |pages=L63–L66 |bibcode=1999A&A...341L..63D}}

{{cite journal |last1=Delfosse |first1=X. |last2=Forveille |first2=T. |display-authors=etal |date=April 1999 |title=New neighbours. I. 13 new companions to nearby M dwarfs |journal=Astronomy and Astrophysics |volume=344 |issue= |pages=897–910 |arxiv=astro-ph/9812008 |bibcode=1999A&A...344..897D}}

{{cite journal |last1=Ribas |first1=I. |date=January 2003 |title=The 0.4-Msun eclipsing binary CU Cancri. Absolute dimensions, comparison with evolutionary models and possible evidence for a circumstellar dust disk |journal=Astronomy and Astrophysics |volume=398 |issue= |pages=239–251 |doi=10.1051/0004-6361:20021609 |arxiv=astro-ph/0211086 |bibcode=2003A&A...398..239R}}

{{cite journal |last1=Beuzit |first1=J.-L. |last2=Ségransan |first2=D. |display-authors=etal |date=October 2004 |title=New neighbours. III. 21 new companions to nearby dwarfs, discovered with adaptive optics |journal=Astronomy and Astrophysics |volume=425 |issue= |pages=997–1008 |doi=10.1051/0004-6361:20048006 |arxiv=astro-ph/0106277 |bibcode=2004A&A...425..997B}}

{{cite journal |last1=Qian |first1=S.-B. |last2=Zhang |first2=J. |display-authors=etal |date=July 2012 |title=Optical flares and flaring oscillations on the M-type eclipsing binary CU Cancri |journal=Monthly Notices of the Royal Astronomical Society |volume=423 |issue=4 |pages=3646–3651 |doi=10.1111/j.1365-2966.2012.21157.x |doi-access=free |bibcode=2012MNRAS.423.3646Q}}

{{cite journal |last1=Wilson |first1=R. E. |last2=Pilachowski |first2=C. A. |last3=Terrell |first3=Dirk |date=February 2017 |title=The M Dwarf Eclipsing Binary CU Cancri |journal=The Astrophysical Journal |volume=835 |issue=2 |pages=251 |doi=10.3847/1538-4357/835/2/251 |doi-access=free |bibcode=2017ApJ...835..251W}}

{{cite journal |last1=Hahlin |first1=A. |last2=Kochukhov |first2=O. |display-authors=etal |date=April 2024 |title=Multi-scale magnetic field investigation of the M-dwarf eclipsing binary CU Cancri |journal=Astronomy & Astrophysics |volume=684 |issue= |pages=A175 |doi=10.1051/0004-6361/202348750 |arxiv=2402.00721 |bibcode=2024A&A...684A.175H}}

}}

{{Cancer (constellation)}}

Category:Cancer (constellation)

5

Category:M-type main-sequence stars

Category:Eclipsing binaries

2069

041824

Cancri, CU